Unraveling the genetic diversity and structure of population through analysis of microsatellite markers.

BACKGROUND

Koidz. is an ecologically and economically important tree species widely distributed in Northern China. However, the effective assessment, utilization, and protection of resources remain unexplored.

METHODS

In total, 120 samples obtained from 12 populations of Northern China were investigated for genetic diversity and structure using 19 simple sequence repeat (SSR) primer pairs.

RESULTS

The total number of alleles detected was 293, the average number of effective allele (e) was 6.084, the genetic differentiation coefficient (st) was 0.033, and the mean observed heterozygosity (o) and expected heterozygosity (e) were 0.690 and 0.801, respectively. Moreover, analysis of molecular variance (AMOVA) showed a 5.5% genetic variation among 12 populations, indicating that a high level of genetic diversity and a low degree of genetic differentiation among populations. STRUCTURE and cluster analysis divided the 12 populations into the following three subpopulations: Bashang Plateau subpopulation (SH), Liaodong Peninsula subpopulation (NC), and Loess Plateau subpopulation (other 10 populations). The cluster analysis based on 19 climatic factors was consistent with the genetic structure. A positive correlation was found between genetic distance and geographical distance ( = 0.638,  = 0.028) by the Mantel test, and two boundaries were found among the 12 populations by the Barrier analysis, indicating that populations existed isolated by geographical distance and physical barrier.

CONCLUSION

This study suggests that geographical isolation, physical barrier, climatic types, and natural hybridization promote the formation of genetic structures, which can contribute to future protection and genetic improvement of