Chromosomal morphism in Drosophila nasuta Lamb II. Coexistence of heteroselection and flexibility in the polymorphic system of South Indian populations
✍ Scribed by H. A. Ranganath; N. B. Krishnamurthy
- Publisher
- Springer Netherlands
- Year
- 1978
- Tongue
- English
- Weight
- 518 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0016-6707
No coin nor oath required. For personal study only.
✦ Synopsis
Chromosomal polymorphism in South Indian populations of D. nasuta Lamb has been investigated. An analysis has been made of geographical, altitudinal and seasonal variation in chromosomal polymorphism in D. nasuta. The mean number of inversions shows geographical and altitudinal clines and there are also significant differences in the population structure in different months. Further, heterokaryotypes usually represent more than fifty per cent of individuals in all samples studied. Thus, D. nasuta represents an example of 'flexible polymorphism' with heteroselection. The pattern 'of chromosomal polymorphism is discussed.
proved that the Seychelles Island strain of D. nasuta and the South Indian strains of D. nasuta are one and the same species. The results of these hybridization experiments will be reported elsewhere. D. nmuta possesses a high level of chromosomal rearrangements (Nirmala & Krishnamurthy, 1974). The aim of the present study is to understand the type of selection and the nature of chromosomal polymorphism in South Indian populations of D. nasuta. Geographical, altitudinal and monthly variations in the frequencies of inversions have been studied and the results are presented below.