Population genetics of Drosophila ananassae: inversion polymorphism and body size in Indian geographical populations

Abstract

Twelve Indian natural populations of Drosophila ananassae, a cosmopolitan and domestic species, were sampled and laboratory populations (mass cultures) were established from naturally impregnated females. These populations were maintained in the laboratory for some generations and were analysed chromosomally to know the frequency of different inversions. The chromosomal analysis revealed the presence of three cosmopolitan inversions. The data on the whole show that there are significant differences in the frequencies of different chromosome arrangements in these populations. Body size (wing length and thorax length) was measured in both sexes (50 females and 50 males), in all the 12 geographical populations of D. ananassae. There are statistically significant differences in wing length as well as in thorax length of both sexes among different geographical populations. Five geographical strains were crossed reciprocally and body size (wing length and thorax length) was measured in F 1 and F 2 progeny. The comparison of body size (both traits) between mid-parent, F 1 and F 2 shows that there is an increase in body size in F 1 and F 2 progeny as compared with parents. Thus, there is no break down of heterosis in F 2 , which suggests absence of coadaptation in geographical populations of D. ananassae. Scaling test statistical analysis showed additive, dominance and epistatic effects in certain crosses involving geographical strains of D. ananassae. Correlation between chromosome arrangement frequency and body size has also been tested and significant negative correlation has been found between 2L -ST chromosome arrangement and male thorax.

Inversion polymorphism in a Connecticut RiverAxarusspecies (Diptera: Chironomidae): biometric effects of a triple inversion heterozygote

“…This species shows a result very similar to ours where heterozygosity for a single inversion results in reduced body size (Norry et al 1995). Recently, Yadav and Singh (2003) demonstrated that in Drosophila ananassae, male thorax size was significantly reduced in correlation with heterozygosity for the 2L inversion and suggested that natural selection maintained this polymorphism. Biometric inversion effects have also been shown in grasshoppers.…”

Mapping Regions Within Cosmopolitan Inversion In(3R)Payne Associated With Natural Variation in Body Size in Drosophila melanogaster

“…This is especially the case in Drosophila, where inversions have been linked with traits such as body size (Fanara et al 1997;Orengo and Prevosti 2002;Yadav and Singh 2003), heat and cold tolerance (Anderson et al 2003), longevity (Rodriguez et al 1999), development time (Betrán et al 1998;Fernandez Iriarte and Hasson 2000), larva to adult viability (Fernandez Iriarte and Hasson 2000), female fecundity, and male mating success (Brockett et al 1996). Associations are presumably due to genes controlling variation for these traits that are located within or near the inverted region (Hoffmann et al 2004).…”

Chromosomal and environmental determinants of morphometric variation in natural populations of the malaria vector Anopheles funestus in Cameroon

“…In general, body size is affected only by some inversions, and negatively or positively associated with one of the homozygotes. Moreover, several studies have revealed a positive effect of heterosis (heterozygotes) in body size (Prevosti, 1967; Yadav and Singh, 2003). In our study, both homozygotes (standard and inverted) for the different inversions systems did not show significant wing size variation at local or country scale.…”