QUANTITATIVE TRAIT LOCI RELATED TO DROSOPHILA SPECIATION

Summary

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

Top Publications

  1. pmc The strength of transcription-factor binding modulates co-variation in transcriptional networks
    Sergey V Nuzhdin
    University of Southern California, Program in Molecular and Computational Biology, Los Angeles, CA 90089, USA
    Trends Genet 26:51-3. 2010
  2. pmc Naturally segregating quantitative trait loci affecting wing shape of Drosophila melanogaster
    Jason G Mezey
    Center for Population Biology and Section of Evolution and Ecology, University of California, Davis, 95616, USA
    Genetics 169:2101-13. 2005
  3. pmc Survival analysis of life span quantitative trait loci in Drosophila melanogaster
    Sergey V Nuzhdin
    Section of Evolution and Ecology, University of California, Davis, 95616, USA
    Genetics 170:719-31. 2005
  4. pmc Genomic islands of speciation in Anopheles gambiae
    Thomas L Turner
    Center for Population Biology, University of California, Davis, California, USA
    PLoS Biol 3:e285. 2005
  5. ncbi The dimensionality of genetic variation for wing shape in Drosophila melanogaster
    Jason G Mezey
    Department of Biological Science, Florida State University, Tallahassee, Florida 32306 1100, USA
    Evolution 59:1027-38. 2005
  6. ncbi Genetic variation for expression of the sex determination pathway genes in Drosophila melanogaster
    Aaron M Tarone
    Evolution and Ecology, University of California at Davis, CA 95616, USA
    Genet Res 86:31-40. 2005
  7. ncbi Locus- and population-specific selection and differentiation between incipient species of Anopheles gambiae
    Thomas L Turner
    Center for Population Biology, University of California, Davis, USA
    Mol Biol Evol 24:2132-8. 2007
  8. pmc Quantitative trait loci affecting phenotypic plasticity and the allometric relationship of ovariole number and thorax length in Drosophila melanogaster
    Alan O Bergland
    Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA
    Genetics 180:567-82. 2008

Scientific Experts

Detail Information

Publications8

  1. pmc The strength of transcription-factor binding modulates co-variation in transcriptional networks
    Sergey 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...
  2. pmc Naturally segregating quantitative trait loci affecting wing shape of Drosophila melanogaster
    Jason 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...
  3. pmc Survival analysis of life span quantitative trait loci in Drosophila melanogaster
    Sergey 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...
  4. pmc Genomic islands of speciation in Anopheles gambiae
    Thomas 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...
  5. ncbi The dimensionality of genetic variation for wing shape in Drosophila melanogaster
    Jason 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...
  6. ncbi Genetic variation for expression of the sex determination pathway genes in Drosophila melanogaster
    Aaron M Tarone
    Evolution and Ecology, University of California at Davis, CA 95616, USA
    Genet Res 86:31-40. 2005
    ....
  7. ncbi Locus- and population-specific selection and differentiation between incipient species of Anopheles gambiae
    Thomas 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...
  8. pmc Quantitative trait loci affecting phenotypic plasticity and the allometric relationship of ovariole number and thorax length in Drosophila melanogaster
    Alan 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...