High hypomethylation and epigenetic variation in fragmented populations of wild barley (Hordeum brevisubulatum).

摘要

The relationships between epigenetic variation and different environments have being received more attention, however, little is known of the population epigenetic changes by habitat fragmentation (HF). Our previous studies showed higher genetic diversity and differentiation in fragmented populations (FPs) of a wild barley species Hordeum brevisubulatum . In this paper, the effects on the population-epigenetic variation by HF were evaluated using marker methylation-sensitive amplification polymorphism (MSAP). 21 individuals of 5 populations were selected upon the data of AFLP (amplified fragment-length polymorphism) and SSAP (sequence-specific amplification polymorphism). Higher hypomethylation levels were in three FPs (average 3.72%), comparing with two unfragmented populations (UFPs, average 2.67%), and higher epigenetic diversities were also in FPs (0.292 of Nei’s index) than in UFPs (0.249). Epigenetic variations were higher than genetic ones (AFLP and SSAP) within the populations, and individuals were dispersed more in cluster analysis using MSAP data; although most of the individuals belonging to a population were clustered into one group using all markers of MSAP, AFLP, and SSAP. The epigenetic molecular variation was lower between FP and UFP groups (3.09%) comparing with genetic ones (AFLP, 18.13%; SSAP, 13.87%), but higher among populations (23.25%) within the groups than genetic ones (AFLP, 12.69%; SSAP, 13.46%). In addition, epigenetic diversities were minimally correlated with genetic ones, and uncorrelated with geographical distances. Therefore, population epigenetic variation may be more sensitive than genetic one to the HF in wild barley.