A near-complete genome assembly of the bearded dragon Pogona vitticeps provides insights into the origin of Pogona sex chromosomes

作者：Qunfei Guo, Youliang Pan, Wei Dai, Fei Guo, Zeng Tao, Wanyi Chen, Yaping Mi, Yanshu Zhang, Shuaizhen Shi, Wei Jiang, Huimin Cai, Beiying Wu, Yang Zhou, Ying Wang, Chentao Yang, Xiao Shi, Yan Xu, Junyi Chen, Chongyang Cai, Jingnan Yang, Xun Xu, Gu Ying, Yuliang Dong, Qiye Li · 发表于：GigaScience · 年份：2025 · DOI：10.1093/gigascience/giaf079 · 被引用次数：7 · 研究领域：Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities、Genomics and Phylogenetic Studies、Turtle Biology and Conservation

BACKGROUND: Vertebrate sex is typically determined either by genetic factors, such as sex chromosomes, or by environmental cues like temperature. Therefore, the agamid dragon lizard Pogona vitticeps is remarkable in this regard, as it exhibits both ZZ/ZW genetic and temperature-dependent sex determination. However, complete sequence and full gene content of P. vitticeps sex chromosomes remain unclear, hindering the investigation of sex-determining cascade in this model lizard. RESULTS: Using CycloneSEQ and DNBSEQ sequencing technologies, we generated a near-complete chromosome-scale genome assembly for a ZZ male P. vitticeps. Compared with previous reference genome (GCF_900067755.1/Pvi1.1), this ∼1.8-Gb new assembly displayed >5,700-fold improvement in contiguity (contig N50: 202.5 Mb vs. 35.5 kb) and achieved complete chromosome anchoring (16 vs. 13,749 scaffolds). We found that over 80% of the P. vitticeps Z chromosome remains as a pseudo-autosomal region, where recombination is not suppressed. The sexually differentiated region (SDR) is small and occupied mostly by transposons, yet it aggregates genes involved in male development, such as AMH, AMHR2, and BMPR1A. Finally, by tracking the evolutionary origin and developmental expression of SDR genes, we proposed a model for the origin of P. vitticeps sex chromosomes that considered the Z-linked AMH as the master sex-determining gene. CONCLUSIONS: In this study, we fully characterized the Z sex chromosome of P. vitticeps, ide...