Genetic diversity and population structure of Caragana microphylla Lam. based on analysis of inter-simple sequence repeat markers

Abstract

Caragana microphylla Lam. is a long-lived shrub species in the semi-arid, arid and desert regions. To determine the genetic diversity and population structure of C. microphylla Lam., 17 wild populations from the central and eastern part of Inner Mongolia were analyzed by inter-simple sequence repeat. 18 primers  produced 296 bands across a total of 510 individuals. A high percentage of polymorphic loci was observed at species level (PPB = 81.4%). Based on analysis of molecular variance, 74.99% of the genetic variation of C. microphylla Lam. was found within population, 7% difference between regions and 15.2% among collection  sites within regions. Cluster analyses showed that 17 populations are most arranged in the same cluster by  geographic location. An indirect estimate of the G_ST-derived N_m value (N_m = 1.8921) indicate that gene flow is high among 17 populations. No significant correlation (r2 = 0.13) between genetic and geographic distance was detected. Results of this study suggest that C. microphylla Lam. has a high genetic variability and potential as a source of variation for breeding programs.

Key words: Inter-simple sequence repeat (ISSR), Caragana microphylla Lam., genetic structure.