Phylogeny, transposable element and sex chromosome evolution of the basal lineage of birds. Palaeognathae (ratites and tinamous)

Sex chromosomes of mammals and most birds are heteromorphic, while those of many paleognaths (ratites and tinamous) are inexplicably homomorphic. To dissect the mechanisms underlying the different tempo of sex chromosome evolution, we produced high-quality genomes of 12 paleognathous species, and reconstructed their phylogeny based on alignments of the non-coding sequences extending to nearly 40% of the genome.

哺乳动物与多数鸟类的性染色体均为异形染色体（heteromorphic），而多数古颚总目（Paleognathae，涵盖平胸总目Ratitae与䳍形目Tinamiformes）类群的性染色体却呈现出令人费解的同形特征。为解析性染色体演化速率差异背后的分子机制，本研究组装得到12种古颚类鸟类的高质量基因组，并基于覆盖基因组近40%区域的非编码序列（non-coding sequences）比对结果，重构了该类群的系统发育关系。