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Vol. 47 No. 6, 2008
Population Genetics of Drosophila ananassae: Variation in the Degree of Genetic Divergence in Populations Transferred to Laboratory Conditions
Pranveer Singh and Bashisth N. Singh*
Genetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India
Pranveer Singh and Bashisth N. Singh (2008) 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 (I) 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.
Key words: Drosophila ananassae, Laboratory populations, Chromosome inversions, Genetic divergence, Genetic drift.
*Correspondence:
Tel: 91-542-2368145. Fax: 91-542-2368174.
E-mail:bnsingh@bhu.ac.in; bashisthsingh2004@rediffmail.com
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