Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors suc...Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors such as genetic diversity and the impacts of climate and land-use changes,hindering effective conservation planning.To address these limitations,we developed an enhanced extinction risk assessment framework using Diploderma lizards as a model.This framework incorporates long-term field surveys,environmental data,and land-use information to predict distributional changes for 10 recently described Diploderma species on the Qinghai-Xizang Plateau,which hold ecological significance but remain underassessed in conservation assessment.By integrating the distribution data and genetically inferred effective population sizes(Ne),we conducted scenario analyses and used a rank-sum approach to calculate Risk ranking scores(RRS)for each species.This approach revealed significant discrepancies with the IUCN Red List assessments.Notably,D.yangi and D.qilin were identified as facing the highest extinction risk.Furthermore,D.vela,D.batangense,D.flaviceps,D.dymondi,D.yulongense,and D.laeviventre,currently classified as“Least Concern”,were found to warrant reclassification as“Vulnerable”due to considerable threat from projected range contractions.Exploring the relationship between morphology and RRS revealed that traits such as snout-vent length and relative tail length could serve as potential predictors of extinction risk,offering preliminary metrics for assessing species vulnerability when comprehensive data are unavailable.This study enhances the precision of extinction risk assessment frameworks and demonstrates their capacity to refine and update risk assessments,especially for lesser-known taxa.展开更多
In 2002, six cohorts ofbroodstock bay scallop Argopecten irradians irradians （Ne=1, 2, 10, 30, 50 and control） were randomly chosen from a population of bay scallop to produce offspring. After one year rearing, with...In 2002, six cohorts ofbroodstock bay scallop Argopecten irradians irradians （Ne=1, 2, 10, 30, 50 and control） were randomly chosen from a population of bay scallop to produce offspring. After one year rearing, with the progeny matured, the similar experiment was done to produce the F2 generation. To determine the magnitude of Ne effects, the growth and survival rates in larvae and adult of six F2 groups were compared. Results showed that inbreeding depression existed not only in the Ne=1 group but also in the Ne=2 group. The growth and survival rates of the two groups were significantly lower than those of the other groups （Ne=10, 30, 50, control）, and there were no significant differences among the latter （P〉0.05）. At the same time, the amount of depression in the Ne=1 group was significantly higher than that of the Ne=2 group （P〈0.05）. These results indicated that the low effective population size （Ne）, which increases the possibility of inbreeding, could lead to some harmful effects on the offspring. So it is essential to maintain a high level of Ne in commercial seed production. Fta＇thermore, as the high fecundity of bay scallop might lead to increased inbreeding, selecting broodstock from different growout sites is recommended.展开更多
A pocket coherent population trapping（CPT） atomic magnetometer scheme that uses a vertical cavity surface emitting laser as a light source is proposed and experimentally investigated.Using the differential detecting...A pocket coherent population trapping（CPT） atomic magnetometer scheme that uses a vertical cavity surface emitting laser as a light source is proposed and experimentally investigated.Using the differential detecting magneto–optic rotation effect,a CPT spectrum with the background canceled and a high signal-to-noise ratio is obtained.The experimental results reveal that the sensitivity of the proposed scheme can be improved by half an order,and the ability to detect weak magnetic fields is extended one-fold.Therefore,the proposed scheme is suited to realize a pocket-size CPT magnetometer.展开更多
Unbalanced parental contribution and small effective population size （Ne） are common issues during the artificial breeding of marine bivalves. The impact of hatchery-spawning practices on parental contribution, effe...Unbalanced parental contribution and small effective population size （Ne） are common issues during the artificial breeding of marine bivalves. The impact of hatchery-spawning practices on parental contribution, effective population size, the Ne/Nratio, and genetic diversity are largely unknown. To address this, we conducted a parentage analysis on a complete 3×3 diallel cross of clam Meretrix meretrix using eight microsatellite markers. The genetic diversity of the parents was higher than that of their respective offspring in most crosses （8/9）. Sires or dams from the same family contributed unequally to the pool of offspring from a particular cross, and the same parent clam exhibited large variation in parental contribution among different crosses. The variance in male contribution was higher than that of the female contribution in most crosses, suggesting that male contribution was more skewed than for females. The No/N ratio for nine crosses ranged from 0.58 to 0.86. There was no linear relationship between the sex ratio and the Ne/Nratio （P〉0.05）. Moreover, a sex ratio closer to one-to-one does not necessarily mean a larger effective population size. A solution to small effective population size in commercial breeding programs is increasing broodstoek numbers and attempting to maintain a balanced sex ratio.展开更多
Dear Editor, Nicotine is a psychoactive alkaloid that is thought to play a key role in addiction to commercial tobacco products [1] and cotinine is its primary metabolite [2]. Pharmacological treatment, such as nicoti...Dear Editor, Nicotine is a psychoactive alkaloid that is thought to play a key role in addiction to commercial tobacco products [1] and cotinine is its primary metabolite [2]. Pharmacological treatment, such as nicotine replacement therapy （NRT）, is a valid solution to this problem. Tobacco smoke contains many carcinogens such as nitrosamines .展开更多
A series of indicators, including serum lysozyme activity, G-banding chromosome aberration (G-banding CA) analysis, sister chromatid exchanges (SCEs), chromosome aberration (CA), T-lymphocyte transformation rate (TcTR...A series of indicators, including serum lysozyme activity, G-banding chromosome aberration (G-banding CA) analysis, sister chromatid exchanges (SCEs), chromosome aberration (CA), T-lymphocyte transformation rate (TcTR),-GT, GPT and AKP, were employed in the present survey among occupationally vinyl chloride (VC) exposed workers and inhabitants living in VC polluted area in a polyvinyl chloride (PVC) factory. The results showed that the serum lysozyme (S-LZM) activities in Group 3 (adult inhabitants exposed to 0.20 mg/m3 VC for at least 8 years), Group 2 (workers exposed to 4.1 mg/m3for at least 7 years occupationally), Group 1 (workers exposed to 25.7 mg/m3 for at least 2 years) were significantly higher than control. G-banding CA analysis showed that the total chromosome breakage rates in both Groups 1 and 2 were higher, but no difference existed between Group 3 and control. Only Group 1 was observed having higher SCEs, CA level and lower TcTR than control. AKP levels in Groups 1 and 2 were higher than control,but noγ-GT and GPT differences were found among groups. The study also suggests that G-banding CA analysis is more sensitive than CA and SCEs展开更多
