Dr. H. Allen Orr proposes three related projects concerning the genetics of speciation in this amended application for a FIRST award. There is considerable debate as to whether the initial stages of reproductive isolation result from a few major genes or a large number of genes of smaller effect. While studies have typically found a modest number of factors involved in isolation, essentially all of these studies have relied on taxa separated for some time, making it difficult to distinguish between initial events and those occurring much later during the evolution of isolation. Dr. Orr proposes to examine an evolutionary """"""""young"""""""" taxa, the """"""""Bogota"""""""" subspecies of Drosophila pseudoobscura. Dr. Orr has already studied the genetics of isolation for this subspecies at the whole chromosome level, finding evidence for a very strong epistatic interaction between normal pseudoobscura second and third chromosomes with the X chromosome from the Bogota population. The proposed work will use at least 32 mapped markers to much more finely examine how many separate chromosomal regions are involved in isolation. The second project proposed is to examine specific predictions on the nature of a hybrid rescue mutation, which restores the viability of normally inviable species hybrids. Dr. Orr proposes two specific tests of the Hmr (Hybrid male rescues) gene, namely that deletion of Hmr+ will also rescue hybrids, while addition of Hmr+ kills normally-viable hybrids. These predictions follow from the model proposed by Hutter, Roote, and Ashburner that Hmr is a loss-of-function allele at a locus otherwise involved in hybrid inviability. The final project is a screen for mutants that rescue hybrid fertility in crosses of D. melanogaster and D. simulans. While mutants what rescue hybrid viability are know (such as Hmr), there are no mutants that rescue fertility and apparently no one has screened for such mutants. The investigator proposes three screens based on using individuals from natural populations, from EMS mutagenized-flies, and from a P-element mutagenesis screen.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29GM051932-03
Application #
2415274
Study Section
Genetics Study Section (GEN)
Project Start
1995-05-01
Project End
2000-04-30
Budget Start
1997-05-01
Budget End
1998-04-30
Support Year
3
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Rochester
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
Ahmed-Braimah, Yasir H (2016) Multiple Genes Cause Postmating Prezygotic Reproductive Isolation in the Drosophila virilis Group. G3 (Bethesda) 6:4067-4076
Alfonso-Parra, Catalina; Ahmed-Braimah, Yasir H; Degner, Ethan C et al. (2016) Mating-Induced Transcriptome Changes in the Reproductive Tract of Female Aedes aegypti. PLoS Negl Trop Dis 10:e0004451
Ahmed-Braimah, Yasir H; Sweigart, Andrea L (2015) A single gene causes an interspecific difference in pigmentation in Drosophila. Genetics 200:331-42
McNabney, Daniel R (2012) The genetic basis of behavioral isolation between Drosophila mauritiana and D. sechellia. Evolution 66:2182-90
Phadnis, Nitin (2011) Genetic architecture of male sterility and segregation distortion in Drosophila pseudoobscura Bogota-USA hybrids. Genetics 189:1001-9
Sweigart, Andrea L (2010) Simple Y-autosomal incompatibilities cause hybrid male sterility in reciprocal crosses between Drosophila virilis and D. americana. Genetics 184:779-87
Orr, H Allen (2010) The population genetics of beneficial mutations. Philos Trans R Soc Lond B Biol Sci 365:1195-201
Sweigart, Andrea L (2010) The genetics of postmating, prezygotic reproductive isolation between Drosophila virilis and D. americana. Genetics 184:401-10
Betancourt, Andrea J (2009) Genomewide patterns of substitution in adaptively evolving populations of the RNA bacteriophage MS2. Genetics 181:1535-44
Unckless, R L; Orr, H A (2009) Dobzhansky-Muller incompatibilities and adaptation to a shared environment. Heredity (Edinb) 102:214-7

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