Dr. Gleason's research focuses on molecular evolution, behavioral genetics, and the evolution of courtship song in Drosophila.
Sexual isolation- the reluctance of males and females of different species to mate with each other- can be a major cause of speciation in many animals. How many genes must change to produce sexual isolation? Some argue that species differences must involve change across many genes, perhaps hundreds, but the recent application of molecular techniques for gene mapping is suggesting, surprisingly, that single genes can play a large role in many ecologically important traits.
Identification of genes affecting behavior is difficult; behavioral traits can be time consuming to measure and are prone to environmental influences. Although researchers have found mutations in single genes that affect behavior, it is not clear whether or not these genes are involve in variation within species or in species differences. In addition, most behaviors are quantitative traits and, therefore, must be influenced by multiple genes. For these reasons, I am using quantitative genetics to examine natural variation within and between species.
Drosophila is an ideal model system for behavioral genetic analysis because the genetics of the organism are so well known and because it has reliably performed, quantifiable behaviors. My research uses two species that do not normally mate with each other. These species differ in female cuticular hydrocarbons (detected by the males) and male courtship songs (produced by wing vibrations and heard by females). Through quantitative trait loci analysis on backcross individuals, we can measure the cosegregation of these traits with molecular markers. Preliminary results indicate that songs are polygenic, but surprisingly are influenced by genes of major effect that are probably not those identified in single gene mutation analyses. Cuticular hydrocarbon composition is affected by one major locus, previously implicated, but other loci play a role in addition.
- 2012. "Genotype x environment interaction, environmental heterogeneity, and the lek paradox" Journal of Evolutionary Biology. 25. 601-613. .
- 2012. "Different sensory modalities are required for successful courtship in two species of the Drosophila willistoni group" Animal Behaviour. 83. 217-227. .
- 2009. "Identification of quantitative trait loci function through analysis of multiple cuticular hydrocarbons differing between Drosophila simulans and D. sechellia females" Heredity. 103. 416-424. .
- 2008. "Reaction norm variants for male calling song in natural populations of Achroia grisella (Lepidoptera: Pyralidae): Towards a resolution of the lek paradox" Evolution. 62(1317-1334). .
- 2005. "Quantitative trait loci for a difference in cuticular hydrocarbons between Drosophila simulans and D. sechellia associated with sexual isolation" Genetics. 171. 1789-1798. .
- 2005. "Mutations and natural genetic variation in the courtship song of Drosophila" Behavior Genetics. 35. 265-277. .
- 2004. "Do quantitative trait loci for a courtship song difference between Drosophila simulans and D. sechellia coincide with candidate genes and intraspecific QTLs?" Genetics. 166. 1303-1311. .
- 2004. "DNA preparations from fly wings for molecular marker assisted crosses" Drosophila Information Service. 87. 107-108. .
- 2003. "Analysis of a shift in codon usage in Drosophila" Journal of Molecular Evolution. 57. S214-S225. .
- 2002. "Quantitative trait loci affecting a courtship signal in Drosophila melanogaster" Heredity. 89. 1-6. .
- 2001. "mtDNA variation and GIS analysis confirm a secondary origin of geographic variation in the bushcricket Ephippiger ephippiger (Orthoptera: Tettigonioidea), and resurrect two subspecies" Molecular Ecology. 10. 603-611. .
- 1999. "Drosophila song as a species-specific mating signal and the behavioural importance of Kyriacou & Hall cycles in D. melanogaster song" Animal Behaviour. 58. 649-657. .
- 1998. "Evolution of courtship song and reproductive isolation in the Drosophila willistoni species complex; do sexual signals diverge the most quickly?" Evolution. 52. 1493-1500. .
- 1998. "A molecular phylogeny of the Drosophila willistoni group: conflicts between species concepts?" Evolution. 52. 1093-1103. .
- 1997. "Variability of the bushcricket Ephippiger ephippiger: RAPDs and song races" Heredity. 79. 286-294. .
- 1997. "Mitochondrial DNA phylogenies for the Drosophila obscura group" Evolution. 51. 433-440. .
- 1997. "Interspecific and intraspecific comparisons of the period locus in the Drosophila willistoni group" Molecular Biology and Evolution. 14. 741-753. .
- 1996. "Codon usage and the origin of P-elements" Molecular Biology and Evolution. 13. 278-279. .
- 1996. "A molecular phylogeny for the Drosophila melanogaster subgroup and the problem of polymorphism data" Molecular Biology and Evolution. 13. 1224-1232. .
- 1995. "Rapid evolution of courtship song pattern in Drosophila willistoni sibling species" Journal of Evolutionary Biology. 8. 463-479. .
- 1993. "Rates of DNA evolution in Drosophila depend on function and developmental stage of expression" Genetics. 133. 291-298. .
- 1992. "Complementary DNA-DNA hybridization in Drosophila" Journal of Molecular Evolution. 34. 130-140. .