Quantitative genetic analysis of natural variation in body size in Drosophila melanogaster

Abstract

Latitudinal, genetic variation in body size is a commonly observed phenomenon in many invertebrate species and is shaped by natural selection. In this study, we use a chromosome substitution and a quantitative trait locus (QTL) mapping approach to identify chromosomes and genomic regions associated with adaptive variation in body size in natural populations of Drosophila melanogaster from the extreme ends of clines in South America and Australia. Chromosome substitution revealed the largest effects on chromosome three in both continents, and minor effects on the X and second chromosome. Similarly, QTL analysis of the Australian cline identified QTL with largest effects on the third chromosome, with smaller effects on the second. How-

Genetic mapping of adaptive wing size variation in Drosophila simulans

“…Subsequent mapping using F10 progeny by Calboli et al (2003) confined the Chr 3 QTL interval to 3R, excluded much of 3L. Because of the higher resolution of the QTL analysis in Calboli et al we compare our results to this study rather than the Gockel et al (2002) study. Although potentially sharing a QTL on Chr 2R with D. melanogaster, the most significant QTL in D. simulans is located between markers L311 and L319 on Chr 3L (Figure 4).…”

“…The advent of whole-genome sequences and QTL mapping in both species offers an opportunity to compare their genetic bases. In the Gockel et al (2002) study, owing to the presence of In(3R)Payne in the parental lines and insufficient generations (F3), the reduction of meiotic recombination produced a broad QTL plateau, which spans B85% (cytological range ¼ 65E-99F) of Chr 3. Subsequent mapping using F10 progeny by Calboli et al (2003) confined the Chr 3 QTL interval to 3R, excluded much of 3L.…”

“…Linkage analyses by Gockel et al (2002) and Calboli et al (2003) on the Australian and the South American D. melanogaster populations have independently shown that wing area, often taken as a proxy for body size, is controlled by quantitative trait loci (QTL) on chromosome arms 3R and 2R. The congruency in QTL positions between the two studies points to a similar genetic mechanism in different continental populations.…”

“…QTL mapping of wing size in D. melanogaster has suggested overlapping genetic mechanisms in Australia and South America (Gockel et al, 2002;Calboli et al, 2003). However, whether the same genetic basis is also conserved in another species is yet to be established.…”

“…The current study follows an approach similar to Gockel et al (2002) to investigate the genetic basis of the adaptive wing size variation in D. simulans using inbred lines originating from cline-end populations (Queensland and Tasmania). Mendelian genetic analysis indicated the basic genetic architecture-that large wing size is an autosomal dominant trait, with minor contribution from the sex chromosome, and unequal additive effect from chromosomes 2 and 3.…”