Low genetic variation in Amentotaxus formosana Li revealed by isozyme analysis and random amplified polymorphic DNA markers
Journal
Heredity
Journal Volume
77
Journal Issue
4
Pages
388-395
Date Issued
1996
Author(s)
Abstract
The objective of this research was to use random amplified polymorphic DNA (RAPD) and isozyme analysis to investigate genetic variation in narrowly distributed populations of Amentotaxus formosana Li. A total of 20 loci from 10 enzyme systems were analysed in 50 individual trees from each of the two natural populations. No isozyme variation was observed in the Tsatsayalai population. Phosphoglucose isomerase (Pgi-l) was the only polymorphic enzyme in the Tawu population, giving 5 per cent polymorphic loci with 0.008 expected heterozygosity. No genetic distance was found between these two populations using isozymes. Amentotaxus formosana demonstrated a high proportion of monomorphic RAPD fragments, about 79 per cent, for 20 arbitrary oligonucleotide primers. High similarity (0.994) was found between the Tawu and Tsatsayalai populations. RAPD markers provided further confirmation of the low levels of genetic variation in A. formosana detected by isozyme analysis. The value of isozyme analysis was emphasized by the finding of the rare allele, Pgi-la, which was present only in the Tawu population. Based on the analysis of 110 individuals, representing 16 per cent of a native population, it was found that the younger tree category had a higher frequency of Pgi-la (0.125) than the older tree category (0.053), resulting in an expected heterozygosity of 0.250 and 0.105, respectively. It was inferred that the appearance of the Pgi-la allele could be the result of a mutation in the Tawu population and that selection is acting directly upon trees carrying this allele.
SDGs
Type
journal article