Patterns of allozyme variation in relation to population size of the threatened plantMegaleranthis saniculifolia (Ranunculaceae) in Korea |
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Authors: | Chin-Sung Chang Do Yol Choi Hui Kim Tae Yoon Park Yong-Sik Kim |
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Institution: | (1) Department of Forest Sciences and the Arboretum, Seoul National University, 151-921 Seoul, Korea;(2) Department of Medicinal Plants Resources, Mokpo National University, 534-729 Muan-gun, Korea;(3) Graduate School of Education, Yonsei University, 120-749 Seoul, Korea;(4) Faculty of Natural Resources, Yeungnam University, 712-749 Gyongsan, Korea |
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Abstract: | Patterns of variation at 27 allozyme loci were investigated in the endangered endemic plantMegaleranthis saniculifolia. Levels of allozyme variation (A = 1.47,P = 40%,He = 0.088) were also compared with other endemic plant species. Genetic divergence between populations was very high (G
st
= 0.271 ), with moderate to high interpopulation differentiation, which probably arose through historical bottlenecks in
a landscape of habitat fragmentation and/or human influence. The percentage of polymorphic loci, heterozygosity, and mean
number of alleles per locus were positively related to population size, probably due to the stochastic loss of rare alleles
in the smaller populations. Individuals in the small and marginal populations (TB, KD, and CJ) showed higher proportions of
fixed loci. These ecologically marginal populations were typically more distant from the nearest neighboring population and
were more genetically distinct from one another. The genetic structure of the current population ofM. saniculifolia is probably the result of local extinctions of intervening populations. This, in turn, is due to the Pleistocene climatic
change and increased habitat destruction. A positive association appears to exist between genetic diversity and population
size. Although these small population sizes are more sensitive to stochastic events, securing a certain number of individuals
from the three larger populations (SB, JB, and TG) could be accomplished as part of a conservation strategy. In addition,
it is important to prioritize populations in different regions in order to limit population declines caused by large-scale
environmental catastrophes. |
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Keywords: | allozyme conservation endangered species endemic plant genetic structure Megaleranthis saniculifolia |
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