The often bad effects of inbreeding in animals has long been known. Harmful hereditary traits tend to be common, but in many cases are inactive in an individual unless the trait is received from both parents. The difficulty with inbreeding is that close relatives are much more apt to be carrying identical, detrimental traits in common than are less closely related individuals.
There's a similar situation in plants, and since many plants have
both male and female parts within the same flower, self-fertilization could be a real
problem. After all, that's the ultimate degree of inbreeding. Many plants, though,
have evolved mechanisms that make them sexually incompatible with themselves, with a
sort of a "conversation" taking place between the pistil of the female parts
and incoming pollen of the male. The female bears two genes out of a multitude of
kinds; the pollen bears one. If the pollen's gene matches either of the female
genes, the relationship is doomed. We often hear of pillow talk between human males and
females. So what's this? Pistil talk?
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
McClure, B. 2004. Pillow talk in plants. Nature 429:249-250.