GENETIC DIVERSITY IN Pinus hartwegii IN THE TRANS-MEXICAN VOLCANIC BELT AND EASTERN SIERRA MADRE IN MEXICO

Abstract

Population of Pinus hartwegii are located at approximate altitudes between 3000 and 4200 masl in the mountains of Mexico and Central America, where Winter temperatures are low and environmental changes are common due to human activity. Genetic diversity is important in the adaptation of species to environmental changes. DNA molecular markers are efficient techniques for knowing the magnitude of genetic diversity in a species. Thus, the objective of this study was to estimate the genetic diversity in Pinus hartwegii in population and altitudinal levels in the Trans-Mexican Volcanic Belt and the Eastern Sierra Madre using microsatellites. Deoxyribonucleic acid was extracted from foliage collected from 84 trees in seven populations from the Trans-Mexican Volcanic Belt and Eastern Sierra Madre of Mexico. Trees were grouped into three altitudinal levels (<3700, 370-3900 and >3900 masl). Ten nuclear microsatellites were used to estimate the percentage of polymorphic loci, mean number of alleles per locus, observed and expected heterozygosity. The mean percentage of polymorphic loci was 77 %. The average number of alleles per locus varied from 3.8 to 5.0 between populations and from 5.2 to 7.8 between altitudinal levels. The observed heterozygosity ranged between 0.250 and 0.400 between populations and from 0.267 to 0.354 between altitudinal levels. The expected heterozygosity was from 0.369 to 0.462 among populations and from 0.448 to 0.482 among altitudinal strata. Genetic diversity in Pinus hartwegii is sufficient for an evolutionary potential that allows a greater probability of adaptation of this species to environmental changes in the populations studied in the Trans-Mexican Volcanic Belt and Eastern Sierra Madre of Mexico.