Genome complexity reduction and high throughput sequencing of green iguana (Iguana iguana) cause a paradigm shift in understanding sex chromosomal linkages on homomorphic X and Y sex chromosomes

Most lizards in the Superfamily Iguanoidea have an XX/XY sex determination system in which sex chromosomal linkage has homology with chicken (Gallus gallus) chromosome 15 (GGA15); however, sex chromosome genomics remains largely unexplored due to the presence of homomorphic sex chromosomes in many species. Recent advances in high-throughput sequencing with genome complexity reduction now provide an effective approach to identify sex-specific loci in both single nucleotide polymorphisms (SNPs) and restriction fragment presence/absence (PA), and a better understanding of sex chromosome dynamics in this lineage. Here, we applied Diversity Arrays Technology (DArTseq™) in 29 phenotypic sex assignments of green iguana (Iguana iguana). We confirmed a male heterogametic (XX/XY) sex determination mode in this species, identifying 29 perfectly sex-linked SNP/PA loci and 164 moderately sex-linked SNP/PA loci, likely serving as evidence indicative of XY recombination. 3 loci from perfectly sex-link...鬣蜥总科（Iguanoidea）的多数蜥蜴类群均采用XX/XY性别决定系统，其性染色体连锁区域与鸡（原鸡Gallus gallus）15号染色体（GGA15）具有同源性；但由于多数物种存在同形性染色体，目前该类群的性染色体基因组学研究仍有待深入探索。近年来，搭载基因组复杂度降低策略的高通量测序技术取得进展，为从单核苷酸多态性（SNPs）和限制性片段有无（PA）两类标记中鉴定性别特异性位点提供了有效手段，也有助于我们更清晰地理解该演化支的性染色体动态变化。本研究针对29例经表型鉴定性别的绿鬣蜥（Iguana iguana）样本，应用了多样性阵列技术（DArTseq™）。研究确认了该物种的雄性异配型（XX/XY）性别决定模式，共鉴定出29个完全性连锁的SNP/PA位点以及164个中度性连锁的SNP/PA位点，这些位点或可作为XY重组的佐证证据。3个完全性连锁的位点来自……