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Tuesday, 12 January 2010

Since European settlement, 60 per cent of Australia's native rodent species have become extinct or threatened with extinction.  Researchers at The University of Western Australia aim to gain a better understanding of sperm competition, sexual conflict and gamete evolution in mice, which may help to conserve remaining native rodents.

With almost $400,000 funding from an Australian Research Council Discovery Project grant, Dr Renee Firman and Professor Leigh Simmons of UWA's Centre for Evolutionary Biology will examine the reproductive systems of different mouse species.  One such species is the Sandy Island mouse, a species found in the Pilbara where there are high levels of mining activity.  Unlike the solitary house mouse, the native mice are communal, sandy in colour and with bigger ears.

Dr Firman said more is known about sperm competition in insects than in mammals. This new project will further knowledge about mating in vertebrates generally, and thus may have benefits for the treatment of infertility in humans.

The researchers hope to discover the mechanisms by which the sperm of genetically superior males have greater success in sperm competition.  Dr Firman plans to travel to Spain to the Museo Nacional de Ciencias Naturales this year to learn a novel in vitro fertilisation assay technique.  The sperm of different males is stained different colours, and then the success of each male is scored against his competitors via observing the sperm and ova under a fluorescent microscope.

In previous work, Dr Firman found that house mice evolving with sperm competition produce ejaculates with more sperm and better sperm motility compared to males evolving without sperm competition.  Additionally, female house mice mated to three males - polygamy - produce larger litters than females mated to a single male - monogamy.  Thus, she has provided evidence that sperm competition is a potent selective force that shapes the evolution of male ejaculates, and provides reproductive benefits to females.

Dr Firman's future work will include investigations into sperm competition in native mice, and compare the reproductive systems of introduced (house mice) and native (Sandy Inland) mice.

Media references

Dr Renee Firman (+61 8)  6488 2699  /  (+61 4) 39 099 587
Janine MacDonald (UWA Public Affairs)  (+61 8)  6488 5563  /  (+61 4) 32 637 716

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