Chromosome-length genome assemblies and cytogenomic analyses of pangolins reveal remarkable chromosome counts and plasticity
Chromosome-length genome assemblies and cytogenomic analyses of pangolins reveal remarkable chromosome counts and plasticity
复制标题
DOI：
10.1007/s10577-023-09722-y
复制
发表时间：
2023-04-12
影响因子：
2.6
通讯作者：
Dudchenko，Olga
中科院分区：
文献类型：
--
作者：
Houck，Marlys L.;Koepfli，Klaus-Peter;Dudchenko，Olga
我们首次报道了三种哺乳动物穿山甲的染色体长度的基因组组合：白腹穿山甲、中国穿山甲和舜达穿山甲。令人惊讶的是，我们在这一目中观察到了非凡的核型可塑性，在雌性白腹穿山甲中，报告了劳拉西亚哺乳动物中最多的染色体数量：2N= 114。我们首次对非洲穿山甲进行了核型分析，并报告了白腹穿山甲中的Y常染色体融合，导致雄性穿山甲的2n= 113。我们采用了一种新的策略来确认融合和识别所涉及的常染色体，方法是找到雌性白腹穿山甲基因组中的伪常染色体区域(PAR)，并分析雄性和雌性白腹穿山甲中PAR序列与基因组其余部分之间的3D接触频率。遗传变异分析表明，与中国穿山甲和舜达穿山甲相比，白腹穿山甲具有中等水平的全基因组杂合性，这与历史上有效种群规模的两次适度下降一致。我们的结果揭示了穿山甲基因组生物学的一个显着特征，并突显了对这些独特的濒危哺乳动物进行进一步研究的必要性。
We report the first chromosome-length genome assemblies for three species in the mammalian order Pholidota: the white-bellied, Chinese, and Sunda pangolins. Surprisingly, we observe extraordinary karyotypic plasticity within this order and, in female white-bellied pangolins, the largest number of chromosomes reported in a Laurasiatherian mammal: 2n= 114. We perform the first karyotype analysis of an African pangolin and report a Y-autosome fusion in white-bellied pangolins, resulting in 2n= 113 for males. We employ a novel strategy to confirm the fusion and identify the autosome involved by finding the pseudoautosomal region (PAR) in the female genome assembly and analyzing the 3D contact frequency between PAR sequences and the rest of the genome in male and female white-bellied pangolins. Analyses of genetic variability show that white-bellied pangolins have intermediate levels of genome-wide heterozygosity relative to Chinese and Sunda pangolins, consistent with two moderate declines of historical effective population size. Our results reveal a remarkable feature of pangolin genome biology and highlight the need for further studies of these unique and endangered mammals.