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 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.
