The primer pair sex1/sex2,which can be widely applied for sex identification in Galliform species,was used to determine the sex of 17 Passeriform species.As CHD-W fragments tended to be preferentially amplified,which ...The primer pair sex1/sex2,which can be widely applied for sex identification in Galliform species,was used to determine the sex of 17 Passeriform species.As CHD-W fragments tended to be preferentially amplified,which may cause unnecessary misidentification in bird species with little difference between CHD-Z and CHD-W,we modified sex1 and sex2,obtaining sex1' and sex-mix respectively.Primer sets were then recombined to conduct sex identification.After testing several Passeriforme birds of known sex,we found that the primer pair sex1'/sex2 was better at limiting the preferential amplification of CHD-W fragments.As they are being frequently used in sex allocation study of Aegithalos concinnus and song learning research of Lonchura striata,we can expect more applications of this primer pair to further studies in Passeriformes.展开更多
Principle, research, and problems of techniques for sex identification of early embryo of livestock were discussed in detail from aspects of main ways for sex control, main methods for sex identification of early embr...Principle, research, and problems of techniques for sex identification of early embryo of livestock were discussed in detail from aspects of main ways for sex control, main methods for sex identification of early embryo, and application of sex identification in livestock production. And development prospects were expected.展开更多
Sex determining gene primers of Oriental White Stork were used to amplify sex-linked gene of the Red-crowned Crane′s W chromosome-specific by PCR for sex identification. The sexes of 7 couples of grown Red-crowned Cr...Sex determining gene primers of Oriental White Stork were used to amplify sex-linked gene of the Red-crowned Crane′s W chromosome-specific by PCR for sex identification. The sexes of 7 couples of grown Red-crowned Cranes and 15 youngs were identified. Through DNA sequence analysis, the identity is 94.77% between Red-crowned Crane and Oriental White Stork. The results of this study suggest that the application of the polymerase chain reaction technique is practicable for determining sex in the Red-crowned Crane.展开更多
The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked m...The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked molecular markers(SyGI[Shy Girl],FrBy[Friendly Boy],and SmY1)in sex identification was evaluated in various Actinidia species.The selected marker products were subsequently cloned and sequenced in six wild Actinidia species.Ninety-six wild A.chinensis chinensis accessions and 74 A.chinensis deliciosa accessions,most of which were wild,with only one cultivated,were used for comprehensive primer validation.Thirty-three juvenile A.chinensis chinensis hybrid seedlings were used for practical application tests.The results showed that the marker SyGI accurately identified the sex of 20 samples from six Actinidia species and 96 A.chinensis chinensis accessions with 100%reliability.For Actinidia chinensis deliciosa,the identification accuracy reached 98.65%.Sequence analysis revealed that SyGI shared the highest similarity with the male-specific genomic region.Furthermore,SyGI achieved 100%accuracy in identifying the sex of 33 juvenile A.chinensis chinensis individuals.The findings confirm that the SyGI marker possesses high accuracy,strong specificity,and broad applicability,making it a valuable tool for kiwifruit breeding programs.The cloned sequences from wild Actinidia species also provide important references for future research on the mechanisms of sexual evolution and determination.展开更多
By using silkworms,Bombyx mori,fluorescent cocoon sex identification(FCSI)as an experimental material,direct fluorescence spectrometry of the cocoon surface indicates that the fluorescent color of silkworm cocoons is ...By using silkworms,Bombyx mori,fluorescent cocoon sex identification(FCSI)as an experimental material,direct fluorescence spectrometry of the cocoon surface indicates that the fluorescent color of silkworm cocoons is made up of two peaks of yellow and blue-purple fluorescence emission.The fluorescent difference between male and female cocoons is attributed to the differential absorption of yellow fluorescent substances by the midgut tissue of 5th instar female silkworms.Thin layer chromatography(TLC)and fluorescent spectra indicate that blue-purple fluorescent substances are composed of at least five blue-purple fluorescent pigments,and yellow fluorescent substances are made up of at least three.UV spectra and AlCl3 color reaction show that the three fluorescent yellow pigments are flavonoids or their glycosides.Silkworm FCSI is due to selective absorption or accumulation of the yellow fluorescent pigments by the posterior midgut cells of female 5th instar larvae.The cells of the FCSI silkworm midgut,especially the cylinder intestinal cells of the posterior midgut have a component which is a yellow fluorescent pigment-specific binding protein that may be vigorously expressed in the 5th instar larvae.展开更多