The effects of monocrotophos and quinalphos on population and nitrogen-fixing activity of Azospirillum sp.in four agricultural soils were determined in a laboratory study.Concentrations of the two insecticides up to a...The effects of monocrotophos and quinalphos on population and nitrogen-fixing activity of Azospirillum sp.in four agricultural soils were determined in a laboratory study.Concentrations of the two insecticides up to a 5 kg ha^(-1)level were either stimulatory or innocuous to the popula- tion of Azospirillum in the soils.Four successive applications of the insecticides to soils resulted in a significant increase in the population density.Cultures of Azospirillum sp.,isolated from insecticide-treated soils,exhibited greater nitrogen-fixing activity.Three consecutive subcultur- ings of the isolates from insecticide-treated soils had no effect on their nitrogen-fixing activity.1989 Academic Press,Inc.展开更多
A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D...A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D-glucosaminidase （UNAG） was chosen as an effect biomarker. The UCd BMDLs for UNAG ranged from 2.18μg/g creatinine （cr） to 4.26μg/g cr in the populations of different provinces. The selection of the sample population and area affect the evaluation of the BMDL. The reference level of UCd for renal effects was further evaluated based on the data of all 6103 subjects. With benchmark responses （BMR） of 10%/5%, the overall UCd BMDLs for males in the total population were 3.73/2.08 μg/g cr. The BMD was slightly lower in females, thereby indicating that females may be relatively more sensitive to Cd exposure than are males.展开更多
The Ryman-Laikre （R-L） effect is an increase in inbreeding and a reduction in total effective population size （NET） in a combined captive-wild system, which arises when a few captive parents produce large numbers ...The Ryman-Laikre （R-L） effect is an increase in inbreeding and a reduction in total effective population size （NET） in a combined captive-wild system, which arises when a few captive parents produce large numbers of offspring. To facilitate evaluation of the R-L effect for scenarios that are relevant to marine stock enhancement and aquaculture, we extended the original R-L formula to explicitly account for several key factors that determine NeT, including the numbers of captive and wild adults, the ratio of captive to wild Ne/N （β）, productivity of captive and wild breeders, and removal of individuals from the wild for captive breeding. We show how to provide quantitative answers to questions such as： What scenarios lead to no loss of effective size？ What is the maximum effective size that can be achieved？ and What scenarios insure that NeTWill be no smaller than a specified value？ Important results include the following： （1） For large marine populations, the value of β becomes increasingly important as the captive contribution increases. Captive propagation will sharply reduce NeT unless the captive contribution is very small or β is very large （～10^3 or higher）. （2） Very large values of β are only possible if wild Ne/N is tiny. Therefore, large wild populations undergoing captive enhancement at even modest levels will suffer major reductions in effective size unless wild Ne is a tiny fraction of the census size （about 10 4 or lower）.展开更多
Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock ...Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock enhancement in the Bohai Bay in 2013. A total of 254 and 238 alleles were identified in the spawner and recaptured populations, respectively, and the numbers of alleles（N_a） were 8–63 and 6–60, respectively. The numbers of effective alleles（N_e） were 2.52–21.60 and 2.67–20.72, respectively. The polymorphism information content ranged from 0.529 to 0.952. The observed heterozygosity（H_o） values（0.638–0.910 and 0.712–0.927） were lower than the expected heterozygosity（H_e） values（0.603–0.954 and 0.625–0.952）, which indicated that the two populations possessed a rich genetic diversity. In 16 tests（2 populations×8 loci）, 13 tests deviated from the HardyWeinberg equilibrium. F_（is） values were positive at seven loci and the inbreeding coefficients（F） of the two populations estimated by trio ML were 13.234% and 11.603%, suggesting that there was a relatively high degree of inbreeding. A certain level of inbreeding depression had occurred in the Chinese shrimp population. F_（st） values ranged from 0 to 0.059, with a mean of 0.028, displaying a low level of genetic differentiation in the two populations. Effective population sizes（3 060.2 and 3 842.8） were higher than the minimum number suggested for retaining the evolutionary potential to adapt to new environmental conditions. For enhancement activity in 2014,the ideal number of captured shrimp spawners should have ranged from 7 686 to 19 214 to maintain genetic diversity and effective population size. Further strategies to adjust the balance of economic cost, fishing effort and ideal number of shrimp spawners to maintain a satisfactory effective population size for ensuring the sustainability of Chinese shrimp are proposed.展开更多
Severe population declines can reduce species to small populations, offering permissive conditions for deleterious processes. For example, following such events, species can become prone to inbreeding and genetic drif...Severe population declines can reduce species to small populations, offering permissive conditions for deleterious processes. For example, following such events, species can become prone to inbreeding and genetic drift which can lead to a loss of genetic diversity and evolutionary potentials. Hynobius chinensis is a poorly studied very rare and declining endangered amphibian species endemic to China in Changyang County. We investigated adult census population size by monitoring breeding populations from 2015 to 2018, developed microsatellite markers from the transcriptome and used them to investigate genetic diversity, and a population bottleneck in this species. We found H. chinensis in 4 different localities in a total area of 2.18 km^2 and estimated the overall adult census population size at 386–404 individuals. The adult census size（mean ± SE） per breeding pond ranged from 44 ± 6 to 141 ± 8 individuals and appeared smaller than that reported in closely related species in undisturbed habitats. We developed and characterized 13 microsatellite markers in total. Analysis of data at 7 loci（N = 118） in Hardy-Weinberg equilibrium gathered from the largest population showed that genetic diversity level was low. The average number of alleles per locus was 2.14. The observed and expected heterozygosities averaged 0.38 and 0.40, respectively. The inbreeding coefficient was –0.06. All tests performed to investigate a population bottleneck, i.e. The Garza-Williamson test, Heterozygosity excess test, Mode shift test of allele frequency, and effective population size estimates detected a population bottleneck. The contemporary and the historical effective population sizes were estimated at 36 and 234 individuals, respectively. We argue that as bottleneck effects, the studied population may have become prone to genetic drift and inbreeding, losing microsatellite alleles and heterozygosity. Our results suggest that populations of H. chinensismay have been extirpated in the study area.展开更多
