Elshibli, Sakina , Korpelainen, Helena .
Excess heterozygosity and scarce genetic differentiation in the populations of Phoenix dactylifera L.: human impact or ecological determinants.
Extensive research has been conducted on the characterization of thousands of date palm (Phoenix dactylifera L.) cultivars worldwide. However, the population genetics of date palms has never been studied. In this study, we collected 200 individuals from 19 populations from different geographic locations in Sudan. The collection sites grouped according to the type of dates (date palm fruits) that dominates in the area. Ten microsatellite markers were used to investigate the genetic diversity within and among populations, and the correlation between the genetic and geographic distances. The tested microsatellite markers showed a high level of polymorphism. A total of 261 alleles were detected at the ten loci. The overall mean value of fixation indices equalled -0.163, which shows the presence of excess heterozygosity. However, the chi-square tests conducted for every locus in each population indicated no significant deviation from the Hardy-Weinberg equilibrium. The AMOVA analysis exhibited that about 95% of the total genetic variation existed within populations, while significant differentiation within the type groups could be detected. Although significant isolation by distance (r2 = 0.552, p < 0.022) was detected by a Mantel test, it seems that the spatial effect has become complicated as a result from the exchange and introduction of different kinds of plant material by date palm growers and traders as well as seed dispersal. This complexity was clearly apparent in the weak clustering relationships among most of the tested populations.
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Research themes in Applied Biology Department, University of Helsinki;Molecular, ecological and population genetic projects
1 - University of Helsinki, Department of Applied Biology, P.O. Box 27, Helsinki, FI-00014, Finland
2 - University of Helsinki, Department of Applied Biology, P.O. Box 27, Helsinki, FIN-00014, Finland
Phoenix dactylifera L.
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, July 29th, 2008
Time: 9:30 AM