Gubitz Thomas, Caldwell Ailsa, Hudson Andrew
Institute of Cell and Molecular Biology, University of Edinburgh.
Mol Biol Evol. 2003 Sep;20(9):1537-44. doi: 10.1093/molbev/msg166. Epub 2003 Jun 27.
The CYCLOIDEA (CYC) and DICHOTOMA (DICH) genes encode related TCP transcription factors that control floral asymmetry in Antirrhinum majus. Analysis of sequences from relatives of Antirrhinum suggested that CYC and DICH arose from a gene duplication in an ancestor of the tribe Antirrhineae and have subsequently evolved at similar rates. Coding regions outside the conserved functional TCP and R domains differed by numerous indels, suggesting rapid evolution and low constraint on amino acid sequence. An analysis of variability within the genus Antirrhinum revealed very similar CYC alleles in 17 representative species, consistent with most of the species having diverged within the last 1 myr. Whereas substitution mutations appear to have accumulated constantly, one Antirrhinum CYC allele provided evidence for sporadic and rapid accumulation of insertion mutations.
CYCLOIDEA（CYC）基因和DICHOTOMA（DICH）基因编码相关的TCP转录因子，这些因子控制金鱼草的花不对称性。对金鱼草亲属的序列分析表明，CYC和DICH起源于金鱼草族祖先中的一次基因复制，随后以相似的速率进化。保守的功能性TCP和R结构域之外的编码区域因众多插入缺失而不同，这表明氨基酸序列的进化迅速且受到的限制较低。对金鱼草属内变异性的分析显示，17个代表性物种中的CYC等位基因非常相似，这与大多数物种在过去100万年中分化一致。虽然替换突变似乎一直在积累，但一个金鱼草CYC等位基因提供了插入突变偶尔快速积累的证据。
