More on Sex

Well it appears that sex is the topic of the week here--this time in yeast. Given the prevalence of sexual reproduction among organisms on this earth, there must be some purpose or advantage for it. The trouble is that evolutionary biologists have had a hard time figuring out what it is. They've generated hypotheses, but testing them is difficult to do. This is where the yeast come in.

Yeast have the ability to divide asexually, or they can undergo a process of meiosis that results in 4 spores equivalent to gametes (ie. sperm/eggs). Two spores can later fuse to form a dipliod yeast again. In the latest Nature a group has published the results of their experiments comparing yeast that reproduce sexually to those asexually. The sum-up is that the sexually reproducing yeast were better able to adapt to a harsh environment.

For a better and more thorough explanation, see Pharyngula.