Genetic diversity and population structure analysis of Emmenopterys henryi Oliv., an endangered relic species endemic to China

A simple sequence repeat (SSR) marker was used to assess the genetic diversity and population structure of an endangered relic species Emmenopterys henryi Oliv., endemic to China. A total of 124 samples from six populations were analyzed using eight pairs of SSR primers. Total 114 alleles were detected with an average of 14.3 alleles per locus. The presence of null alleles can result in low genetic diversity parameters (H e and allelic richness) for all loci and mostly likely caused the deviation from Hardy–Weinberg equilibrium (HWE). The Polymorphism information content (PIC) values were higher which indicates that selection of SSR markers were suitable choice for assessing the genetic diversity in E. henryi . Our results revealed that the natural populations of E. henryi have a high degree of genetic diversity. Genetic diversity amongst the six E. henryi populations in decreasing order were: GJY > LS > DWS > WYS > HS > JGS. Further, genetic structure and the Neighbor-Joining (NJ) cluster analysis indicated that there were cross-mixing among the 124 samples. Four populations (i.e., HS, DWS, JGS and WYS) were clustered in one group, whereas LS and GJY population were clustered separately as two groups. A Principal Component Analysis (PCA) also showed a similar clustering trend. The results of F st (0.085) and AMOVA indicated that the genetic variation resided within the populations and existence of frequent gene exchanges among populations. Based on these results, populations with abundant genetic variation and rare alleles should be conserved in situ and ex situ. Furthermore, seeds from the different populations with high levels of genetic diversity could be collected and propagated in order to capture the maximum available genetic diversity. The present study on genetic diversity of E.henryi could be helpful in expanding the understanding on species survival and also for developing an effective long term conservation strategy.