Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosom...Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosome turnover. Recent studies have made significant progress in better understanding diversity and conservation of reptile sex chromosomes, with however no reptile master sex determination genes identified. Here we describe an integrated genomics and cytogenetics pipeline,combining probes generated from the microdissected sex chromosomes with transcriptome and genome sequencing to explore the sex chromosome diversity in non-model Australian reptiles. We tested our pipeline on a turtle, two species of geckos, and a monitor lizard. Genes identified on sex chromosomes were compared to the chicken genome to identify homologous regions among the four species. We identified candidate sex determining genes within these regions, including conserved vertebrate sex-determining genes pdgfa,pdgfra amh and wt1, and demonstrated their testis or ovary-specific expression. All four species showed gene-by-gene rather than chromosome-wide dosage compensation. Our results imply that reptile sex chromosomes originated by independent acquisition of sex-determining genes on different autosomes,as well as translocations between different ancestral macro-and microchromosomes.We discuss the evolutionary drivers of the slow differentiation and turnover of reptile sex chromosomes.展开更多
基金supported by the National Natural Science Foundation of China (32170415, 32061130208)Natural Science Foundation of Zhejiang Province (LD19C190001)+6 种基金European Research Council Starting Grant (677696) to Q.Z.supported by an ARC FT (FT110100733)partially supported by ARC DP (DP110102262) led by T.E.University of Canberra Strategic Research Fund awarded to T.E.supported by an ARC DP (DP110102262) led by T.E.supported by NSF (IOS1146820)supported by the University of Canberra postgraduate research scholarships。
文摘Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosome turnover. Recent studies have made significant progress in better understanding diversity and conservation of reptile sex chromosomes, with however no reptile master sex determination genes identified. Here we describe an integrated genomics and cytogenetics pipeline,combining probes generated from the microdissected sex chromosomes with transcriptome and genome sequencing to explore the sex chromosome diversity in non-model Australian reptiles. We tested our pipeline on a turtle, two species of geckos, and a monitor lizard. Genes identified on sex chromosomes were compared to the chicken genome to identify homologous regions among the four species. We identified candidate sex determining genes within these regions, including conserved vertebrate sex-determining genes pdgfa,pdgfra amh and wt1, and demonstrated their testis or ovary-specific expression. All four species showed gene-by-gene rather than chromosome-wide dosage compensation. Our results imply that reptile sex chromosomes originated by independent acquisition of sex-determining genes on different autosomes,as well as translocations between different ancestral macro-and microchromosomes.We discuss the evolutionary drivers of the slow differentiation and turnover of reptile sex chromosomes.
