Nomadic Enhancers: Tissue-Specific cis-Regulatory Elements of yellow Have Divergent Genomic Positions among Drosophila Species

Nomadic Enhancers: Tissue-Specific cis-Regulatory Elements of yellow Have Divergent Genomic Positions among Drosophila Species: "Author Summary

In order for a gene to be active, it must be turned on, or “expressed.” Instructions determining when, where, and how much a gene will be expressed are encoded by DNA sequences known as enhancers. The precise DNA sequence of a particular enhancer changes over evolutionary time, which may or may not change its effects on gene expression. Many genes are controlled by multiple enhancers and prior work has shown that the location of these enhancers within the genome tends to remain stable for long periods of evolutionary time. Here, we examine the enhancers controlling expression of a gene (yellow) involved in generating pigmentation diversity among fruit fly (Drosophila) species. Surprisingly, we find that not only have the sequence and function of individual enhancers changed among Drosophila species, but so has the location of these enhancers within the genome of each species. This finding is important because it demonstrates a type of evolutionary change affecting DNA sequence elements critical for gene expression that is currently under appreciated and should be considered when searching for enhancers in related species.

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