| Summary: | 碩士 === 國立成功大學 === 生物多樣性研究所 === 93 === Flowering is one of the important developmental processes of plants because it is directly related to reproductive success. MADS-box gene family in plants control various aspects of development and reproductive processes including floral formation, LEAFY (LFY) belong to the MADS-box gene. In flowering plant, LEAFY gene determines the transition from the vegetative to the reproductive phase, as LEAFY is both necessary and sufficient for the initiation of individual flowers. In contrast, FLO/LFY genes regulate the first cell division after the formation of zygote in mosses. This study examined the mode of natural selection and effects of other evolutionary forces that shared the evolution of the moss FLO/LFY gene, PpLFY 1. In the PpLFY 1 gene, three lineages were identified in acrocarpous and pleurocarpus mosses. Molecular dating revealed that the PpLFY 1 gene has long existed in mosses about 608-653 MYA, predating the divergence of mosses. Both Ka/Ks and dn/ds ratio are less than 1, revealing that PpLFY 1 gene is under negative selection in mosses, although the Tajima’s d values are mostly nonsignificantly negative. PAML analysis also detected different modes of natural selection along each amino acid sites.
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