Year: 1996
Volume: 83
Issue: 11
Pages: 1379-1385
Topic: Genetics and Molecular Biology
Authors: Ann Marie Odasz and Outi Savolainen
Abstract: Isozyme variability was examined
in 13 geographically isolated populations of the endemic arctic hairy lousewort
(Pedicularis dasyantha) in the Svalbard Archipelago, 80° N latitude,
Norway. Of the 23 enzyme systems screened on five buffer systems 18 were interpretable.
Of the 31 reliable loci, only 6-phosphogluconate dehydrogenase (6-pgd),
was polymorphic However, no heterozygotes were detected Frequencies for allele
1 among the populations varied from 1.00 in the north to 0.00 in the south and
0.53 in the central "overlap" region. At the species level the mean number of
alleles per locus (A) was 1.03. Percentage of polymorphic loci (P)
was 3% Expected heterozygosity (H4) was 0.016 At the population level
the mean number of alleles per locus was 1.01, and 1.1% of the loci were polymorphic
H4 was 0.004. These values are low compared to endemic, widespread,
selfing, and outcrossed species Flower color morphs were distinct. They varied
within and among the 13 populations The frequency of color morphs coincided
with allele frequencies of 6-PGD: allele 1 was found in dark purple morphs,
and allele 2 was found in light morphs. This species shows more isozyme genetic
variability than the five other species reported in the genus but generally
less variation than other species with limited regional distributions. Low-level
genetic variation in this diploid species may be a result of colonization events
coupled with genetic drift, founder effects, and strong natural selection. Additional
factors include the self-compatible reproductive system and the long-lived perennial
habit.
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