We made an on-site investigation about pedestrian violation of traffic signals at a signalized intersection in Xi＇an, Shaanxi province, China. Based on it, we studied the impact of pedestrian＇s waiting time on viola...We made an on-site investigation about pedestrian violation of traffic signals at a signalized intersection in Xi＇an, Shaanxi province, China. Based on it, we studied the impact of pedestrian＇s waiting time on violation decision and the impact of the number of pedestrians in colony on the probability of swarming pedestrians＇ violation. The result revealed that the probability of pedestrian violation rose with the waiting time for the pedestrians＇ green signal. Then we developed a Monte Carlo model for simulating mixed vehicles and pedestrians and used the on-site investigation data to validate the model. When traffic volume is fight, the error between the simulated values and the measured ones is 2.67%. When traffic volume is heavy, the error is 3.38%.展开更多
To explore the genetic features and signatures of selection in indigenous pigs from South China and Duroc pigs,259 pigs from six populations were genotyped using single-nucleotide polymorphism(SNP)BeadChips.Principal ...To explore the genetic features and signatures of selection in indigenous pigs from South China and Duroc pigs,259 pigs from six populations were genotyped using single-nucleotide polymorphism(SNP)BeadChips.Principal component analysis(PCA),effective population size(Ne),linkage disequilibrium(LD),and signatures of selection were explored and investigated among the six pig populations.The results showed the Ne of five South China indigenous pig populations has been decreasing rapidly since 100 generations ago.The LD between pairwise SNP distance at 100 kb ranged from 0.16 to 0.20 for the five indigenous pig populations,while it was 0.32 for the Duroc population.However,the LD of all six pig populations showed the opposite order at long distances(>5 Mb).Furthermore,15 potential signatures of selection associated with meat quality and age at puberty were exclusively detected in South China indigenous pigs,while eight potential signatures of selection associated with growth traits were detected in Duroc pigs.Our work provides valuable insights for the utilization and conservation of South China indigenous pigs.展开更多
Abstract Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding pro- grams in China were examined at ten polymorphic microsatellite loci to assess the lev...Abstract Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding pro- grams in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8-20.6, and a mean expected heterozygosity of 0.902-0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a rela- tively large number ofbroodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided im- portant information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.展开更多
Behavioral research has long had an important role in the conservation of terns （Ayes： Stemidae）. Habitat management and restoration of breeding colony sites depends on knowledge of the cues used to select colony a...Behavioral research has long had an important role in the conservation of terns （Ayes： Stemidae）. Habitat management and restoration of breeding colony sites depends on knowledge of the cues used to select colony and nest sites. For example, conspecific attraction with playback and decoys is commonly used to bring terns to suitable colony sites and habitat modification is often used to increase the availability of suitable nest sites. Tern colonies are interconnected by dispersal, and a metapopulation approach is needed for effective management. Population dynamics are therefore affected by behaviors that influence the frequency of movement among colony sites： site fidelity, natal and breeding dispersal, and group adherence. The monogamous breeding system of terns should keep effective population size similar to census population size, but variation in sex ratios （likely resulting from sex differences in behavior） and in parental quality can result in a smaller than expected effective population size. In addition to the behavior of terns, knowledge of the behavior of predators on terns contributes to management plans, because predator behavior can sometimes be manipulated and predation is often performed by only a few specialized individuals. Other examples of links between tern behavior and conservation are also briefly reviewed, such as behavioral toxicology research and studies of behavioral responses to human disturbance and manmade structures. More work is needed on the behavior of migratory terns at staging sites, stopover sites and wintering grounds, and on the behavior of less well-studied species and species in less well-studied geographic regions [Current Zoology 60 （4）： 500-514, 2014].展开更多
In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographi...In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographic dynamics.The Iberian painted frog(Discoglossus galganoi)is endemic to Spain and Portugal and shows decreasing population trends across its range,but few studies have attempted to estimate census sizes or assess genetic diversity in wild populations,and little is known about their reproductive biology.We applied an integrative approach based on the combination of capture-mark-recapture data and multilocus genotypes to monitor a breeding population of D.galganoi in central Spain during two consecutive breeding seasons,focusing on the estimation of demographic parameters and their temporal variation.Specifically,we estimated the number of adults(Na),the effective population size(Ne),and the effective number of breeders(Nb),as well as survival and migration rates.We documented a>50%decrease in the estimated number of adults of both sexes between the breeding seasons of 2018 and 2019,probably associated with reduced rainfall in the latter.Estimates of Nb and the Nb/Na ratio were low in both seasons,with a 20–30%decrease in Nb and a 47%increase in the Nb/Na ratio in 2019.Based on the reconstruction of pedigrees from larval and adult genotypes,we provide the first genetic evidence of polygamy in males and females of D.galganoi and the first estimates of breeding success in the species.展开更多
Investment in silvicultural techniques is noticeably lacking,especially in breeding programs for non-conventional wood species.Studying genotype×environment interaction(G×E)is essential to the development of...Investment in silvicultural techniques is noticeably lacking,especially in breeding programs for non-conventional wood species.Studying genotype×environment interaction(G×E)is essential to the development of breeding programs.Thus,this study aimed to estimate genetic diversity of and the effects of G×E interaction on two progeny tests of Cordia trichotoma,including the estimation of genetic gain and genetic diversity after selection.For the experiment,30 progenies of C.trichotoma were tested at two sites with differing soil textures.Diameter at breast height(1.30 m above soil surface,dbh-cm),total height,diameter at 30 cm from the soil,first branch height,and survival were all monitored for four years.Statistical deviance,best linear unbiased estimator,and harmonic mean of relative performance of genetic values(MHPRVG)were all calculated to predict breeding values,estimate genetic parameters,and analyze deviance.All quantified traits varied significantly among progenies by soil type,with greatest variation recorded for genetic variability.Heritability of the progenies led to predictions of genetic gain,ranging from 7.73 to 15.45%,for dbh at four years of age.The calculated decrease in genetic diversity after selection showed that this parameter should be monitored in subsequent breeding cycles.G×E was low for all tests.The best-performing progenies proved most stable and best adapted to the different environmental conditions tested.展开更多
Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation.To date,however,little is known about the levels and distribution of genetic diversity of Drymis brasilie...Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation.To date,however,little is known about the levels and distribution of genetic diversity of Drymis brasiliensis(Miers LC),a tree species from the Atlantic Rainforest.Therefore,in this study,we investigated how genetic diversity is distributed within and among populations of D.brasiliensis from southern Brazil using allozyme markers to genotype reproductive trees(8 populations)and seedlings(3 populations).Furthermore,in two populations,we established two permanent plots(5.1 and 1 ha)to analyze fine-scale genetic structure(FSGS).Studied populations presented low levels of genetic diversity(reproductive=0.085;seedlings=0.054)and high fixation indexes(reproductive=0.396;seedlings=0.231).Genetic divergence among populations was equal to 0.05,which is significant,signaling that few populations can conserve large portions of the species total genetic diversity.FSGS was only detected for one population,when reproductive individuals were separated by less than40 m.Low genetic diversity combined with high fixation indexes clearly signal a risk of losing diversity.Therefore,conservation efforts should be aimed at enhancing gene flow within the studied populations.展开更多
Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of sp...Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of species experiencing popula-tion decline within subgenus Thoracobombus is higher than average.Bombus opulentus is 1 species in Thoracobombus,but little is known about its recent population dynamics.Here,we employed conservation genomics methods to investigate the population dynam-ics of B.opulentus during the recent past and identify the likely environmental factors that may cause population decline.Firstly,we placed the scaffold-level of B.opulentus ref-erence genome sequence onto chromosome-level using Hi-C technique.Then,based on this reference genome and whole-genome resequencing data for 51 B.opulentus samples,we reconstructed the population structure and effective population size(Ne)trajectories of B.opulentus and identified genes that were under positive selection.Our results revealed that the collected B.opulentus samples could be divided into 2 populations,and 1 of them experienced a recent population decline;the declining population also exhibited lower ge-netic diversity and higher inbreeding levels.Genes related to high-temperature tolerance,immune response,and detoxication showed signals of positive selection in the declining population,suggesting that climate warming and pathogen/pesticide exposures may con-tribute to the decline of this B.opulentus population.Taken together,our study provided insights into the demography of B.opulentus populations and highlighted that popula-tions of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.展开更多
Local cattle breeds continue to decline in numbers partly due to the use of high performing breeds in advanced production systems where genetic material of elite animals is widely spread. The objective of this study w...Local cattle breeds continue to decline in numbers partly due to the use of high performing breeds in advanced production systems where genetic material of elite animals is widely spread. The objective of this study was to assess the within and across breed genetic diversity of the Angler and Red-and-White dual-purpose (DP) cattle breeds applying different inbreeding concepts. Classical and ancestral inbreeding coefficients were computed from pedigree data using the gene dropping method. Effective population size was calculated based on the increase of classical inbreeding, and based on ancestral inbreeding to obtain what was termed as ancestral effective population size. Furthermore, the effective number of founders and ancestors were computed to assess the disequilibrium of founder contribution in the reference populations. The analyses were performed separately for each breed and for a combined dataset. The Angler pedigree was more complete (88%) in the first parental generation but completeness declined with increasing pedigree depth. Average classical inbreeding coefficients of inbred individuals were 2.19%, 1.94% and 2.07%, while average Ballou’s ancestral inbreeding coefficients were 3.69%, 1.39% and 2.21% for the Angler, Red-and-White DP and the combined breed pedigree analyses, respectively. Ancestral history coefficient is a novel coefficient and its estimates were similar and strongly correlated to Ballou’s coefficients (r = 0.99, p < 0.001). The effective population size estimates ranged from 156 to 170 for the classical inbreeding based method, and as low as from 50 to 54 for the ancestral history coefficient based method. The effective number of founders and ancestors ranged from 310 to 532, and 90 to 189, respectively. Our results show that the Red Holstein breed is a key progenitor of the breed populations under study. This highlights cross breeding schemes introduced to improve the milk trait performance of the Angler and Red-and-White DP breeds some decades ago.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP,2019QZKK0402)Science and Technology Plan Project of Xizang Autonomous Region to Y.Q. (XZ202201ZY0030G)National Natural Science Foundation of China (32201424 to Z.Y.L.and 31872233 to Y.Q.)。
文摘Assessing the threat status of species in response to global change is critical for biodiversity monitoring and conservation efforts.However,current frameworks,even the IUCN Red List,often neglect critical factors such as genetic diversity and the impacts of climate and land-use changes,hindering effective conservation planning.To address these limitations,we developed an enhanced extinction risk assessment framework using Diploderma lizards as a model.This framework incorporates long-term field surveys,environmental data,and land-use information to predict distributional changes for 10 recently described Diploderma species on the Qinghai-Xizang Plateau,which hold ecological significance but remain underassessed in conservation assessment.By integrating the distribution data and genetically inferred effective population sizes(Ne),we conducted scenario analyses and used a rank-sum approach to calculate Risk ranking scores(RRS)for each species.This approach revealed significant discrepancies with the IUCN Red List assessments.Notably,D.yangi and D.qilin were identified as facing the highest extinction risk.Furthermore,D.vela,D.batangense,D.flaviceps,D.dymondi,D.yulongense,and D.laeviventre,currently classified as“Least Concern”,were found to warrant reclassification as“Vulnerable”due to considerable threat from projected range contractions.Exploring the relationship between morphology and RRS revealed that traits such as snout-vent length and relative tail length could serve as potential predictors of extinction risk,offering preliminary metrics for assessing species vulnerability when comprehensive data are unavailable.This study enhances the precision of extinction risk assessment frameworks and demonstrates their capacity to refine and update risk assessments,especially for lesser-known taxa.
