Assessment of the genetic diversity and population structure of Maire yew (Taxus chinensis var. mairei) for conservation purposes

Maire yew (Taxus chinensis var. mairei (Lemee et Levl) Cheng et L. K. Fu) is an endangered coniferous species in China. We examined the genetic pattern of Maire yew populations and explored any genetic variation among three groups (Core, Edge, and Disturb) based on hemeroby. Twenty-five populations (533 individuals) were analyzed using nuclear and mitochondrial simple sequence repeat (nSSR and mtSSR, respectively) markers and chloroplast DNA (cpDNA) sequences. nSSR marker analysis indicated a moderate level of genetic diversity (H-e = 0.467), a high level of biparental inbreeding within populations (F-IS = 0.314; P < 0.01), and a strong genetic differentiation among populations (F-ST = 0.161). Restricted gene flow due to mating characteristics and long-term isolation is the main factor affecting the natural genetic pattern. Our study suggested that human influence had a strong effect on the genetic diversity and differentiation. The results based on nSSR analysis showed that the human-influenced populations (Distub group) had the highest genetic diversity (H-e = 0.500, A(r) = 3.790) and the lowest genetic differentiation (F-ST = 0.062) among populations compared with that of the natural populations (Core group, H-e = 0.463, A(r) = 3.148, F-ST = 0.221). However, the analysis of cpDNA sequences showed an opposite trend on genetic diversity. The information presented here can supply the basis for genetic guidelines for appropriate conservation programs.