Toxoplasma, that mind-altering, cell-manipulating, all-around awesome parasite that sits in the brains of billions of us, is back in the news. Infection with the parasite raises the chances a woman will have a boy from 51% to 72%. The average ratio of boys to girls at birth is 51%. Women with high levels of antibodies to Toxoplasma, scientists found, have a 72% chance of having a boy. While many effects of Toxoplasma probably have something to do with adaptations that allow the parasite to thrive and spread successfully, this one seems more like a side-effect, albeit a dramatic one.
Author: Lori Jia
The Seed in-house blog, Page 3.14 has been running Q & A’s with some of its bloggers. Mine’s up now.
Originally published October 10, 2006. Copyright 2006 Carl Zimmer.
Two years ago this month, I was taken aback by some explosive news. A team of Indonesian and Australian scientists reported that they had discovered fossils of what they claimed was a new species of hominid. It lived on the island of Flores in Indonesia, it stood three feet tall, and it had a brain about the size of a chimp’s. Making the report particularly remarkable was the fact that this hominid, which the scientists dubbed Homo floresiensis, lived as recently as 18,000 years ago. I wrote up a post on the paper, and took note of some strong skepticism from some quarters. And since then, I’ve found myself devoting a number of posts to the new papers from the discoverers of Homo floresiensis, and the emerging responses from the skeptics–so many that I gave them their own category.
This morning it was announced that two American scientists won the Nobel Prize in Physiology and or Medicine, for their 1998 discovery of a hidden network of genes. It may seem odd that a network of genes could lurk undiscovered for so long. But the cell is very much a mysterious place. In the 1950s, scientists established the basic model for how genes work. A gene is made of DNA, the cell makes a single-stranded copy of a gene in a molecule called RNA, and it then uses the RNA as a template for building a protein. This so-called Central Dogma proved to be correct for many thousands of genes, but not all of them.
PZ Myers did an excellent job yesterday of dismantling the latest from intelligent-design advocate Jonathan Wells. Wells wrote a piece on WorldNetDaily called “Why Darwinism is Doomed.” It is based some new research identifying an important gene involved in the human brain–which I blogged about last month. Wells claims that this discovery is a serious threat to evolution. Why? Because scientists have only just found the gene, because many genes are involved in building the human brain, and because finding a gene that’s different in humans than in other animals doesn’t actually reveal what caused that difference. Myers shows why all three arguments are wrong.