Navigation Links
International team compares 12 fruit fly genomes

Cornell researchers have played a major role in an international scientific team that has compared the complete set of genes of 12 closely related fruit fly species. As well has having implications for human health -- from genetic adaptation to evolving immune systems -- the analysis paves the way for better understanding the evolution of each species.

From the results of the research, the Cornell scientists coordinated one of the two papers published this week in the journal Nature. The team, known as the Drosophila12 Genomes Consortium, represented 16 countries and was supported by the U.S. National Institutes of Health National Human Genome Research Institute.

"By looking at a wider number of species, we had much greater power to detect genes and regulatory elements from the way the sequences diverged between species, and to test models of what evolutionary pressures those genes and regulatory elements must have faced," said Andrew Clark, Cornell professor of population genetics and one of the paper's co-authors.

Drosophila (fruit flies) are one of most studied and most important model organisms used in genetics research. Many fruit fly genes are also found in humans and control the same biological functions. As a result, fruit fly research has led to discoveries related to the influence of genes on diseases, animal development, population genetics, cell biology, neurobiology, behavior, physiology and evolution.

The comparative method of this study allows researchers to see which genes have stayed the same and which have diverged, since all 12 species shared a common flylike ancestor some 60 million years ago. The directions in which genes have diverged provide evidence of evolution within each species.

"Methodologically, the study demonstrates the effectiveness of contrasting multiple genomes," said Clark. He and his Cornell colleagues coordinated the evolutionary analysis and worked with colleagues around the world on writing the paper. "It underscores the utility of doing comparative genomic analysis," he said.

In comparing the genome sequences of the 12 species, the team of scientists discovered, for example, that D. melanogaster shares only 77 percent of about 13,700 protein-coding genes with all of the other 11 species. The 23 percent of genes that differ are most likely the ones that have adapted themselves due to environmental pressures and sexual selection. For example, one specialist fruit fly, D. sechellia, eats only one type of fruit and is losing taste receptors five times faster than other fruit fly species that eat a wider range of foods.

Clark said there also is evidence of an evolutionary battle in immune systems of the flies as they repeatedly adapted their defenses against mutating bacteria. As bacteria find new ways to infiltrate a system, species evolve their own new defenses. Most of the genetic changes have been in each fruit fly species' ability to detect and recognize bacteria they confront, Clark said. Although species may respond differently to particular bacteria, overall their innate primary immune responses are similar and even share many features in common with human innate immunity.

One species, D. willistoni, surprised researchers because it had no genes that produce selenoproteins, which sequester selenium, an antioxidant found in many foods and a required mineral for nearly all higher organisms including humans. D. willistoni appears to be the first case of an animal that does not have genes to make selenoproteins, though the researchers cannot rule out the possibility that the species may have another way to encode selenium in its proteins.

Understanding gene regulation: Drosophila continue to offer signs -- and questions

In the cells of the tiny fruit fly (Drosophila), researchers in the 1930s found valuable resources known as polytene chromosomes -- giant bundles of chromosomes, banded into distinct segments corresponding to specific genetic loci.

Polytene chromosomes give geneticists a window on the mechanics of gene activation and transcription, particularly with the advent of new optical and molecular imaging techniques that allow studies of living tissue in real time.

John Lis, the Barbara McClintock Professor of Molecular Biology and Genetics at Cornell, notes in the current issue of Nature that those new studies -- combined with other genetic and biochemical data on Drosophila and mammals -- could lead to a shift in the way scientists understand how gene expression is regulated in cells.

A key question is the regulation of RNA polymerase II (Pol II), an enzyme that binds to DNA and catalyzes the production of messenger RNA. Researchers have long thought that the rate of transcription is limited by the time it takes Pol II to be recruited to the promoter region, where it copies a strand of DNA into RNA. But increasing evidence in Drosophila and other organisms indicates that Pol II frequently exists in a "paused" state at the promoter: Already having made a short RNA, it awaits further regulatory signals before completing transcription. This is leading to new questions about the regulation of transcription.

"The field is changing," said Lis. But many of the answers may still lie with the tiny fruit fly.


Contact: Blaine Friedlander
Cornell University Communications

Related biology news :

1. BIO-key(R) International to Showcase Deployed Biometric Security Applications at 2007 Biometric Technology Expo
2. ESMO International Symposium on Immunology
3. Conservation International and Toyota partner to protect Philippines rain forests
4. International team shows mercury concentrations in fish respond quickly to increased deposition
5. International team shows mercury concentrations in fish respond quickly to increased deposition
6. BIO-key(R) International to Showcase Deployed Biometric Security Applications at 2007 Biometric Technology Expo
7. Youngstown, Ohio Police Award Mobile Data Contract to BIO-key(R) International
8. Clemson physicist addresses international forum on thermoelectric energy
9. US launch of international consultation for new responsible nanocode
10. International team of scientists warns of climate changes impact on global river flow
11. BIO-key International Showcasing Innovative Public Safety Solutions at 2007 IACP Conference
Post Your Comments:
(Date:11/16/2015)... , Nov 16, 2015  Synaptics Inc. (NASDAQ: ... interface solutions, today announced expansion of its TDDI ... touch controller and display driver integration (TDDI) ... smartphones. These new TDDI products add to the ... resolution), TD4302 (WQHD resolution), and TD4322 (FHD resolution) ...
(Date:11/12/2015)... LONDON , Nov. 11, 2015   ... and reliable analytical tools has been paving the ... and qualitative determination of discrete analytes in clinical, ... sensors are being predominantly used in medical applications, ... and environmental sectors due to continuous emphasis on ...
(Date:11/10/2015)... About signature verification Signature ... identify and verify the identity of an individual ... secure and accurate method of authentication and is ... because each individual,s signature is highly unique. Signature ... signature of an individual is compared and matched ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... , Nov. 24, 2015 Halozyme Therapeutics, Inc. (NASDAQ: ... Conference in New York on Wednesday, December ... Helen Torley , president and CEO, will provide a corporate overview. ... New York at 1:00 p.m. ET/10:00 a.m. PT . ... investor relations, will provide a corporate overview. --> th ...
(Date:11/24/2015)... Global, Inc., a worldwide provider of clinical research services headquartered in ... company has set a new quarterly earnings record in Q3 of ... for Q3 of 2014 to Q3 of 2015.   ... with the establishment of an Asia-Pacific office ... Kingdom and Mexico , with the ...
(Date:11/24/2015)... , November 24, 2015 ... recent market research report released by Transparency Market Research, ... expand at a CAGR of 17.5% during the period ... Testing Market - Global Industry Analysis, Size, Volume, Share, ... global non-invasive prenatal testing market to reach a valuation ...
(Date:11/24/2015)... ... November 24, 2015 , ... InSphero AG, the leading supplier of easy-to-use ... promoted Melanie Aregger to serve as Chief Operating Officer. , Having joined ... management team and was promoted to Head of InSphero Diagnostics in 2014. ...
Breaking Biology Technology: