Are the same genes responsible for intra- and interspecific variability for sex comb tooth number in Drosophila?

Abstract A quantitative trait locus (QTL) genetic analysis of morphological and reproductive traits distinguishing the sibling species Drosophila simulans and D. sechellia was carried out in a backcross design, using 38 markers with an average spacing of 8.4 cM. The direction of QTL effects for the size of the posterior lobe was consistent across the identified QTL, indicating directional selection for this trait. Directional selection also appears to have acted on testis length, indicating that sexual selection may have influenced many reproductive traits, although other forms of directional selection cannot be ruled out. Sex comb tooth number exhibited high levels of variation both within and among isofemale lines and showed no evidence for directional selection and, therefore, may not have been involved in the early speciation process. A database search for genes associated with significant QTL revealed a set of candidate loci for posterior lobe shape and size, sex comb tooth number, testis length, tibia length, and hybrid male fertility. In particular, decapentaplegic (dpp), a gene known to influence the genital arch, was found to be associated with the largest LOD peak for posterior lobe shape and size.

Download Full-text

Genetic architecture of variation in sex-comb tooth number in Drosophila simulans

Genetics Research ◽

10.1017/s0016672306008111 ◽

2006 ◽

Vol 87 (2) ◽

pp. 93-107 ◽

Cited By ~ 11

Author(s):

HARUKI TATSUTA ◽

TOSHIYUKI TAKANO-SHIMIZU

Keyword(s):

Interspecific Variation ◽

Drosophila Simulans ◽

Epistatic Interactions ◽

The Third ◽

Sex Comb ◽

Tooth Number ◽

Comb Tooth ◽

Trait Locus ◽

The Relationship ◽

Mapping Populations

The sex comb on the forelegs of Drosophila males is a secondary sexual trait, and the number of teeth on these combs varies greatly within and between species. To understand the relationship between the intra- and interspecific variation, we performed quantitative trait locus (QTL) analyses of the intraspecific variation in sex-comb tooth number. We used five mapping populations derived from two inbred Drosophila simulans strains that were divergent in the number of sex-comb teeth. Although no QTLs were detected on the X chromosome, we identified four QTLs on the second chromosome and three QTLs on the third chromosome. While identification and estimated effects of the second-chromosome QTLs depend on genetic backgrounds, significant and consistent effects of the two third-chromosome QTLs were found in two genetic backgrounds. There were significant epistatic interactions between a second-chromosome QTL and a third-chromosome QTL, as well as between two second-chromosome QTLs. The third-chromosome QTLs are concordant with the locations of the QTLs responsible for the previously observed differences in sex-comb tooth number between D. simulans and D. mauritiana.

Download Full-text

The large X-effect on secondary sexual characters and the genetics of variation in sex comb tooth number inDrosophila subobscura

Ecology and Evolution ◽

10.1002/ece3.2634 ◽

2016 ◽

Vol 7 (2) ◽

pp. 533-540 ◽

Cited By ~ 6

Author(s):

Briana E. Mittleman ◽

Brenda Manzano-Winkler ◽

Julianne B. Hall ◽

Katharine L. Korunes ◽

Mohamed A. F. Noor

Keyword(s):

Secondary Sexual Characters ◽

Sex Comb ◽

Tooth Number ◽

Comb Tooth ◽

Secondary Sexual

Download Full-text

Studies on fluctuating asymmetry (FA) for certain morphological traits in four species of the Drosophila bipectinata complex

Genetika ◽

10.2298/gensr1502535b ◽

2015 ◽

Vol 47 (2) ◽

pp. 535-548 ◽

Cited By ~ 3

Author(s):

Parul Banerjee ◽

Narayan Singh

Keyword(s):

Fluctuating Asymmetry ◽

Bilateral Symmetry ◽

Distinct Species ◽

Evolutionary Divergence ◽

Consistent Difference ◽

Drosophila Bipectinata ◽

Sex Comb ◽

Tooth Number ◽

Pattern Of Variation ◽

The Right

Fluctuating asymmetry (FA) is defined as subtle deviations from perfect bilateral symmetry, evident in differences between the right and the left sides of any given trait. It is a pattern of variation between sides and measures developmental instability. Differences in the level of FA may be used for comparing developmental precision among closely related species and thus may give an idea whether developmental stability was affected during the divergence and separation of populations into distinct species. Keeping this in view, FA was studied in four species of the Drosophila bipectinata complex i.e. D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae. In females of all the four species, FA values did not vary significantly for any of the traits considered. However, in case of males, they varied significantly for Wing length (WL) and sex comb tooth number (SCTN). Also, while in females Composite fluctuating asymmetry (CFA) did not exhibit significant variation, in males it was found to vary significantly across the four species. However, Bonferroni t-tests did not reveal any consistent difference in FA levels between any two species. The magnitude of FA was found to differ significantly among traits and CFA values were found to be higher for males than females in all the four species. Therefore, it may be concluded that the level of FA shows trait specific variations and males are more prone to developmental perturbations. However, the FA levels are more or less similar in all the four species of this complex. Thus, developmental precision remains nearly same in all the four species of this complex irrespective of the degree of evolutionary divergence reached.

Download Full-text

Genetic studies of three sibling species of Drosophila with relationship to theories of speciation

Genetics Research ◽

10.1017/s0016672300022643 ◽

1985 ◽

Vol 46 (2) ◽

pp. 169-192 ◽

Cited By ~ 59

Author(s):

Jerry A. Coyne

Keyword(s):

Reproductive Isolation ◽

Continuous Process ◽

Isolated Populations ◽

Genetic Studies ◽

Related Pair ◽

Gonadal Atrophy ◽

Sex Comb ◽

Tooth Number ◽

Founder Event ◽

Behavioural Tests

SUMMARYDrosophila melanogaster, D. simulans and D. mauritiana are closely related species, the first two cosmopolitan and the last restricted to the oceanic island of Mauritius. D. simulans and D. mauritiana are the most closely related pair, with the latter species probably resulting from a founder event. The relatedness of the three species and their ability to hybridize allow tests of recent theories of speciation. Genetic analysis of two characters differing between D. simulans and D. mauritiana (sex comb tooth number and testis colour) show that the differences are due to at least five and three loci respectively. Behavioural tests further demonstrate that sex combs are probably used by males at a crucial step in mating, and that the differences between the two species may be related to differences in their mating ability. These genetic studies and previous work indicate that differences among these species are polygenic and not (as proposed by recent theories) attributable to only one or two loci of large effect. Further studies of interspecific hybrids show that genetic divergence leading to developmental anomalies is more advanced in the older species pair D. simulans/D. melanogaeter than in the younger pair D. simulans/D. mauritiana. This supports the neo-Darwinian contention that reproductive isolation is one step in a continuous process of genetic change among isolated populations, and does not support current theories that such change occurs only during the evolution of reproductive isolation. Finally, investigations of the degree of gonadal atrophy and its sensitivity to temperature in D. simulans/D. mauritiana hybrids fail to support recent speculations that phenomena similar to hybrid dysgenesis (which causes such atrophy in D. melanogaster) play a role in speciation.

Download Full-text