The Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, State Conservation Center for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Genome Biol Evol. 2018 Sep 1;10(9):2168-2177. doi: 10.1093/gbe/evy174.
The giant panda (Ailuropoda melanoleuca) is popular around the world and is widely recognized as a symbol of nature conservation. A draft genome of the giant panda is now available, but its Y chromosome has not been sequenced. Y chromosome data are necessary for study of sex chromosome evolution, male development, and spermatogenesis. Thus, in the present study, we sequenced two parts of the giant panda Y chromosome utilizing a male giant panda fosmid library. The sequencing data were assembled into two contigs, each ∼100 kb in length with no gaps, providing high-quality resources for studying the giant panda Y chromosome. Annotation and transposable element comparison indicates varied evolutionary pressure in different regions of the Y chromosome. Two genes, zinc finger protein, Y-linked (ZFY) and lysine demethylase 5D (KDM5D), were annotated and gene conversion was observed for ZFY exon 7. Phylogenetic analysis also revealed that this gene conversion event happened independently in multiple mammalian lineages, indicating a putative mechanism to maintain the function of this particular gene on the Y chromosome. Furthermore, a transposition event, discovered through comparative alignment with the giant panda X chromosome sequence, may be involved in the process of gaining new genes on the Y chromosome. Thus, these newly obtained Y chromosome sequences provide valuable insights into the genomic patterns of the giant panda.
大熊猫（Ailuropoda melanoleuca）在世界各地广受欢迎，被广泛认为是自然保护的象征。目前已经获得了大熊猫的基因组草图，但尚未对其 Y 染色体进行测序。Y 染色体数据对于研究性染色体进化、雄性发育和精子发生是必要的。因此，在本研究中，我们利用雄性大熊猫fosmid 文库对大熊猫 Y 染色体的两个部分进行了测序。测序数据组装成两个连续序列，每个序列约 100kb 长，没有缺口，为研究大熊猫 Y 染色体提供了高质量的资源。注释和转座元件比较表明，Y 染色体不同区域受到不同的进化压力。注释了两个基因，锌指蛋白，Y 连锁（ZFY）和赖氨酸去甲基酶 5D（KDM5D），并观察到 ZFY 外显子 7 的基因转换。系统发育分析还表明，这种基因转换事件在多个哺乳动物谱系中独立发生，表明了一种维持 Y 染色体上特定基因功能的潜在机制。此外，通过与大熊猫 X 染色体序列的比较比对发现的转位事件，可能参与了 Y 染色体上新基因的获得过程。因此，这些新获得的 Y 染色体序列为研究大熊猫的基因组模式提供了有价值的见解。