In this study, a protocol was developed to identify the sex of earlier embryos of chicken （♂）-quail （♀） hybrids and successfully tested the sex proportion of each period （66-120 h）. We acquired cross bred eggs...In this study, a protocol was developed to identify the sex of earlier embryos of chicken （♂）-quail （♀） hybrids and successfully tested the sex proportion of each period （66-120 h）. We acquired cross bred eggs by artificial insemination, hatched them in the same batch according to the standard hatching condition of chicken, and collected earlier living embryos at 66, 72, 78, 84, 90, 96, 102, 108, 114, and 120 h randomly. We adopted RT-PCR protocol and multiple PCR, made the known sex quail as the external control, employed fl-actin as the internal control, and used primers that were designed according to conservative area of gene Wpkci of quail to identify the sex of earlier hybrid embryos. The results indicated that the primer of Wpkci can be used to identify the sex of hybrid embryos accurately; there were more male than female in earlier embryos, the sex proportion of earlier embryos compared with academic numerical value was significantly different （P〈0.01）, and there was no difference between different periods （P〉0.05）. In the present study, we concluded that a simple, fast, credible and stable protocol to identify the sex of earlier hybrids embryos had been established by using primer of Wpkci; in earlier embryos, the death rate of female was higher than that of male and there was no fluctuant peak.展开更多
Background:Various methods are used in forensic odontology for the purpose of sex and personal identification.Some of them include cheiloscopy,rugoscopy,mandibular measurements,and study of paranasal sinuses.In our st...Background:Various methods are used in forensic odontology for the purpose of sex and personal identification.Some of them include cheiloscopy,rugoscopy,mandibular measurements,and study of paranasal sinuses.In our study,we have used maxillary sinus as an aid in sex identification.For this purpose,we have evaluated the morphometric and volumetric measurements of the maxillary sinus using a 3-Dimensional imaging modality,Cone Beam Computed Tomography.Aims and Objectives:Sex and age identification are important in the process of identification of both the living and the dead.Hence,this transverse retrospective study was done to appraise the precision of the dimensions and volume of the maxillary sinus to aid in sex and age identification.Material and Methods:Eighty full Field of View(FOV)Cone-Beam Computed Tomography(CBCT)images were retrieved from the archives which were matched with age and sex.The maxillary sinuses on either side were measured mediolaterally in the axial section and supero-inferiorly in the coronal section.The volumetric analysis of the sinus was done in the sagittal section.The sex was classified using discriminant function analysis and the differences were compared using independent t-test.The differences with age were analyzed using one-way ANOVA.Results:Independent t-test was done for comparison of the sinuses between both sexes.Maxillary sinuses measurements were larger among the males both superior-inferiorly on either side(P<0.001)and mediolaterally on the right(P<0.049)showed statistically significant values.A significant correlation existed while comparing the maxillary sinus volume among both the sexes on either side(P<0.001 and<0.002 in the case of right and left respectively).On comparing the supero-inferior and mediolateral measurements and the maxillary sinus volume on either side among the various age groups,the values were statistically insignificant.Present study shows that the maxillary sinus measurements using Cone-beam computed tomography were diagnostic in the identification of sex but not in age estimation and can be used in forensic dentistry.展开更多
The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinati...The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinations were used to detect the genome DNA bulks of the female and male porpoises, and one sex-related AFLP marker was finally obtained. The marker can be applied to sex identification, and provides a base for further cloning of sex-related genes and analyzing of Y chromosome haplotypes of the Yangtze finless porpoise.展开更多
The overall sex ratio of offspring （dead embryos and hatch chicks） from all the fertilized eggs of 140 hens collected for 30 days was studied using duplex PCR of certain fragments of sex chromosomes. Additional 894 ...The overall sex ratio of offspring （dead embryos and hatch chicks） from all the fertilized eggs of 140 hens collected for 30 days was studied using duplex PCR of certain fragments of sex chromosomes. Additional 894 dead embryos over a period of 21 days of incubation were also investigated to verify the sex ratio of the dead embryos. The sex of the early dead embryos was identified using this molecular sexing technique. The sex ratio of the hatch chicks and the total offspring of the hens investigated in this experiment did not differ from the expected sex ratio （i.e., 1：1）., However, the number of female dead embryos was significantly more than that of males. The data indicated that the different physiologic function of males and females contributed to female-biased mortality during incubation. It was also found by further analysis that the sex ratios of the offspring of some hens were significantly biased to female or male over the period investigated, which suggested that the sex ratio of offspring might be influenced by the maternal condition to some degrees.展开更多
A new method for detecting the sequence differences of duck Chromo-helicase-DNA-Binding 1 （ CHD1 ） genes on sex chromosomes Z and W was established by amplifying DNA fragment length poly morphism, which aimed to sol...A new method for detecting the sequence differences of duck Chromo-helicase-DNA-Binding 1 （ CHD1 ） genes on sex chromosomes Z and W was established by amplifying DNA fragment length poly morphism, which aimed to solve some technical problems, such as the sex identification with nondamage, the misclassifc rate of artificial sex identification during embryonic period, and the injury caused by anal reversal identification method during neonatal period. The im- proved sex identification method was developed by DNA amplified fragment length polymorphism by using CHD1 gene sequence in bird. The sex identification PCR primers YPF/YPR were used, and the PCR product was cloned, sequenced and blasted; and the effectiveness and accuracy of this method were verified through liv- ing examples. 2% agarose gel electrophoresis was used to distinguish 495 bp CHD1-Z and 351 bp CHD1-W obtained by primer YPF/YPR. The female （ZW） dis- played two visible bands; while male （ZZ） had only one single band. It was proved that this method for detecting the sequence differences of duck CHD1 gene was visual and reliable, and the molecular marker provided was effective and precise in the sex molecular biological identification of domesticated duck in China.展开更多
To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells wer...To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1. 98±0. 28× 10-5. There was no significant difference between the first and second trimester (P>0. 05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.展开更多
Desmans belong to the subfamily Desmaninae,which are members of the family Talpidae.Desmans and moles show limited sexual dimorphism,making unclear sex discrimination by phenotypic assessment.The Iberian desman(Galemy...Desmans belong to the subfamily Desmaninae,which are members of the family Talpidae.Desmans and moles show limited sexual dimorphism,making unclear sex discrimination by phenotypic assessment.The Iberian desman(Galemys pyrenaicus)is an endangered species with a severe population decline.Knowledge of sex and sex ratio is essential for conservation and management.Based on these arguments and although previous conventional PCR studies amplifying DBX/DBY genes were relatively successful in sexing the desman,high-resolution sex-specific PCR has been requested.All these reasons encouraged us to develop new species-specific RT-qPCR assays by TaqMan probes to determine the sex in desman,especially with genetic material from noninvasive samples.Accordingly,efficiency,limit of detection(LOD),specificity,and DNA analysis from faeces were verified.The target genes DBX and DBY were amplified with gDNA from both sexes,with Y-chromosome consistently absent in the female.Despite themodest efficiency,regression analysis(R2>0.999)indicated a linear range of the DBX and DBY assays extending from 20 to 0.2 ng/μL DNA.LOD analyses estimated that twice as much gDNA was needed in males as in females for DBX detection.Paradoxically,the Y-chromosome required three times as much gDNA as the X-chromosome using a male sample.Therefore,an unexpected dosage imbalance in the genome in favour of the X chromosome was discussed in light of an apparent multicopy nature of the DBX gene and with a sexing success rate of 49.9%of the non-invasive samples,supporting Fisher’s principle for the mammalian XX/XY sex system,as expected.展开更多
基金supported by the National Natural Science Foundation of China (Nos.30570234,30330050)
文摘The primer pair sex1/sex2,which can be widely applied for sex identification in Galliform species,was used to determine the sex of 17 Passeriform species.As CHD-W fragments tended to be preferentially amplified,which may cause unnecessary misidentification in bird species with little difference between CHD-Z and CHD-W,we modified sex1 and sex2,obtaining sex1' and sex-mix respectively.Primer sets were then recombined to conduct sex identification.After testing several Passeriforme birds of known sex,we found that the primer pair sex1'/sex2 was better at limiting the preferential amplification of CHD-W fragments.As they are being frequently used in sex allocation study of Aegithalos concinnus and song learning research of Lonchura striata,we can expect more applications of this primer pair to further studies in Passeriformes.
