Perspectives Online

Artificial selection of mating behavior results in larger-than-expected changes to fruit fly genes

Dr. Trudy Mackay (holding a vial containing her research subject, the fruit fly) has made significant recent discoveries about genomic responses to artificial selection.
Photo by Becky Kirkland

Research by N.C. State University geneticists has found that artificially promoting certain traits in an organism can result in major changes to the organism's genome, or set of all genes.

Dr. Trudy Mackay, William Neal Reynolds Professor of Genetics, and research colleagues at N.C. State made the unexpected discovery while studying the mating behavior of the model research organism Drosophila melanogaster, or fruit fly.

The research showed that after 29 generations of mating quick-copulating males and females while also separately mating slow-copulating males and females - thereby artificially selecting for mating behavior - 21 percent of the genome changed between the fast-mating flies and the slow-mating flies. That is, 3,727 genes in the genome - which contains more than 14,000 genes - had differing levels of activity when comparing slow-mating flies and fast-mating flies.

The research results are published online in Proceedings of the National Academy of Sciences.

Mackay said the results were surprising; she and her colleagues expected the percentage of changed genes would be well less than a few percent of the genome. But, she said, the results could lead to clues to the biological puzzle of speciation, in which breeding organisms diverge into two groups incapable of breeding.

"Artificial selection has been used to improve crop science and to improve animal species; the more general question now is, 'What are the genomic responses to artificial selection?'" Mackay said. "Our results suggest the changes are a lot larger and more profound than we previously thought."

After 29 generations, the slow-mating flies took two and sometimes three hours to mate while the fast-mating flies generally mated within 20 minutes, the research showed.

Mackay said the females in the slow-mating lines became more selective through succeeding generations.

"The slow lines were slow because the females became very picky; they wouldn't mate with males from their (slow) line or the fast line," Mackay said.

"The study results could parallel what appears in nature when signals between males and females become unrecognizable," Mackay said. "The questions we want to ask now are 'Why are the females picky?' and 'What is changing in the picky females?'"

The research was funded by grants from the National Institutes of Health.

- NCSU News Services

Geneticist Trudy Mackay named Fellow of American Academy of Arts and Sciences
Dr. Trudy F.C. Mackay, William Neal Reynolds Distinguished Professor of Genetics in the College of Agriculture and Life Sciences, has been elected a Fellow of the American Academy of Arts and Sciences for her outstanding contributions to genetics.

With Mackay's election, N.C. State University now has three faculty members among the approximately 4,000 Fellows.

The award is the third prestigious acknowledgement of Mackay's work in the past three years. She was named an American Association for the Advancement of Science (AAAS) Fellow in 2003 and received the Genetics Society of America Medal in 2004.

Mackay specializes in studying the genetic and environmental factors affecting variation in quantitative, or complex, traits. Her groundbreaking work in the study of quantitative trait loci, or the locations in the genome where variations occur, focuses on two model organisms - Drosophila melanogaster, the fruit fly, and Arabidopsis thaliana, mustard weed.

- NCSU News Services

Valid XHTML 1.0! Valid CSS! Summer 2005 Contents | Communication Services | CALS