The evolution of the SEPALLATA subfamily of MADS-Box genes:: A preangiosperm origin with multiple duplications throughout angiosperm history
The evolution of the SEPALLATA subfamily of MADS-Box genes:: A preangiosperm origin with multiple duplications throughout angiosperm history
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DOI：
10.1534/genetics.104.037770
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发表时间：
2005-04-01
期刊：
影响因子：
3.3
通讯作者：
Ma, H
中科院分区：
文献类型：
--
作者：
Zahn, LM;King, HZ;Ma, H
SEPALLATA（SEP）MADS-盒亚家族的成员需要指定的“花的状态”，有助于花器官和分生组织的身份。SEP基因在裸子植物中尚未发现，可能起源于被子植物的分支。因此，功能和进化研究都表明SEP基因可能对花的起源至关重要。为了深入了解SEP基因的进化，我们从植物中分离了9个占据重要位置的基因。SEP序列的系统发育分析表明，在该亚家族的进化过程中发生了一些基因重复，为功能分歧提供了潜在的机会。第一次重复发生在现存被子植物起源之前，导致了AGL 2/3/4和AGL 9分支。在真双子叶植物和单子叶植物的这些分支中发生了随后的复制。第一个SEP重复的时间大约与DEFICIENS/GLOBOSA和AGAMOUS MADS盒亚科的重复一致，这可能是由于现存被子植物祖先的全基因组重复或多个独立的重复事件。不管基因复制的机制如何，这些成对的复制转录因子提供了遗传相互作用的新可能性，这可能在花的起源中很重要。
Members of the SEPALLATA (SEP) MADS-box subfamily are required for specifying the "floral state" by contributing to floral organ and meristem identity. SEP genes have riot been detected in gymnosperms and seem to have originated since the lineage leading to extant angiosperms diverged from extant gymnosperms. Therefore, both functional and evolutionary studies suggest that SEP genes may have been critical for the origin of the flower. To gain insights into the evolution of SEP genes, we isolated nine genes from plants that occupy phylogenetically important positions. Phylogenetic analyses of SEP sequences show that several gene duplications occurred during the evolution of this subfamily, providing potential opportunities for functional divergence. The first duplication occurred prior to the origin of the extant angiosperms, resulting in the AGL2/3/4 and AGL9 clades. Subsequent duplications occurred within these clades in the eudicots and monocots. The timing of the first SEP duplication approximately coincides with duplications in the DEFICIENS/GLOBOSA and AGAMOUS MADS-box subfamilies, which may have resulted from either a proposed genome-wide duplication in the ancestor of extant angiosperms or multiple independent duplication events. Regardless of the ,mechanism of gene duplication, these pairs of duplicate transcription factors provided new possibilities of genetic interactions that may have been important in the origin of the flower.