title: Regulatory changes underlying expression differences within and between Drosophila species.
abstract: Differences in gene expression are an important source of phenotypic variation, and can be caused by changes in cis and/or trans regulation. cis-regulatory variants alter allele-specific expression, whereas trans-regulatory variants influence expression of both alleles in a diploid cell. Because of this difference, we hypothesize that natural selection may favor one type of change over the other. Here, we investigate contributions of cis- and trans-regulatory changes to variable intra- and interspecific gene expression using four strains of Drosophila melanogaster, three strains of D. simulans and a total of 78 genes. We show that cis-regulatory changes account for a greater proportion of the expression differences observed between rather than within species. These data are inconsistent with a neutral model assuming equal probabilities of fixation for cis- and trans-regulatory polymorphisms, suggesting that natural selection influences the molecular mechanisms underlying divergent gene expression. Specifically, cis-regulatory changes seem to accumulate preferentially over time.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA. wittkopp@umich.edu
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Wittkopp
authors.forename: Belinda K
authors.initials: BK
authors.lastname: Haerum
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Clark
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D004330:Drosophila / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017344:Genes, Insect; D008297:Male; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology
chemical_list: D014157:Transcription Factors