Genetic diversity and structure of morphologically characterized populations Pinus ayacahuite and Pinus strobiformis through the analysis of neutral nuclear markers

Abstract

Diversity and genetic structure of Pinus ayacahuite and Pinus strobiformis was assessed by random amplified polymorphic DNA (RAPD) variation. Eleven populations distributed along a latitudinal gradient in Mexico were morphologically identified as P. strobiformis, P. ayacahuite var. veitchii or P. ayacahuite var. ayacahuite. A total of 69 primers were screened, and 10, that amplified 51 intense and reproducible fragments, were chosen for the genetic analysis. None of the 51 fragments were unique to a population. Genotypic diversity (Hj) ranged from 0.222 to 0.287 among populations. The total gene diversity (HT) of P. ayacahuite and P. strobiformis was 0.276 and 0.318, respectively. FST values showed most genetic variation to be within populations. Differentiation among wingless populations of P. strobiformis was almost double (FST=0.179) than that of winged seed populations of P. ayacahuite (FST=0.080). The AMOVA analysis confirmed these results. The analysis with STRUCTURE showed three genetic groups and the population of Cerro el Potosi as clearly differentiated. This population and seed dispersal mechanisms other than dissemination by Clark’s nutcracker might explain the high differentiation found in P. strobiformis. Management of P. ayacahuite and P. strobiformis in Mexico should be aimed to maintain morphologically and genetically well-differentiated populations.