基金This study was supported by the Project of Scientific Innovation of the Chinese Academy of Sciences under contract No.ZKCX2-211the Science and Technology Plans of Shandong Province under contract No.022110107the Science and Technology Plans of Qingdao under contract No.03-1-HH-10.
文摘In 2002, six cohorts ofbroodstock bay scallop Argopecten irradians irradians （Ne=1, 2, 10, 30, 50 and control） were randomly chosen from a population of bay scallop to produce offspring. After one year rearing, with the progeny matured, the similar experiment was done to produce the F2 generation. To determine the magnitude of Ne effects, the growth and survival rates in larvae and adult of six F2 groups were compared. Results showed that inbreeding depression existed not only in the Ne=1 group but also in the Ne=2 group. The growth and survival rates of the two groups were significantly lower than those of the other groups （Ne=10, 30, 50, control）, and there were no significant differences among the latter （P〉0.05）. At the same time, the amount of depression in the Ne=1 group was significantly higher than that of the Ne=2 group （P〈0.05）. These results indicated that the low effective population size （Ne）, which increases the possibility of inbreeding, could lead to some harmful effects on the offspring. So it is essential to maintain a high level of Ne in commercial seed production. Fta＇thermore, as the high fecundity of bay scallop might lead to increased inbreeding, selecting broodstock from different growout sites is recommended.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304362 and 61434005)
文摘A pocket coherent population trapping（CPT） atomic magnetometer scheme that uses a vertical cavity surface emitting laser as a light source is proposed and experimentally investigated.Using the differential detecting magneto–optic rotation effect,a CPT spectrum with the background canceled and a high signal-to-noise ratio is obtained.The experimental results reveal that the sensitivity of the proposed scheme can be improved by half an order,and the ability to detect weak magnetic fields is extended one-fold.Therefore,the proposed scheme is suited to realize a pocket-size CPT magnetometer.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A410)the Key Technology R&D Program of Jiangsu Province,China(No.BE2011372)
文摘Unbalanced parental contribution and small effective population size （Ne） are common issues during the artificial breeding of marine bivalves. The impact of hatchery-spawning practices on parental contribution, effective population size, the Ne/Nratio, and genetic diversity are largely unknown. To address this, we conducted a parentage analysis on a complete 3×3 diallel cross of clam Meretrix meretrix using eight microsatellite markers. The genetic diversity of the parents was higher than that of their respective offspring in most crosses （8/9）. Sires or dams from the same family contributed unequally to the pool of offspring from a particular cross, and the same parent clam exhibited large variation in parental contribution among different crosses. The variance in male contribution was higher than that of the female contribution in most crosses, suggesting that male contribution was more skewed than for females. The No/N ratio for nine crosses ranged from 0.58 to 0.86. There was no linear relationship between the sex ratio and the Ne/Nratio （P〉0.05）. Moreover, a sex ratio closer to one-to-one does not necessarily mean a larger effective population size. A solution to small effective population size in commercial breeding programs is increasing broodstoek numbers and attempting to maintain a balanced sex ratio.
基金partly supported by the National Natural Science Foundation of China(81271475 and 81571297)
文摘Dear Editor, Nicotine is a psychoactive alkaloid that is thought to play a key role in addiction to commercial tobacco products [1] and cotinine is its primary metabolite [2]. Pharmacological treatment, such as nicotine replacement therapy （NRT）, is a valid solution to this problem. Tobacco smoke contains many carcinogens such as nitrosamines .
文摘A series of indicators, including serum lysozyme activity, G-banding chromosome aberration (G-banding CA) analysis, sister chromatid exchanges (SCEs), chromosome aberration (CA), T-lymphocyte transformation rate (TcTR),-GT, GPT and AKP, were employed in the present survey among occupationally vinyl chloride (VC) exposed workers and inhabitants living in VC polluted area in a polyvinyl chloride (PVC) factory. The results showed that the serum lysozyme (S-LZM) activities in Group 3 (adult inhabitants exposed to 0.20 mg/m3 VC for at least 8 years), Group 2 (workers exposed to 4.1 mg/m3for at least 7 years occupationally), Group 1 (workers exposed to 25.7 mg/m3 for at least 2 years) were significantly higher than control. G-banding CA analysis showed that the total chromosome breakage rates in both Groups 1 and 2 were higher, but no difference existed between Group 3 and control. Only Group 1 was observed having higher SCEs, CA level and lower TcTR than control. AKP levels in Groups 1 and 2 were higher than control,but noγ-GT and GPT differences were found among groups. The study also suggests that G-banding CA analysis is more sensitive than CA and SCEs
文摘The effects of monocrotophos and quinalphos on population and nitrogen-fixing activity of Azospirillum sp.in four agricultural soils were determined in a laboratory study.Concentrations of the two insecticides up to a 5 kg ha^(-1)level were either stimulatory or innocuous to the popula- tion of Azospirillum in the soils.Four successive applications of the insecticides to soils resulted in a significant increase in the population density.Cultures of Azospirillum sp.,isolated from insecticide-treated soils,exhibited greater nitrogen-fixing activity.Three consecutive subcultur- ings of the isolates from insecticide-treated soils had no effect on their nitrogen-fixing activity.1989 Academic Press,Inc.
