I can already see the grim look many Americans will have as they chew on their Christmas roast tomorrow. They’ll be thinking about yesterday’s reportthat a cow in Washington state tested positive for mad cow disease. There’s some comfort in knowing that so far it’s just a single cow, and that American cattle are regularly screened for bovine spongiform encephalitis. The grimmest look this Christmas may be on the faces of McDonald’s shareholders and cattle ranchers. A single Canadian cow that test positive wreaked havoc on the entire beef industry up north. But this Christmas also brings a fascinating discovery about the bizarre agents that cause disorders such as mad cow disease: they may actually record our memories.
Evolution isn’t simply about the genes you gain. It’s also about the genes you lose.
I will never figure out the publishing world. My new book, Soul Made Fleshofficially publishes on January 6, 2004. But Amazon and Powell’s both say they’ve got it now and can get it to customers in 1-2 days. I guess time isn’t what it used to be.
Just before the winter solstice brings autumn to an end, here’s a chance to blog about the great evolutionary biologist–and student of fall foliage–William Hamilton. Hamilton, who died in 2000, has never reached the household-name status of other evolutionary biologists such as E.O. Wilson or Richard Dawkins or Stephen Jay Gould. But he deserves a place of privilege, for all his profoundly influential ideas. He found an explanation for altruistic behavior in many insect species by expanding biology’s notion of fitness to include the genes an individual shares with its relatives. He offered one of the best-supported theories for the origin of sex–as a way for a species to keep ahead of its parasites in their evolutionary arms race. And he proposed that sexual displays–such as peacock tails and rooster combs–are signals that males send to females to reveal their ability to fight off parasites and otherwise live well.
Here’sa new development in the search I described last week for the genes that make us uniquely human. Science’s Michael Balter reports on a new study about a gene that’s crucial for making big brains. Mutant versions of the gene produce people with tiny brains–about the size that Lucy had 3.5 million years ago. Comparisons of the human version of the gene with other mammals shows that it has undergone intense natural selection in our own lineage.