Language
English
Publication Date
10-7-2024
Journal
G3
DOI
10.1093/g3journal/jkae176
PMID
39073776
PMCID
PMC11457094
PubMedCentral® Posted Date
7-29-2024
PubMedCentral® Full Text Version
Post-print
Abstract
When adaptive phenotypic variation or quantitative trait loci map within an inverted segment of a chromosome, researchers often despair because the suppression of crossing over will prevent the discovery of selective target genes that established the rearrangement. If an inversion polymorphism is old enough, then the accumulation of gene conversion tracts offers the promise that quantitative trait loci or selected loci within inversions can be mapped. The inversion polymorphism of Drosophila pseudoobscura is a model system to show that gene conversion analysis is a useful tool for mapping selected loci within inversions. D. pseudoobscura has over 30 different chromosomal arrangements on the third chromosome (Muller C) in natural populations and their frequencies vary with changes in environmental habitats. Statistical tests of five D. pseudoobscura gene arrangements identified outlier genes within inverted regions that had potentially heritable variation, either fixed amino acid differences or differential expression patterns. We use genome sequences of the inverted third chromosome (Muller C) to infer 98,443 gene conversion tracts for a total coverage of 142 Mb or 7.2× coverage of the 19.7 Mb chromosome. We estimated gene conversion tract coverage in the 2,668 genes on Muller C and tested whether gene conversion coverage was similar among arrangements for outlier vs non-outlier loci. Outlier genes had lower gene conversion tract coverage among arrangements than the non-outlier genes suggesting that selection removes exchanged DNA in the outlier genes. These data support the hypothesis that the third chromosome in D. pseudoobscura captured locally adapted combinations of alleles prior to inversion mutation events.
Keywords
Animals, Chromosome Inversion, Drosophila, Gene Conversion, Genomics, Quantitative Trait Loci, Genetics, Population, Selection, Genetic, Chromosome Mapping, Chromosomes, Insect, inversion, selection, local adaptation, Drosophila pseudoobscura
Published Open-Access
yes
Recommended Citation
Stephen W Schaeffer, Stephen Richards, and Zachary L Fuller, "Genomics of Natural Populations: Gene Conversion Events Reveal Selected Genes Within the Inversions of Drosophila pseudoobscura" (2024). Faculty and Staff Publications. 5987.
https://digitalcommons.library.tmc.edu/baylor_docs/5987