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Desert Diary


We've all heard of X and Y chromosomes and how they determine the sex of a person. That is, receiving an X chromosome from each parent results in a girl, but getting a Y from the father results in a boy. So much for the old tradition of blaming the woman if she didn't produce a son and heir!

Be that as it may, this is not a universal situation. Among our birds, for example, things are reversed, and it's the female who has the XY condition, although to prevent confusion with the mammalian setup, we call it ZW. Or take a look at our desert grasshoppers. The female grasshopper has two X chromosomes just as in ourselves. The male grasshopper, however, only has one sex chromosome—the other is missing entirely and so we label him as XO. As if all of this wasn't mind-boggling enough, environment plays a part in some animals. In some reptiles, male or female depends on what temperature the eggs are subjected to. No wonder we find matters of sex confusing!
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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.