Natural Hybridization Between Quercus Dentata And Q. Mongolica-liaotungensis Revealed By Microsatellite Markers

As a quite common phenomenon in organismal groups, natural hybridization can play an important role in evolution. Analysis of natural hybridization provides insights into the process of speciation. While hybridization have long been thought to threaten species especially endangered species, recent work suggests that these processes are not necessarily a major impediment to effective species delimitation. However, through creating new genotype combinations, increasing genetic diversity and improving the ecological adaptability, it is a great potential resource in evolution.Because of The genus Quercus (the oaks), in which many species are known to hybridize, is a well-known example to evaluate hybridization and gene introgression. Two closely related oaks Q. mongolica and Q. liaotungensis are controversial in their species status. In order to elucidate whether Q. mongolica and Q. liaotungensis are genetically distinct from each other and is there any evidence of hybridization between the sympatric oak species, as well as investigate the genetic diversity, population structure and interspecies hybridization of sympatric oaks in Liantai Moutain were studied.9SSR markers of high polymorphism and well amplified were used in the analysis of total290individuals, of which162alleles were detected, and the mean number of alleles (Na) across all loci is18, mean effiective number of alleles (Ne) is7.5426, mean value of Shannon’s information index of diversity (7) is2.1904, mean value of expected heterozygosity (He) is0.8443, which is at high level of genetic diversity.Model-based clustering method was implemented in the program STRUCTURE, in which2clusters solution were given. Because of continuous on genetic compositon, Q. mongolica and Q. liaotungensis can not be considered as two discrete taxonomic units. Also, the results of clustering provides evidence of interspecies hybridization of5.86%(17out of290). Admixture coefficient (Q) was used to simulated F1hybrid (17.65%,3out of17) and backcrosses (82.35%,14out of17). Genetic differentiation coefficient (FST) is at low level. FST of Q. dentata (0.0254) is lower than Q. mongolica (0.0559), indicating that more genetic variation partitioned within populations. Gene flow (Nm) of Q. dentata (9.58) is higher than Q. mongolica (4.22).In summary, the microsatellite analysis revealed the continuous of Q. mongolica and Q. liaotungensis on genetic compositon, and a high genetic diversity and limited hybrid between Q. mongolica and Q. dentata. Our results can give implications for further study of genetic variation and succession tendency in oaks.