Chromosomal polymorphism in Indian populations of Drosophila bipectinata Duda

2015

J Genet

Biodiversity is the sum total of all living things on the earth with particular reference to the profound variety in structure,function and genetic constitution. It includes both number and frequency of species or genes in a given assemblage and the variety of resulting ecosystems in a region. It is usually considered at three different levels: genetic, species and ecological diversities. Genus Drosophila belongs to the family Drosophilidae (class Insecta, order Diptera), characterized by rich species diversity at global level and also in India, which is a megadiverse country. At global level, more than 1500 species have been described and several thousands estimated. Hawaiian Islands are particularly rich in species diversity with more than 500 species which provides a unique opportunity to study evolution in genus Drosophila. About 150 species of Drosophila have been reported from India. Certain species of Drosophila found in India have been investigated for genetic diversity within the species. In this regard, Drosophila ananassae is noteworthy. It is a cosmopolitan and domestic species with common occurrence in India and is endowed with many genetic peculiarities. Population genetics and evolutionary studies in this species have revealed as to how genetic diversity within a species play an important role in adaptation of populations to varying environments. In addition, the work carried on D. melanogaster, D. nasuta, D. bipectinata and certain other species in India has shown that these species vary in degree and pattern of genetic diversity, and have evolved different mechanisms for adjusting to their environments. The ecological adaptations to various kinds of stress studied in certain species of Drosophila inhabiting the Indian subcontinent are also discussed.

Section: Intraspecific Genetic Variabilitymentioning

confidence: 98%

Species and genetic diversity in the genus Drosophila inhabiting the Indian subcontinent

2015

J Genet

“…1. These inversions were detected earlier from different laboratory stocks (Bock 1971;Gupta and Panigrahy 1990;Das and Singh 1992;Banerjee and Singh 1994). All these three inversions are widely distributed with low frequency in Indian natural populations (Banerjee and Singh 1996).…”

Section: Resultsmentioning

confidence: 71%

“…It is known to have a wide geographical distribution ranging from India through southeast Asia and New Guinea to Fiji and Samoa in the Pacific (Bock and Wheeler 1972). Chromosomal polymorphism has been studied in D. bipectinatu and 12 paracentric inversions are known in this species (Bock 1971;Gupta and Panigrahy 1990). Certain inversions often persists in laboratory stocks of D. bipectinuta (Singh and Das 1991;Das and Singh 1992;Banerjee and Singh 1994;Singh and Banerjee 1995).…”

Section: Introductionmentioning

confidence: 99%

Increase in the degree of inversion polymorphism in Drosophila bipectinata populations transfereed to laboratory conditions

Journal of Zoological Systematics and Evolutionary Research

Banerjee

2009

Thirteen laboratory populations (six mass cultures and seven isofemale lines) of Drosophila bipectinata were established from flies collected from six different geographic localities (four in the north and two in the south) in India. These mass cultures and isofemale lines were maintained in food bottles in the laboratory for varying number of generations by transferring about 50 flies (females and males in equal number) in each generation. After several generations, all the laboratory populations were analysed chromosomally to determine the frequency of different inversions. The results indicate that all the laboratory populations remained chromosomally polymorphic due to the persistence of inversions which were originally present in the populations. The quantitative data on the frequency of inverted gene orders and the level of inversion heterozygosity in laboratory populations are compared with those in corresponding natural populations. This comparison clearly shows that there is a considerable increase in the frequency of inverted gene orders and the level of inversion heterozygosity in laboratory populations when compared with corresponding natural populations. This is most likely to be due to selective advantage of inversion heterozygotes under stringent competition in laboratory populations. Thus heterotic buffering is associated with chromosome inversions of Drosopliilu bipectinata.

“…We followed the nomenclature of Jha and Rahman (1972), Gupta and Panigrahy (1990) and Tomimura et al (2005) which is slightly different from Bock's (1971b). His 3L has been designated 3R and 3R has been designated 3L by us as 3L and 3R of D. malerkotliana (Jha and Rahman 1972) closely resembles 3L and 3R of D. ananassae, named by Ray-Chaudhuri and Jha (1965).…”

Section: Inversions Found In the Laboratory Stocks Of The Complexmentioning

confidence: 99%

The Drosophila bipectinata species complex: phylogenetic relationship among different members based on chromosomal variations

Banerjee

2017

J Genet

Making interspecific hybridizations, where possible remains an unparalleled option for studying the intricacies of speciation. In the Drosophila bipectinata species complex comprising of four species, namely D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae, interspecific hybrids can be obtained in the laboratory, thus bequeathing an ideal opportunity for studying speciation and phylogeny. With the view of investigating the degree of divergence between each species pair, we planned to study the polytene chromosomes of the F hybrids, as it would mirror the level of compatibility between the genomes of the parental species. Two sets of crosses were made, one involving homozygous strains of all four species from India and the other including homozygous strains from different places across the globe. Polytene chromosomes of F larvae from both sets of crosses had similar configurations. In F larvae from crosses involving D. bipectinata, D. parabipectinata and D. malerkotliana, complex configurations (depicting overlapping inversions) could be detected in different arms. However, they were fairly synapsed, indicating that the differences are only at the level of gene arrangements. The polytene chromosomes of larvae obtained by crossing D. pseudoananassae with the other three species were very thin with gross asynapsis in all the arms, demonstrating that the genome of D. pseudoananassae is widely diverged from rest of the species. The overlapping inversions (reflected in complex configuration), are inferred in the light of earlier chromosomal studies performed in this complex.