"In humans, men have an X and a Y chromosome, and women two X’s. "
"Birds....... it’s the male that has two of the same chromosomes. Their sex chromosomes are called the Z and W, with males having two Z’s and females a Z and a W."
http://www.nytimes.com/2010/07/20/science/20chicken.html?_r=0
"Birds....... it’s the male that has two of the same chromosomes. Their sex chromosomes are called the Z and W, with males having two Z’s and females a Z and a W."
http://www.nytimes.com/2010/07/20/science/20chicken.html?_r=0
