Navigation Links
Yeast missing sex genes undergo unexpected sexual reproduction
Date:5/24/2009

DURHAM, N.C. An emerging form of the pathogenic yeast Candida is able to complete a full sexual cycle in a test tube, even though it's missing the genes for reproduction. And it may also do so while infecting us, according to Duke University Medical Center researchers.

"Sex contributes to the Candida yeast species' evolutionary success," said Joseph Heitman, M.D., Ph.D., director of the Center for Microbial Pathogenesis in the Duke Department of Molecular Genetics and Microbiology and co-author of two papers that tell the story in Nature and Current Biology. "I think the fact that it has a complete sex cycle is likely to play a role in the evolution of drug resistance in this emerging pathogenic yeast species. "

Yeast infections are notoriously hard to treat and yeast are one of the most successful pathogens and commensals in nature, he said. A commensal is an organism that benefits from associating with another organism without affecting the other. Humans are susceptible to three types of yeast infection: thrush (in the mouth and throat), vaginal infection, and a sometimes fatal systemic infection of bloodstream and organs, such as the kidney.

In a paper published online May 24 in Nature, Heitman's team reports that eight Candida species which have a sexual cycle were missing many of the genes related to reproduction found in other species.

"The unrecognized sex cycle could mean we need to develop new treatments to combat what is really happening in humans infected by yeast," said co-author Jennifer Reedy M.D. Ph.D.

With co-author Anna Floyd, Heitman and Reedy explored the question further in a study appearing in the May 14 Current Biology. The major question was: how could the yeast sexually produce spores when they lack so many genes responsible for meiosis, the process of sexual cell division that reduces chromosomes to half their number in the progeny?

By examining and defining the structure and functions of the mating-type genes in yeast, Reedy learned that forms of Candida yeast undergo meiosis but generate offspring of several types. About two-thirds have the classic 50:50 division of chromosomes from the split parent cell, but a third of them have an extra chromosome or even double copies of all chromosomes.

"What we found is that the sexual cycle has a new way to create genetic diversity, and it provides a unique vantage point from which we can explore the mechanisms of sexual reproduction," Reedy said. "This provides a new way to study sexual reproduction and how chromosomal abnormalities arise."

Heitman said that Candida's meiosis without meiotic genes may be what gives rise to the progeny with unusual numbers of chromosomes. "Or maybe the genes were lost for a reason, to provide a route to genetic diversity," Heitman said. "Or maybe these differing types of progeny are the unfortunate consequence of undergoing meiosis without the machinery that species normally have when they reproduce sexually."

Humans, too, have their share of oddly paired chromosomes. "Experts estimate that about 10 to 30 percent of human eggs or fusion products may be aneuploid, with chromosomes from mother and father not paired exactly one to one, but the great majority of those fusions of sperm and egg don't make it to the implantation and pregnancy stage," Reedy said. "That's why it is important to find models like this, so that we may shed light on related human conditions."


'/>"/>

Contact: Mary Jane Gore
mary.gore@duke.edu
919-660-1309
Duke University Medical Center
Source:Eurekalert

Related biology news :

1. Jungle yeast
2. New study reveals the protein that makes phosphate chains in yeast
3. Rhythmic genomics -- the yeast metronome and the walk of life
4. Commercial yeasts upgraded with an enzyme for biofuel production
5. Scientists study full protein content of bakers yeast
6. Genetic differences between yeasts greater than those between humans and chimpanzees
7. Caltech engineers build mini drug-producing biofactories in yeast
8. Gene-environment interaction in yeast gene expression
9. University of Toronto scientists map entire yeast genome
10. UCI and CODA Genomics collaborate to re-engineer yeast for biofuel production
11. Fossil evidence of missing link in the origin of seals, sea lions, walruses found in Canadian Arctic
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/5/2016)... , Feb. 5, 2016 ... of the "Global Facial Recognition Market ... --> http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the ... Market 2016-2020" report to their offering. ... http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the addition of ...
(Date:2/3/2016)... India , February 3, 2016 ... the new market research report "Automated Fingerprint Identification System ... Search, Latent Search), Application (Banking & Finance, Government, Healthcare, ... published by MarketsandMarkets, the market is expected to be ... CAGR of 21.0% between 2015 and 2020. The transformation ...
(Date:2/2/2016)... 2016  BioMEMS devices deployed in hospitals ... medical screening and diagnostic applications, such as ... that facilitate and assure continuous monitoring without ... being bolstered through new opportunities offered by ... coupled with wireless connectivity and low power ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... (PRWEB) , ... February 08, 2016 , ... ... multilingual testing services, announced today the launch of its revamped and improved website. ... scalable language service solutions, the redesigned website will better communicate how the company ...
(Date:2/9/2016)... ... February 09, 2016 , ... The publishing industry ... Access publishing is one of the popular publication models that has received wider ... and 3000+ International Conferences across the globe, OMICS International is ...
(Date:2/9/2016)... and LONDON , February 9, 2016 ... bio tech replace paper and protect IP ... electronic laboratory notebook (ELN) will be rolled out in ... research and development (R&D) and protect valuable IP. Users will ... follow a specific researcher or experiment as part of the ...
(Date:2/8/2016)... 8, 2016 /PRNewswire/ - BIOREM Inc. (TSXV: BRM) ("Biorem" or ... finalists for clean technology companies in the TSX Venture 50 ... companies listed on the TSX Venture Exchange, in each of ... clean technology & life sciences, diversified industries and technology ... to return on investment, market cap growth, trading volume and ...
Breaking Biology Technology: