Mitochondrial DNA diversity of the vulnerable Chinese Egret (Egretta eulophotes) from China

The genetic diversity and population structure of the vulnerable Chinese Egret (Egretta eulophotes) were surveyed in the present study from three archipelagoes that cover the most southerly to the very northerly parts of the Chinese distribution range of this species, using a 433-bp fragment of the mitochondrial control region (CR). Among 90 individual samples, 31 different haplotypes were defined by 30 polymorphic sites. Overall haplotype diversity, nucleotide diversity and mean sequence divergence (p-distance) of this egret were 0.920, 0.0088 and 1.11%, respectively. NJ tree and parsimony network for the CR haplotypes of the Chinese Egret showed little genetic structure, and analysis of molecular variance indicated low but significant genetic differentiation (haplotype-based I broken vertical bar(ST) = 0.03267, P < 0.05 and distance-based I broken vertical bar(ST) = 0.04194, P < 0.05) among populations. The significant Fu's F (S) tests (Fu's F (S) = -16.946, P < 0.01) and mismatch distribution analysis (tau = 4.463, SSD = 0.0081, P = 0.12) suggested that the low genetic differentiation and little geographical structure of the genetic differentiation might be explained by the population expansion. The Mantel test (haplotype-based F (ST), r = 0.639, P = 0.34 and distance-based F (ST), r = 0.947, P = 0.15) suggest that the significant genetic differentiation among populations was likely due to isolation by distance.