Genetic variation in Fagus multinervis Nakai (Fagaceae), a beech species endemic to Ullung Island, South Korea

Abstract

AbstractThe genetic variation of Fagus multinervis Nakai (Fagaceae), which is endemic to Ullung Island, South Korea, was investigated using allozyme polymorphisms as a genetic marker. A total of 1074 individuals collected from five populations were analyzed and the levels of genetic diversity were compared to those of Fagus japonica and Fagus crenata distributed in Japan. The percentages of polymorphic loci and the number of alleles per locus of F. multinervis were similar to those of the other beech species and to other long‐lived woody species. However, the heterozygosities in both direct counts and Hardy–Weinberg’s expected values were considerably higher in F. multinervis and F. japonica, which belong to the same subgenus Engleriana, than the other beech species that belong to another subgenus Fagus. Based on the five allozyme loci, approximately 1.5–3.0‐fold higher mean values of heterozygosities were found in the multistemmed beeches F. multinervis and F. japonica. The reason why such higher rates of heterozygosities were found in these species is also discussed. The proportions of expected effective population sizes (i.e. Nem/Nec, Nej/Nec and Nem/Nej) between the species were calculated, and these were Nem/Nec = 6.57, Nej/Nec = 6.73 and Nem/Nej = 0.98, respectively, in which Nem, Nej and Nec are the effective population sizes of F. multinervis, F. japonica and F. crenata, respectively.