Population Genetics of Drosophila ananassae: Variation in the Degree of Genetic Divergence in Populations Transferred to Laboratory Conditions

Pranveer Singh and Bashisth N. Singh (2008) Population genetics of Drosophila ananassae: variation in the degree of genetic divergence in populations transferred to laboratory conditions. Zoological Studies 47(6): 704-712. Forty-five laboratory populations of Drosophila ananassae initiated from females collected from different eco-geographical localities of India were maintained for several generations (a minimum of 10) and analyzed chromosomally to determine the frequencies of 3 cosmopolitan inversions. All laboratory populations under study showed variations with respect to the frequencies of the 3 cosmopolitan inversions, and remained polymorphic even after 10 generations, suggesting that heterotic buffering may be associated with the 3 cosmopolitan inversions in D. ananassae. Comparison of the same data with corresponding natural populations showed considerable changes in the frequencies of inversions and level of inversion heterozygosity between laboratory and natural populations. The degree of genetic divergence between initial and final populations of D. ananassae was quantified by calculating the genetic identity (1) and genetic distance (D) on the basis of differences in chromosome arrangement frequencies. Laboratory populations of D. ananassae showed variations in the degree of genetic divergence when transferred and maintained for several generations under laboratory conditions. Populations coming from similar environmental conditions and showing an initially high degree of genetic similarity had diverged to different degrees. Variations in the degree of genetic differentiation between different natural and laboratory populations are likely due to genetic drift. http://zoolstud.sinica.edu.tw/JournaIs/47.6/704.pdf