Fungi avoid mutation risk during sex

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Fungi avoid mutation risk during sex

Medical Daily Staff Writer | 15 November 2010 @ 11:13 am EST

http://www.medicaldaily.com/news/20101115/3722/fungi-avoid-mutation-risk-during-\

sex.htm

Duke University Medical Center researchers have said that the pathogenic

fungi self protect them during sexual reproduction and stop unwanted genetic

mutations. The mutation risks occur during their mating. The fungal genome

creates a gene-silencing pathway for protection.

This pathway was discovered in Cryptococcus neoformans, a fungus that is

responsible for causing over one million cases of lung and brain infection cases

in humans each year, and more than 600,000 deaths.

A related species, Cryptococcus gattii, is already causing an outbreak in the

Pacific Northwest raising public health concern. " This discovery of how the

genome is protected during sex might be leveraged as an Achilles' heel in the

battle against C. neoformans, which frequently causes life-threatening illness

in people, " said senior author ph Heitman, M.D., Ph.D., chair of the Duke

Department of Molecular Genetics and Microbiology.

" This protective silencing effect also operates in some animals, and our studies

demonstrate that the pathway operates to defend the genome during sexual

reproduction. "

Fungi produce airborne spores during sexual reproduction which are inhaled into

the human lungs and are thought to be the source of many infections.

C. neoformans's defense mechanism is a sex-induced RNAi (RNA interference) that

protects by " silencing " the DNA, so that it is not vulnerable to mutations.