Abstract
Drosophila pigmentation has been a fruitful model system for understanding the genetic and developmental mechanisms underlying phenotypic evolution. For example, prior work has shown that divergence of the tan gene contributes to pigmentation differences between two members of the virilis group: Drosophila novamexicana, which has a light yellow body color, and D. americana, which has a dark brown body color. Quantitative trait locus (QTL) mapping and expression analysis has suggested that divergence of the ebony gene might also contribute to pigmentation differences between these two species. Here, we directly test this hypothesis by using CRISPR/Cas9 genome editing to generate ebony null mutants in D. americana and D. novamexicana and then using reciprocal hemizygosity testing to compare the effects of each species’ ebony allele on pigmentation. We find that divergence of ebony does indeed contribute to the pigmentation divergence between species, with effects on both the overall body color as well as a difference in pigmentation along the dorsal abdominal midline. Motivated by recent work in D. melanogaster, we also used the ebony null mutants to test for effects of ebony on cuticular hydrocarbon (CHC) profiles. We found that ebony affects CHC abundance in both species, but does not contribute to qualitative differences in the CHC profiles between these two species. Additional transgenic resources for working with D. americana and D. novamexicana, such as white mutants of both species and yellow mutants in D. novamexicana, were generated in the course of this work and are also described. Taken together, this study advances our understanding of loci contributing to phenotypic divergence and illustrates how the latest genome editing tools can be used for functional testing in non-model species.
| Original language | English |
|---|---|
| Article number | 184 |
| Journal | Frontiers in Ecology and Evolution |
| Volume | 8 |
| DOIs | |
| State | Published - Jun 30 2020 |
Bibliographical note
Publisher Copyright:© Copyright © 2020 Lamb, Wang, Simmer, Chung and Wittkopp.
Funding
We thank Arnaud Martin (George Washington University) as well as Kathy Vaccarro and other members of Sean Carroll’s laboratory (University of Wisconsin) for advice on CRISPR/Cas9 genome editing and Drosophila injections, respectively; Hannah McConnell, Aida de la Cruz, and Harmit Malik (Fred Hutchinson Cancer Research Center) for sharing their experience working with the nanos promoter in Drosophila virilis ; and the Bloomington Drosophila Stock Center as well as the National Drosophila Species Stock Center for maintaining and providing fly stocks. Funding. This work was funded by the National Institutes of Health (Grant Nos. 1R35GM118073 and 1R01GM089736) awarded to PW; National Science Foundation Graduate Research Fellowship Program (Grant No. DGC 1256260) and National Institute of Health training grant: “Michigan Predoctoral Training in Genetics” (Grant No. T32-GM07544) to AL; and startup funding provided by the Michigan State University AgbioResearch to HC.
| Funders | Funder number |
|---|---|
| Kathy Vaccarro | |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | DGC 1256260 |
| National Institutes of Health (NIH) | T32-GM07544, 1R35GM118073, 1R01GM089736 |
| Michigan State University AgBioResearch |
Keywords
- abdominal pigmentation
- Cas9
- CRISPR
- genome editing
- melanin
- nanos
- virilis group
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Ecology