文摘Principle, research, and problems of techniques for sex identification of early embryo of livestock were discussed in detail from aspects of main ways for sex control, main methods for sex identification of early embryo, and application of sex identification in livestock production. And development prospects were expected.
文摘Sex determining gene primers of Oriental White Stork were used to amplify sex-linked gene of the Red-crowned Crane′s W chromosome-specific by PCR for sex identification. The sexes of 7 couples of grown Red-crowned Cranes and 15 youngs were identified. Through DNA sequence analysis, the identity is 94.77% between Red-crowned Crane and Oriental White Stork. The results of this study suggest that the application of the polymerase chain reaction technique is practicable for determining sex in the Red-crowned Crane.
基金funded by Sichuan Science and Technology Program,grant numbers 2021YFYZ0010,2023YFH0006,2025YFHZ0295The Basic Research Program of Sichuan Provincial Research Institutes,grant numbers 2024JDKY0001 and 2023JDKY0001.
文摘The genus Actinidia is primarily functionally dioecious,and early sex identification plays a crucial role in improving breeding efficiency and reducing production costs.In this study,the accuracy of three sex-linked molecular markers(SyGI[Shy Girl],FrBy[Friendly Boy],and SmY1)in sex identification was evaluated in various Actinidia species.The selected marker products were subsequently cloned and sequenced in six wild Actinidia species.Ninety-six wild A.chinensis chinensis accessions and 74 A.chinensis deliciosa accessions,most of which were wild,with only one cultivated,were used for comprehensive primer validation.Thirty-three juvenile A.chinensis chinensis hybrid seedlings were used for practical application tests.The results showed that the marker SyGI accurately identified the sex of 20 samples from six Actinidia species and 96 A.chinensis chinensis accessions with 100%reliability.For Actinidia chinensis deliciosa,the identification accuracy reached 98.65%.Sequence analysis revealed that SyGI shared the highest similarity with the male-specific genomic region.Furthermore,SyGI achieved 100%accuracy in identifying the sex of 33 juvenile A.chinensis chinensis individuals.The findings confirm that the SyGI marker possesses high accuracy,strong specificity,and broad applicability,making it a valuable tool for kiwifruit breeding programs.The cloned sequences from wild Actinidia species also provide important references for future research on the mechanisms of sexual evolution and determination.
基金supported by the National High Technology Research and Development Program(Grant No.2006AA10A118)the Earmarked Fund for Modern Agro-industry Technology Research System,China
文摘By using silkworms,Bombyx mori,fluorescent cocoon sex identification(FCSI)as an experimental material,direct fluorescence spectrometry of the cocoon surface indicates that the fluorescent color of silkworm cocoons is made up of two peaks of yellow and blue-purple fluorescence emission.The fluorescent difference between male and female cocoons is attributed to the differential absorption of yellow fluorescent substances by the midgut tissue of 5th instar female silkworms.Thin layer chromatography(TLC)and fluorescent spectra indicate that blue-purple fluorescent substances are composed of at least five blue-purple fluorescent pigments,and yellow fluorescent substances are made up of at least three.UV spectra and AlCl3 color reaction show that the three fluorescent yellow pigments are flavonoids or their glycosides.Silkworm FCSI is due to selective absorption or accumulation of the yellow fluorescent pigments by the posterior midgut cells of female 5th instar larvae.The cells of the FCSI silkworm midgut,especially the cylinder intestinal cells of the posterior midgut have a component which is a yellow fluorescent pigment-specific binding protein that may be vigorously expressed in the 5th instar larvae.
文摘In this study, a protocol was developed to identify the sex of earlier embryos of chicken （♂）-quail （♀） hybrids and successfully tested the sex proportion of each period （66-120 h）. We acquired cross bred eggs by artificial insemination, hatched them in the same batch according to the standard hatching condition of chicken, and collected earlier living embryos at 66, 72, 78, 84, 90, 96, 102, 108, 114, and 120 h randomly. We adopted RT-PCR protocol and multiple PCR, made the known sex quail as the external control, employed fl-actin as the internal control, and used primers that were designed according to conservative area of gene Wpkci of quail to identify the sex of earlier hybrid embryos. The results indicated that the primer of Wpkci can be used to identify the sex of hybrid embryos accurately; there were more male than female in earlier embryos, the sex proportion of earlier embryos compared with academic numerical value was significantly different （P〈0.01）, and there was no difference between different periods （P〉0.05）. In the present study, we concluded that a simple, fast, credible and stable protocol to identify the sex of earlier hybrids embryos had been established by using primer of Wpkci; in earlier embryos, the death rate of female was higher than that of male and there was no fluctuant peak.
文摘Background:Various methods are used in forensic odontology for the purpose of sex and personal identification.Some of them include cheiloscopy,rugoscopy,mandibular measurements,and study of paranasal sinuses.In our study,we have used maxillary sinus as an aid in sex identification.For this purpose,we have evaluated the morphometric and volumetric measurements of the maxillary sinus using a 3-Dimensional imaging modality,Cone Beam Computed Tomography.Aims and Objectives:Sex and age identification are important in the process of identification of both the living and the dead.Hence,this transverse retrospective study was done to appraise the precision of the dimensions and volume of the maxillary sinus to aid in sex and age identification.Material and Methods:Eighty full Field of View(FOV)Cone-Beam Computed Tomography(CBCT)images were retrieved from the archives which were matched with age and sex.The maxillary sinuses on either side were measured mediolaterally in the axial section and supero-inferiorly in the coronal section.The volumetric analysis of the sinus was done in the sagittal section.The sex was classified using discriminant function analysis and the differences were compared using independent t-test.The differences with age were analyzed using one-way ANOVA.Results:Independent t-test was done for comparison of the sinuses between both sexes.Maxillary sinuses measurements were larger among the males both superior-inferiorly on either side(P<0.001)and mediolaterally on the right(P<0.049)showed statistically significant values.A significant correlation existed while comparing the maxillary sinus volume among both the sexes on either side(P<0.001 and<0.002 in the case of right and left respectively).On comparing the supero-inferior and mediolateral measurements and the maxillary sinus volume on either side among the various age groups,the values were statistically insignificant.Present study shows that the maxillary sinus measurements using Cone-beam computed tomography were diagnostic in the identification of sex but not in age estimation and can be used in forensic dentistry.
文摘The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism (AFLP) technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinations were used to detect the genome DNA bulks of the female and male porpoises, and one sex-related AFLP marker was finally obtained. The marker can be applied to sex identification, and provides a base for further cloning of sex-related genes and analyzing of Y chromosome haplotypes of the Yangtze finless porpoise.
