DNA-based differentiation among four Lithuanian Scots pine populations

Abstract

Most of the former studies on genetic differences between Scots pine populations in Lithuania were based phenotype. The interest is to investigate population differentiation within Lithuania based on neutral highly variable DNA markers such as microsatellites. Objective of the study was to assess genetic differences between 4 Lithuanian populations representing 4 different adaptive environments based on nuclear (nSSR), chloroplast (cpSSR) microsatellites and mitochondrial DNA NAD7.1 locus. The main aim was to pre-screen for the efficiency of a larger number of loci to reveal population differences within Lithuania to be further used on a large material. 7 nSSR loci, 8 cpSSR loci and 1 mtDNA locus were studied in each of the following populations: Labanoras (eastern Lithuania), Juodkrantė (western), Višakio Rūda (central) and Mažeikiai (northern). The mtDNA results revealed no marked differences in the frequency of the northern type of mtDNA Nad7.1 295 bp allele with the tendency of slightly higher frequency in the eastern populations. Based on the cpSSR loci, the population differentiation was significant and the among-population variance component was markedly greater than that for the nSSRs. The multilocus clustering based on the cpSSR genetic distance revealed greater similarity between the western Lithuanian populations and genetic separation of central Lithuanian population. Whereas according to the multilocus nSSR clustering, the sea-side spit of Neringa was distinguishing from the rest and the two northern-most populations from Labanoras and Mažeikiai shared a single cluster. In conclusion, our study showed a significant population differentiation especially at the cpSSR loci within Lithuania and provided the background for a more detail investigation based on the loci studied. Merging of present-day regions of provenance are discussed.