RIVERSIDE, Calif. A research team, including UC Riverside biologists, has found experimental evidence that supports a controversial theory of genetic conflict in the reproduction of those animals that support their developing offspring through a placenta.
The conflict has been likened to a battle of the sexes or an arms race at the molecular level between mothers and fathers. At stake: the fetuss growth rate and how much that costs the nutrient-supplying mother.
The new research supports the idea of a genetic arms race going on between a live-bearing mother and her offspring, assisted by the growth-promoting genes of the father.
The research is described in a new paper, the cover story of the July 24 issue of the Proceedings of the National Academy of Sciences.
Part of the significance of the research is in providing experimental proof of a theory put forth in the 1990s that holds that in animals with a placenta, genetic material from the father and the mother promote different growth rates in the embryo, producing a conflict over nutrients.
The placenta is a complex organ of maternal and fetal tissues that nourishes the developing fetus in the uterus.
Most mammals, excluding marsupials like the kangaroo and the koala, have a placenta. Because of the placenta, a developing embryo remains longer inside the mother (in marsupials, early development of the newborn occurs in the mothers external pouch).
Evidence to support the conflict over nutrients theory has been found in placental mammals. But the new study is the first to look for this conflict in a species other than mammals that also have evolved placental reproduction.
We worked with the fish family Poeciliidae and other families in the order Cyprinodontiformes, which included the poeciliids, said David Reznick, a professor of biology at UCR and a leading authority on live-bearing fishes, who provided all of
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Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside
31-Jul-2007