文摘The overall sex ratio of offspring （dead embryos and hatch chicks） from all the fertilized eggs of 140 hens collected for 30 days was studied using duplex PCR of certain fragments of sex chromosomes. Additional 894 dead embryos over a period of 21 days of incubation were also investigated to verify the sex ratio of the dead embryos. The sex of the early dead embryos was identified using this molecular sexing technique. The sex ratio of the hatch chicks and the total offspring of the hens investigated in this experiment did not differ from the expected sex ratio （i.e., 1：1）., However, the number of female dead embryos was significantly more than that of males. The data indicated that the different physiologic function of males and females contributed to female-biased mortality during incubation. It was also found by further analysis that the sex ratios of the offspring of some hens were significantly biased to female or male over the period investigated, which suggested that the sex ratio of offspring might be influenced by the maternal condition to some degrees.
基金Supported by the National Natural Science Foundation of China(31172194)The Science and Technology Support Program of Jiangsu Province(BE2011329)The Variety Innovation Project of Modern Agriculture(CX(11)1030)
文摘A new method for detecting the sequence differences of duck Chromo-helicase-DNA-Binding 1 （ CHD1 ） genes on sex chromosomes Z and W was established by amplifying DNA fragment length poly morphism, which aimed to solve some technical problems, such as the sex identification with nondamage, the misclassifc rate of artificial sex identification during embryonic period, and the injury caused by anal reversal identification method during neonatal period. The im- proved sex identification method was developed by DNA amplified fragment length polymorphism by using CHD1 gene sequence in bird. The sex identification PCR primers YPF/YPR were used, and the PCR product was cloned, sequenced and blasted; and the effectiveness and accuracy of this method were verified through liv- ing examples. 2% agarose gel electrophoresis was used to distinguish 495 bp CHD1-Z and 351 bp CHD1-W obtained by primer YPF/YPR. The female （ZW） dis- played two visible bands; while male （ZZ） had only one single band. It was proved that this method for detecting the sequence differences of duck CHD1 gene was visual and reliable, and the molecular marker provided was effective and precise in the sex molecular biological identification of domesticated duck in China.
文摘To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1. 98±0. 28× 10-5. There was no significant difference between the first and second trimester (P>0. 05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.
基金supported by the LIFE+Desmania Project(LI-FE11/NAT/ES/000691)Programa para la recuperación y conservación de Galemys pyrenaicus y su hábitat en Castilla y León y Extremadura and the project 0620_BIOTRANS_4_E,which is co-financed by the European Regional Development Fund(FEDER)through the Interreg Cooperation Programme INTERREG V-A Spain-Portugal(POCTEP 2014-2020).
文摘Desmans belong to the subfamily Desmaninae,which are members of the family Talpidae.Desmans and moles show limited sexual dimorphism,making unclear sex discrimination by phenotypic assessment.The Iberian desman(Galemys pyrenaicus)is an endangered species with a severe population decline.Knowledge of sex and sex ratio is essential for conservation and management.Based on these arguments and although previous conventional PCR studies amplifying DBX/DBY genes were relatively successful in sexing the desman,high-resolution sex-specific PCR has been requested.All these reasons encouraged us to develop new species-specific RT-qPCR assays by TaqMan probes to determine the sex in desman,especially with genetic material from noninvasive samples.Accordingly,efficiency,limit of detection(LOD),specificity,and DNA analysis from faeces were verified.The target genes DBX and DBY were amplified with gDNA from both sexes,with Y-chromosome consistently absent in the female.Despite themodest efficiency,regression analysis(R2>0.999)indicated a linear range of the DBX and DBY assays extending from 20 to 0.2 ng/μL DNA.LOD analyses estimated that twice as much gDNA was needed in males as in females for DBX detection.Paradoxically,the Y-chromosome required three times as much gDNA as the X-chromosome using a male sample.Therefore,an unexpected dosage imbalance in the genome in favour of the X chromosome was discussed in light of an apparent multicopy nature of the DBX gene and with a sexing success rate of 49.9%of the non-invasive samples,supporting Fisher’s principle for the mammalian XX/XY sex system,as expected.
