Molecular Ecology and Evolution
Yongmei, Chen , Renchao, Zhou , Suhua, Shi .
Diversifying selection in a mangrove species Rhizophora apiculata revealed by population sequencing .
Mangroves live in extreme intertidal environments and are expected to undergo intense selection pressures. Population genetics approach has the potential to identify genes under selection. In this study, we examined DNA polymorphism and population differentiation in three populations of Rhizophora apiculata from Hainan, China, by sequencing 78 nuclear genes using Illumina technology and the Sanger method. Thirty individuals were pooled for each population and Illumina sequencing called 81, 109 and 77 SNPs, respectively, from these populations. The average theta_w and theta_pi of the three populations were 0.000261, 0.000341, 0.000242, and 0.000302, 0.000372, 0.000262 respectively, which showed the extremely low level of DNA polymorphism within each population. Most genes showed no or low genetic differentiation, while 46 sites from 28 genes exhibited strong differentiation (Fst>0.15). Tajima's D values of 7 genes were significantly larger than zero at the 95% confidence level. We further used Sanger sequencing to obtain haplotypes of about 20 individuals in each population. In Sanya River population, two divergent haplotypes at three genes were found while there was obvious deficiency of heterozygotes. Both genetic bottleneck and population admixture model could not account for the observed patterns, and we suggested that these genes may be affected by diversifying selection. This may be associated with the heterogeneous environments in Sanya River. Our study provides a probable scenario of plant adaptation to extreme and heterogeneous environments by diversifying selection in some specific genes. The candidate genes underlying selection are worth studying further at the physiological and ecological levels.
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1 - Sun Yat-sen University, College of Life Science, xingangxilu 135, Guangzhou,Guangdong, Guangzhou, GD, 510275, China
Presentation Type: Oral Paper:Papers for Topics
Location: Westminster Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 3:45 PM