Genetic variation and population structure in Korean endemic species: IV.Hemerocallis hakuunensis (Liliaceae)
1997
Kang, Soon Suk | Chung, Myong Gi
Hemerocallis hakuunensis, a Korean endemic species, maintains considerably higher levels of allozyme variation within populations (meanHe=0.253) and substantially lower levels of allozyme divergence among populations (meanG ST=0.077) than average values reported for other insect-pollinated, outcrossing herbs. Indirect estimates of the number of migrants per generation (Nm=3.00, calculated fromG ST;Nm=3.57, calculated from the frequency of nine alleles unique to single populations) indicate that gene flow has been extensive inH. hakuunensis. This is somewhat surprising when we consider the fact that no specialized seed dispersal mechanism is known, flowers are visited by bees, and the present-day populations of the species are discontinous and isolated. Results of a spatial autocorrelation analysis based on mean allele frequencies of 19 populations reveal that only 13% (95/720 cases) of Moran'sI values for the ten interpopulational distance classes are significantly different from the expected values and no distinct trend with respect to the distance classes is detected. Although it is unclear how the populations are genetically homogenous, it is highly probable thatH. hakuunensis might have a history of relatively large, continuous populations that had more chance for gene movement among adjacent populations after the last Ice Age. In addition, occasional hybridization withH. thunbergii in areas of sympatry in the central and southwestern Korean Peninsula may be one factor contributing the present-day high allozyme variation observed inH. hakuunensis.
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