Population Dynamics and Genetic Homogeneity in Natural Populations of Drosophila melanogaster from Faisalabad, Pakistan

Drosophila melanogaster has been considered an important model species to explore the patterns of diversity in natural populations. The current study was conducted to study population dynamics and genetic variability, gene flow and rate of migration in Faisalabad. The samples were collected from 17 different collection sites and cultured in the laboratory. The data for temperature and humidity were also recorded. It was observed that a decrease in temperature and increase in relative humidity caused an increase in population number and vice versa. Ten RAPD primers were used for PCR. Four primers were further selected on the basis of their efficiency and reproducibility. The number of amplification products varied from 4 to 10 with an average of 7.0 bands per primer. Mostly, all the samples showed monomorphic bands except for few samples from the south of the city. The allele and genotype frequencies were measured at each RAPD loci. Average observed heterozygosity (Ht 0.1886) and the genetic variation (GST 0.129) showed that D. melanogaster natural populations had low level of genetic diversity. The dendrogram based on genetic similarities revealed three main groups of D. melanogaster populations. This pattern of genetic homogeneity due to low genetic variability in local populations was attributed to the gene flow with no genetic drift in D. melanogaster populations in Faisalabad.