基金financially supported by Special Funds of the State Environmental Protection Public Welfare Industry(201009049201309049)+1 种基金National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2013BAI12B03)the Fundamental Research Funds for the Central Universities(2015JBM108)
文摘A survey involving 6103 participants from five Chinese provinces was conducted to evaluate the threshold value of urinary cadmium （UCd） for renal dysfunction as benchmark dose low （BMDL）. The urinary N-acetyl-13-D-glucosaminidase （UNAG） was chosen as an effect biomarker. The UCd BMDLs for UNAG ranged from 2.18μg/g creatinine （cr） to 4.26μg/g cr in the populations of different provinces. The selection of the sample population and area affect the evaluation of the BMDL. The reference level of UCd for renal effects was further evaluated based on the data of all 6103 subjects. With benchmark responses （BMR） of 10%/5%, the overall UCd BMDLs for males in the total population were 3.73/2.08 μg/g cr. The BMD was slightly lower in females, thereby indicating that females may be relatively more sensitive to Cd exposure than are males.
文摘The Ryman-Laikre （R-L） effect is an increase in inbreeding and a reduction in total effective population size （NET） in a combined captive-wild system, which arises when a few captive parents produce large numbers of offspring. To facilitate evaluation of the R-L effect for scenarios that are relevant to marine stock enhancement and aquaculture, we extended the original R-L formula to explicitly account for several key factors that determine NeT, including the numbers of captive and wild adults, the ratio of captive to wild Ne/N （β）, productivity of captive and wild breeders, and removal of individuals from the wild for captive breeding. We show how to provide quantitative answers to questions such as： What scenarios lead to no loss of effective size？ What is the maximum effective size that can be achieved？ and What scenarios insure that NeTWill be no smaller than a specified value？ Important results include the following： （1） For large marine populations, the value of β becomes increasingly important as the captive contribution increases. Captive propagation will sharply reduce NeT unless the captive contribution is very small or β is very large （～10^3 or higher）. （2） Very large values of β are only possible if wild Ne/N is tiny. Therefore, large wild populations undergoing captive enhancement at even modest levels will suffer major reductions in effective size unless wild Ne is a tiny fraction of the census size （about 10 4 or lower）.
基金The National Basic Research Program of China(973 Program)Adaptive Response of Fishery Species to Environmental Changes and Their Effects on Population Dynamics under contract No.2015CB453303the International Science&Technology Cooperation Program of China under contract No.2013DFA31410
文摘Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp（Fenneropenaeus chinensis） during stock enhancement in the Bohai Bay in 2013. A total of 254 and 238 alleles were identified in the spawner and recaptured populations, respectively, and the numbers of alleles（N_a） were 8–63 and 6–60, respectively. The numbers of effective alleles（N_e） were 2.52–21.60 and 2.67–20.72, respectively. The polymorphism information content ranged from 0.529 to 0.952. The observed heterozygosity（H_o） values（0.638–0.910 and 0.712–0.927） were lower than the expected heterozygosity（H_e） values（0.603–0.954 and 0.625–0.952）, which indicated that the two populations possessed a rich genetic diversity. In 16 tests（2 populations×8 loci）, 13 tests deviated from the HardyWeinberg equilibrium. F_（is） values were positive at seven loci and the inbreeding coefficients（F） of the two populations estimated by trio ML were 13.234% and 11.603%, suggesting that there was a relatively high degree of inbreeding. A certain level of inbreeding depression had occurred in the Chinese shrimp population. F_（st） values ranged from 0 to 0.059, with a mean of 0.028, displaying a low level of genetic differentiation in the two populations. Effective population sizes（3 060.2 and 3 842.8） were higher than the minimum number suggested for retaining the evolutionary potential to adapt to new environmental conditions. For enhancement activity in 2014,the ideal number of captured shrimp spawners should have ranged from 7 686 to 19 214 to maintain genetic diversity and effective population size. Further strategies to adjust the balance of economic cost, fishing effort and ideal number of shrimp spawners to maintain a satisfactory effective population size for ensuring the sustainability of Chinese shrimp are proposed.
基金financially supported by the Chinese National Science and Technology Basic Work Program (No. 2014FY110100)the State Forestry Administration of China
文摘Severe population declines can reduce species to small populations, offering permissive conditions for deleterious processes. For example, following such events, species can become prone to inbreeding and genetic drift which can lead to a loss of genetic diversity and evolutionary potentials. Hynobius chinensis is a poorly studied very rare and declining endangered amphibian species endemic to China in Changyang County. We investigated adult census population size by monitoring breeding populations from 2015 to 2018, developed microsatellite markers from the transcriptome and used them to investigate genetic diversity, and a population bottleneck in this species. We found H. chinensis in 4 different localities in a total area of 2.18 km^2 and estimated the overall adult census population size at 386–404 individuals. The adult census size（mean ± SE） per breeding pond ranged from 44 ± 6 to 141 ± 8 individuals and appeared smaller than that reported in closely related species in undisturbed habitats. We developed and characterized 13 microsatellite markers in total. Analysis of data at 7 loci（N = 118） in Hardy-Weinberg equilibrium gathered from the largest population showed that genetic diversity level was low. The average number of alleles per locus was 2.14. The observed and expected heterozygosities averaged 0.38 and 0.40, respectively. The inbreeding coefficient was –0.06. All tests performed to investigate a population bottleneck, i.e. The Garza-Williamson test, Heterozygosity excess test, Mode shift test of allele frequency, and effective population size estimates detected a population bottleneck. The contemporary and the historical effective population sizes were estimated at 36 and 234 individuals, respectively. We argue that as bottleneck effects, the studied population may have become prone to genetic drift and inbreeding, losing microsatellite alleles and heterozygosity. Our results suggest that populations of H. chinensismay have been extirpated in the study area.
