PDF(Pubmed)
Abstract：
Polyploidization presents an unusual challenge for species with sex chromosomes, as it can lead to complex combinations of sex chromosomes that disrupt reproductive development. This is particularly true for allopolyploidization between species with different sex chromosome systems. Here, we assemble haplotype-resolved chromosome-level genomes of a female allotetraploid weeping willow (Salix babylonica) and a male diploid S. dunnii. We show that weeping willow arose from crosses between a female ancestor from the Salix-clade, which has XY sex chromosomes on chromosome 7, and a male ancestor from the Vetrix-clade, which has ancestral XY sex chromosomes on chromosome 15. We find that weeping willow has one pair of sex chromosomes, ZW on chromosome 15, that derived from the ancestral XY sex chromosomes in the male ancestor of the Vetrix-clade. Moreover, the ancestral 7X chromosomes from the female ancestor of the Salix-clade have reverted to autosomal inheritance. Duplicated intact ARR17-like genes on the four homologous chromosomes 19 likely have contributed to the maintenance of dioecy during polyploidization and sex chromosome turnover. Taken together, our results suggest the rapid evolution and reversion of sex chromosomes following allopolyploidization in weeping willow.
摘要：
多倍体化对具有性染色体的物种提出了不寻常的挑战，因为它可以导致破坏生殖发育的性染色体的复杂组合。对于具有不同性染色体系统的物种之间的异源多倍体尤其如此。这里,我们组装了雌性异源四倍体垂柳（Salixbabylonica）和雄性二倍体S.dunnii的单倍型解析染色体水平基因组。我们证明垂柳来自柳枝的雌性祖先之间的杂交，7号染色体上有XY性染色体，还有一个来自Vetrix进化枝的男性祖先，在15号染色体上有祖先的XY性染色体。我们发现垂柳有一对性染色体，15号染色体上的ZW，源自Vetrix进化枝雄性祖先的XY性染色体。此外，柳枝雌性祖先的祖先7X染色体已恢复为常染色体遗传。在四个同源染色体19上重复的完整ARR17样基因可能有助于在多倍体化和性染色体周转过程中维持二倍体。一起来看,我们的结果表明，在垂柳中，同种多倍体化后，性染色体的快速进化和逆转。
