CHLOROPLAST MICROSATELLITES REVEAL POPULATION GENETIC DIVERSITY IN RED PINE, PINUS-RESINOSA AIT

Variation in paternally inherited chloroplast microsatellite (cpSSR) D NA was used to study population genetic structure in red pine (Pinus r esinosa Ait.), a species characterized by morphological uniformity, no allozyme variation, and limited RAPD variation. Using nine cpSSR loci , a total of 23 chloroplast haplotypes and 25 cpSSR alleles were found among 159 individuals surveyed in seven widely separated populations. The total genetic diversity, H-T, was 0.618, but haplotype differenti ation among populations was low (G(ST) = 0.121). All populations were distinguished from each other by their haplotype compositions, and onl y one haplotype was common among all populations. Based on average squ ared composite cpSSR length differences (stepwise haplotypes), within- population diversity was relatively high for only one population (D-SH (2) = 0.443). Frequency distributions of pairwise SSR differences amon g individuals within different populations, as well as branch length d ifferences in neighbour-joining dendrograms, indicated recovery from o ne or more population bottlenecks, and may be explained by metapopulat ion dynamics.