A mammalian organ that forms inside the mother's uterus, the placenta plays a crucial role during pregnancy. It provides oxygen and nutrients to the unborn baby and removes waste products from the baby's blood.
"Evolutionary biologists have been trying to answer how and why complex organs evolve," Reznick said. "They have also been trying to answer how mating strategies and sexual selection evolve. These may seem like unrelated questions, but our research builds a bridge between them."
Like the eye, the placenta is a complex organ. It is the product of a very large number of genes that must all be well integrated before the placenta can function properly, Reznick explained. "The seeming impossibility of this event is the basis of virtually all of the creation science/intelligent design arguments against evolution," he said.
The new work adds to the growing abundance of evidence about how important parent-offspring conflict the disagreement between parent and offspring over the nature of the parental investment in the offspring is in shaping evolution. This conflict generally increases during parental care, with offspring employing all kinds of strategies to get more from their parents than is in the best interest of the parents to give to them.
"First conceived in 1974, conflict was the product of musings about the coefficient of relatedness between mothers, fathers and offspring," Reznick said. "In the context of our paper, the evolution of the placenta is shaped by conflict, but then its presence creates an ongoing conflict between mother and offspring that has a continuing role in shaping evolution."
An evolutionary theory put to the test
The new work presents for the first time the divers
|Contact: Iqbal Pittalwala|
University of California - Riverside