Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall.) Regel at the Eastern Baikal Lake shore

Authors

  • E.A. Petrova Institute for Monitoring of Climatic and Ecological Systems, Siberian Branch of Russian Academy of Science, Tomsk, Russia
  • S.N. Goroshkevich Institute for Monitoring of Climatic and Ecological Systems, Siberian Branch of Russian Academy of Science, Tomsk, Russia
  • Y.S. Belokon Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
  • D.V. Politov Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia

DOI:

https://doi.org/10.15287/afr.2008.142

Keywords:

natural hybridization, Pinus sibirica, Pinus pumila, allozymes, mating system, genetic structure, Baikal Lake

Abstract

Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall.) Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin) by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca, Pgi-1, Pgd-2, Pgd-3, Pgm-1 and Pgm-2. All hybrids were heterozygous for the diagnostic Skdh-2 locus. Classification into hybrids and parental species using PCA analysis of multilocus allozyme genotypes had good correspondence with diagnoses made by morphological and anatomical analyses. Approximately 27% of embryos in P. pumila seeds had P. sibirica paternal contribution, and 8% of haplotypes in effective pollen pool combined alleles typical for P. pumila and P. sibirica, and therefore were classified as pollinated by the hybrids. About 83% of embryos in seeds from the hybrids most likely originated from fertilization by P. sibirica pollen, 14% from P. pumila and 3% from hybrid trees. This result favours the view that hybrids make both male and female contributions to the reproductive output of the population and confirm the presence of backcrosses and F2 hybrids.

Downloads

Published

2007-11-13

Issue

Section

Research article