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University of Iowa News Release


Nov. 18, 2011

Photo: Researchers are using varieties of the New Zealand freshwater snail, Potamopyrgus antipodarum, in a study comparing sexual reproduction to asexual reproduction. Credit: Bart Zijlstra.

Researchers receive NSF grant to study evolutionary consequences of abstinence

Why do living organisms engage in sexual, rather than asexual, reproduction?

That question will be investigated by Maurine Neiman, assistant professor of biology, and John M. Logsdon Jr., associate professor of biology -- both in the University of Iowa College of Liberal Arts and Sciences -- along with collaborator Jeffrey Boore of the University of California, Berkeley, and CEO of Genome Project Solutions, Inc., thanks to a 4-year, $876,752 grant from the National Science Foundation.

It turns out that answering the question may be more complicated than it appears.

Neiman says that the commonness of sex is surprising because asexual females should be able to produce twice as many daughters as sexual females that make both male and female offspring. "Because only females can directly produce offspring, the production of sons by sexual females creates a two-fold 'cost of males' that should culminate in the rapid elimination of sex," she notes.

Despite this and other costs, nearly all organisms reproduce sexually at least some of the time. This means that sex must be associated with profound advantages, while asexual reproduction must have significant evolutionary consequences.

Neiman, Logsdon, and Boore will use high-throughput genomics -- advanced DNA sequencing technologies that rapidly generate massive amounts of DNA data from genomes -- to compare the nuclear genomes of sexual and asexual varieties of a New Zealand freshwater snail, Potamopyrgus antipodarum. The research will test ideas for why sexual reproduction persists, including the hypothesis that sex is needed to prevent the buildup of harmful mutations.

An earlier study by Neiman and Logsdon of the much smaller mitochondrial genome found that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails.

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