基金The National Natural Science Foundation of China (No.60134010)
文摘We made an on-site investigation about pedestrian violation of traffic signals at a signalized intersection in Xi＇an, Shaanxi province, China. Based on it, we studied the impact of pedestrian＇s waiting time on violation decision and the impact of the number of pedestrians in colony on the probability of swarming pedestrians＇ violation. The result revealed that the probability of pedestrian violation rose with the waiting time for the pedestrians＇ green signal. Then we developed a Monte Carlo model for simulating mixed vehicles and pedestrians and used the on-site investigation data to validate the model. When traffic volume is fight, the error between the simulated values and the measured ones is 2.67%. When traffic volume is heavy, the error is 3.38%.
基金the National Key R&D Program of China(2018YFD0501200)the earmarked fund for China Agriculture Research System(CARS-35)the Key R&D Program of Guangdong Province,China(2018B020203003)。
文摘To explore the genetic features and signatures of selection in indigenous pigs from South China and Duroc pigs,259 pigs from six populations were genotyped using single-nucleotide polymorphism(SNP)BeadChips.Principal component analysis(PCA),effective population size(Ne),linkage disequilibrium(LD),and signatures of selection were explored and investigated among the six pig populations.The results showed the Ne of five South China indigenous pig populations has been decreasing rapidly since 100 generations ago.The LD between pairwise SNP distance at 100 kb ranged from 0.16 to 0.20 for the five indigenous pig populations,while it was 0.32 for the Duroc population.However,the LD of all six pig populations showed the opposite order at long distances(>5 Mb).Furthermore,15 potential signatures of selection associated with meat quality and age at puberty were exclusively detected in South China indigenous pigs,while eight potential signatures of selection associated with growth traits were detected in Duroc pigs.Our work provides valuable insights for the utilization and conservation of South China indigenous pigs.
基金supported by grants from the National High Technology Research and Development Program (2012AA10A405-6)National Natural Science Foundation of China (31372524)Special Fund for Independent Innovation of Shandong Province (2013CX80202)
文摘Abstract Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding pro- grams in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8-20.6, and a mean expected heterozygosity of 0.902-0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a rela- tively large number ofbroodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided im- portant information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.
文摘Behavioral research has long had an important role in the conservation of terns （Ayes： Stemidae）. Habitat management and restoration of breeding colony sites depends on knowledge of the cues used to select colony and nest sites. For example, conspecific attraction with playback and decoys is commonly used to bring terns to suitable colony sites and habitat modification is often used to increase the availability of suitable nest sites. Tern colonies are interconnected by dispersal, and a metapopulation approach is needed for effective management. Population dynamics are therefore affected by behaviors that influence the frequency of movement among colony sites： site fidelity, natal and breeding dispersal, and group adherence. The monogamous breeding system of terns should keep effective population size similar to census population size, but variation in sex ratios （likely resulting from sex differences in behavior） and in parental quality can result in a smaller than expected effective population size. In addition to the behavior of terns, knowledge of the behavior of predators on terns contributes to management plans, because predator behavior can sometimes be manipulated and predation is often performed by only a few specialized individuals. Other examples of links between tern behavior and conservation are also briefly reviewed, such as behavioral toxicology research and studies of behavioral responses to human disturbance and manmade structures. More work is needed on the behavior of migratory terns at staging sites, stopover sites and wintering grounds, and on the behavior of less well-studied species and species in less well-studied geographic regions [Current Zoology 60 （4）： 500-514, 2014].
基金the Ethics Committee of Consejo Superior de Investigaciones Científicas,Spain(ref.:710/2018)and Comunidad de Madrid(ref.:PROEX 040/19)which also extended legal permits for tissue collection for scientific purposes(ref.:10/069513.9/18).
文摘In the face of worldwide amphibian declines,integrative studies combining individual-based information and genetic data represent a powerful approach to produce robust,reliable,and comparable assessments of demographic dynamics.The Iberian painted frog(Discoglossus galganoi)is endemic to Spain and Portugal and shows decreasing population trends across its range,but few studies have attempted to estimate census sizes or assess genetic diversity in wild populations,and little is known about their reproductive biology.We applied an integrative approach based on the combination of capture-mark-recapture data and multilocus genotypes to monitor a breeding population of D.galganoi in central Spain during two consecutive breeding seasons,focusing on the estimation of demographic parameters and their temporal variation.Specifically,we estimated the number of adults(Na),the effective population size(Ne),and the effective number of breeders(Nb),as well as survival and migration rates.We documented a>50%decrease in the estimated number of adults of both sexes between the breeding seasons of 2018 and 2019,probably associated with reduced rainfall in the latter.Estimates of Nb and the Nb/Na ratio were low in both seasons,with a 20–30%decrease in Nb and a 47%increase in the Nb/Na ratio in 2019.Based on the reconstruction of pedigrees from larval and adult genotypes,we provide the first genetic evidence of polygamy in males and females of D.galganoi and the first estimates of breeding success in the species.
基金funded by Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)。
文摘Investment in silvicultural techniques is noticeably lacking,especially in breeding programs for non-conventional wood species.Studying genotype×environment interaction(G×E)is essential to the development of breeding programs.Thus,this study aimed to estimate genetic diversity of and the effects of G×E interaction on two progeny tests of Cordia trichotoma,including the estimation of genetic gain and genetic diversity after selection.For the experiment,30 progenies of C.trichotoma were tested at two sites with differing soil textures.Diameter at breast height(1.30 m above soil surface,dbh-cm),total height,diameter at 30 cm from the soil,first branch height,and survival were all monitored for four years.Statistical deviance,best linear unbiased estimator,and harmonic mean of relative performance of genetic values(MHPRVG)were all calculated to predict breeding values,estimate genetic parameters,and analyze deviance.All quantified traits varied significantly among progenies by soil type,with greatest variation recorded for genetic variability.Heritability of the progenies led to predictions of genetic gain,ranging from 7.73 to 15.45%,for dbh at four years of age.The calculated decrease in genetic diversity after selection showed that this parameter should be monitored in subsequent breeding cycles.G×E was low for all tests.The best-performing progenies proved most stable and best adapted to the different environmental conditions tested.
基金The work was supported by the Fundo Rotativo de Estímulo à Pesquisa Agropecuária do Estado de Santa Catarina(FEPA),Aperfeicoamento de Pessoal de Nível Superior(CAPES)to TM,Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq:,the Coordenacāo de,and the)to MSR(304724/2010-6).
文摘Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation.To date,however,little is known about the levels and distribution of genetic diversity of Drymis brasiliensis(Miers LC),a tree species from the Atlantic Rainforest.Therefore,in this study,we investigated how genetic diversity is distributed within and among populations of D.brasiliensis from southern Brazil using allozyme markers to genotype reproductive trees(8 populations)and seedlings(3 populations).Furthermore,in two populations,we established two permanent plots(5.1 and 1 ha)to analyze fine-scale genetic structure(FSGS).Studied populations presented low levels of genetic diversity(reproductive=0.085;seedlings=0.054)and high fixation indexes(reproductive=0.396;seedlings=0.231).Genetic divergence among populations was equal to 0.05,which is significant,signaling that few populations can conserve large portions of the species total genetic diversity.FSGS was only detected for one population,when reproductive individuals were separated by less than40 m.Low genetic diversity combined with high fixation indexes clearly signal a risk of losing diversity.Therefore,conservation efforts should be aimed at enhancing gene flow within the studied populations.
基金This work was supported by the National Natural Science Foundation of China(Grant numbers 32270445 and 31971397)the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 14th Fiveyear Plan(Grant number BPHR20220114)the Central Public-interest Scientific Institution Basal Research Fund(Grant numbers Y2019XK13 and Y2021XK16).
文摘Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of species experiencing popula-tion decline within subgenus Thoracobombus is higher than average.Bombus opulentus is 1 species in Thoracobombus,but little is known about its recent population dynamics.Here,we employed conservation genomics methods to investigate the population dynam-ics of B.opulentus during the recent past and identify the likely environmental factors that may cause population decline.Firstly,we placed the scaffold-level of B.opulentus ref-erence genome sequence onto chromosome-level using Hi-C technique.Then,based on this reference genome and whole-genome resequencing data for 51 B.opulentus samples,we reconstructed the population structure and effective population size(Ne)trajectories of B.opulentus and identified genes that were under positive selection.Our results revealed that the collected B.opulentus samples could be divided into 2 populations,and 1 of them experienced a recent population decline;the declining population also exhibited lower ge-netic diversity and higher inbreeding levels.Genes related to high-temperature tolerance,immune response,and detoxication showed signals of positive selection in the declining population,suggesting that climate warming and pathogen/pesticide exposures may con-tribute to the decline of this B.opulentus population.Taken together,our study provided insights into the demography of B.opulentus populations and highlighted that popula-tions of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.
基金part of the research activities of the operational group,“Animal Genetic Resources”that operates under the auspices of the Agricultural European Innovation Partnership(EIP-AGRI)projectthe European Commission for providing funds for the project.
文摘Local cattle breeds continue to decline in numbers partly due to the use of high performing breeds in advanced production systems where genetic material of elite animals is widely spread. The objective of this study was to assess the within and across breed genetic diversity of the Angler and Red-and-White dual-purpose (DP) cattle breeds applying different inbreeding concepts. Classical and ancestral inbreeding coefficients were computed from pedigree data using the gene dropping method. Effective population size was calculated based on the increase of classical inbreeding, and based on ancestral inbreeding to obtain what was termed as ancestral effective population size. Furthermore, the effective number of founders and ancestors were computed to assess the disequilibrium of founder contribution in the reference populations. The analyses were performed separately for each breed and for a combined dataset. The Angler pedigree was more complete (88%) in the first parental generation but completeness declined with increasing pedigree depth. Average classical inbreeding coefficients of inbred individuals were 2.19%, 1.94% and 2.07%, while average Ballou’s ancestral inbreeding coefficients were 3.69%, 1.39% and 2.21% for the Angler, Red-and-White DP and the combined breed pedigree analyses, respectively. Ancestral history coefficient is a novel coefficient and its estimates were similar and strongly correlated to Ballou’s coefficients (r = 0.99, p < 0.001). The effective population size estimates ranged from 156 to 170 for the classical inbreeding based method, and as low as from 50 to 54 for the ancestral history coefficient based method. The effective number of founders and ancestors ranged from 310 to 532, and 90 to 189, respectively. Our results show that the Red Holstein breed is a key progenitor of the breed populations under study. This highlights cross breeding schemes introduced to improve the milk trait performance of the Angler and Red-and-White DP breeds some decades ago.
