Key Laboratory for Bio-Resources and Eco-Environment, Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Sciences, Sichuan University, Chengdu 610065, China.
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China.
Proc Natl Acad Sci U S A. 2024 Apr 9;121(15):e2313921121. doi: 10.1073/pnas.2313921121. Epub 2024 Apr 3.
Malvaceae comprise some 4,225 species in 243 genera and nine subfamilies and include economically important species, such as cacao, cotton, durian, and jute, with cotton an important model system for studying the domestication of polyploids. Here, we use chromosome-level genome assemblies from representatives of five or six subfamilies (depending on the placement of ) to differentiate coexisting subgenomes and their evolution during the family's deep history. The results reveal that the allohexaploid Helicteroideae partially derive from an allotetraploid Sterculioideae and also form a component of the allodecaploid Bombacoideae and Malvoideae. The ancestral Malvaceae karyotype consists of 11 protochromosomes. Four subfamilies share a unique reciprocal chromosome translocation, and two other subfamilies share a chromosome fusion. DNA alignments of single-copy nuclear genes do not yield the same relationships as inferred from chromosome structural traits, probably because of genes originating from different ancestral subgenomes. These results illustrate how chromosome-structural data can unravel the evolutionary history of groups with ancient hybrid genomes.
锦葵科包括约 4225 个种，分属于 243 个属和九个亚科，其中包括可可、棉花、榴莲和黄麻等经济上重要的物种，棉花是研究多倍体驯化的重要模式系统。在这里，我们使用来自五个或六个亚科（取决于的位置）代表的染色体水平基因组组装来区分共存的亚基因组及其在家族的深层历史中的进化。结果表明，异源六倍体旋花科部分来自同源四倍体椴树科，也形成了全十倍体梧桐科和锦葵科的组成部分。祖先锦葵科的染色体组型由 11 个原染色体组成。四个亚科共享一个独特的相互易位，另外两个亚科共享一个染色体融合。单拷贝核基因的 DNA 比对不能得出与从染色体结构特征推断出的相同关系，这可能是因为基因来自不同的祖先亚基因组。这些结果说明了染色体结构数据如何揭示具有古老杂交基因组的群体的进化历史。
