Genetic diversity and gene flow revealed by microsatellite DNA markers in some accessions of African Plum (Dacryodes edulis) in Cameroon

Abstract

Dacryodes edulis is a multipurpose tree integrated in the cropping system of Central African region still dominated by subsistence agriculture. Some populations grown are wild which can provide information on the domestication process, and could also represent a potential source of gene flow. Leaves samples for DNA extraction were collected from wild forms in Mbakwa supe region and from cultivated forms in Yaounde and Santchou region. Six microsatellites DNA markers were employed in genotyping to analyze population structure and gene flow. Amplification rate was high and genotyping revealed high level of genetic variation. The overall polymorphic level at the six loci was also high with average expected heterozygosity of 0.53; polymorphism of 0.46; mean allelic diversity of 0.5 and mean allele number of 8.33. There were no clear differences with only 1% variation among the three populations and 6% variation among individuals within populations. In contrast, the rate of heterozygosis was high in all the three populations. Both the number of migrant per generation (Nm=20) and the Wright’s Fstatistics (FST=0.012) suggest that there was substantial gene flow among the populations. These findings indicate that D. edulis possess a great potential of pollen dispersal and dominant crosspollination within populations. Most of the loci with private alleles (45%) were found in wild individuals which could be a source of pollen for crossing their cultivated relatives.

Key words: Dacryodes edulis, domestication, genetic diversity and structure.