Genomes and Genes
QUANTITATIVE TRAIT LOCI RELATED TO DROSOPHILA SPECIATION
Principal Investigator: Sergey Nuzhdin
Abstract: There has been renewed interest in the genetics of speciation, yielding many theoretical and empirical results. However, most mapping studies of polygenes responsible for morphological/behavioral differences between species have had very crude resolution, only down to the level of very large chromosome segments. The actual genes responsible for these evolutionary changes are unknown. A trait involved in Drosophila mating choice, male sex comb, is an ideal model system for further progress. Sexual selection has generated differences between sibling species that exhibit only partial postzygotic isolation, enabling genetic analysis. Moreover, the biochemical and developmental pathways responsible for sex comb formation are among the best understood, with a large choice of candidate genes. Our long-term goal is to dissect the molecular genetic basis of interspecific differences using sex comb evolution as a model. We will capitalize on the region 73A-84BD, known to contribute half of the tooth number difference between D. simulans and D. mauritiana. This region also affects bristle number on the anal plate, clasper, and the 5th sternite. First, we will increase the mapping precision ten fold to determine whether these effects are due to on e major gene with pleiotropic effects, several genes with trait-specific effects, or several genes with smaller, additive or epistatic, effects. Second, we will identify these quantitative trait genes (QTG) using P element hopping and mapping based on site-specific P element- induced male recombination. Third, we will compare the alleles contributing to intraspecific variation with those causing interspecific differences. We will sample 100 natural D. simulans QTG alleles and substitute them into the otherwise identical genetic background within 100-200kbp chromosome intervals. This will determine the distribution of effects of natural QTG alleles. We will identify molecular polymorphisms segregating between QTG alleles that modify sex comb, and find their frequencies in both D. simulans and D. mauritiana. Finally, we will test whether these QTG alleles contribute to pre- and postmating reproductive isolation between species. This comprehensive assessment of the genetics of several traits will further our understanding of the genetics of speciation.
Funding Period: 2000-07-01 - 2006-06-30
more information: NIH RePORT
- The strength of transcription-factor binding modulates co-variation in transcriptional networksSergey V Nuzhdin
University of Southern California, Program in Molecular and Computational Biology, Los Angeles, CA 90089, USA
Trends Genet 26:51-3. 2010..Here we integrate two publicly available data sets in Drosophila melanogaster, as well as conduct novel analyses, to address these questions...
- Naturally segregating quantitative trait loci affecting wing shape of Drosophila melanogasterJason G Mezey
Center for Population Biology and Section of Evolution and Ecology, University of California, Davis, 95616, USA
Genetics 169:2101-13. 2005..Naturally segregating variation can therefore act through known signaling pathways to produce variation in vein position...
- Survival analysis of life span quantitative trait loci in Drosophila melanogasterSergey V Nuzhdin
Section of Evolution and Ecology, University of California, Davis, 95616, USA
Genetics 170:719-31. 2005..Our findings are broadly consistent with a mix of transient deleterious mutations and a few polymorphisms maintained by balancing selection, which together contribute to standing genetic variation in life span...
- Genomic islands of speciation in Anopheles gambiaeThomas L Turner
Center for Population Biology, University of California, Davis, California, USA
PLoS Biol 3:e285. 2005..Concentrating future mapping experiments on these regions should reveal the genes responsible for reproductive isolation between forms...
- The dimensionality of genetic variation for wing shape in Drosophila melanogasterJason G Mezey
Department of Biological Science, Florida State University, Tallahassee, Florida 32306 1100, USA
Evolution 59:1027-38. 2005..We discuss the importance of this result for resolving the relative roles of selection and drift processes versus constraints in the evolution of wing shape in Drosophila...
- Genetic variation for expression of the sex determination pathway genes in Drosophila melanogasterAaron M Tarone
Evolution and Ecology, University of California at Davis, CA 95616, USA
Genet Res 86:31-40. 2005....
- Locus- and population-specific selection and differentiation between incipient species of Anopheles gambiaeThomas L Turner
Center for Population Biology, University of California, Davis, USA
Mol Biol Evol 24:2132-8. 2007..There is reduced variation in the M form in Cameroon at this location and increased divergence to the outgroup Anopheles arabiensis, supporting an association of adaptation with reproductive isolation...
- Quantitative trait loci affecting phenotypic plasticity and the allometric relationship of ovariole number and thorax length in Drosophila melanogasterAlan O Bergland
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA
Genetics 180:567-82. 2008..The results are discussed in the context of multivariate trait evolution...