The X in Sex: How the X Chromosome Controls Our Lives

In his fourth-century BCE Generation of Animals, Aristotle wondered what made us into males and females, and the question has vexed scientists ever since. Bainbridge (Making Babies) shows that the answers are at last partly illuminated, thanks to advances in our understanding of the mechanisms at work in sex chromosomes. He debunks once and for all Aristotle's notion that maleness, and hence the Y chromosome, is a more active, superior state of being, and instead hails the X chromosome as more profound, interesting and powerful--not just more than its""sad, shrunken"" Y counterpart, but more than any other chromosome in our cells. First explaining how the sex chromosomes--which he calls the ""seeds of sexiness""--turn undifferentiated embryonic tissue into testicles or allow the formation of ovaries, Bainbridge goes on to demonstrate how the X chromosome is actually in control of the process. Examples throughout the animal kingdom and instances of humans with anomalous chromosome lineups (like XXY or XO) show X's role in sex determination, autoimmune and sex-linked diseases. Bainbridge also reveals how women's cells""deal with the double bounty of X chromosomes,"" why girl identical twins are less identical and less rare than boy identical twins, and how studying women's tumors showed scientists that cancer begins in a""lone, fatal"" cell. With first-rate research and winning, dry wit, Bainbridge crafts a slim volume of science made simple. 4 line illustrations