Lizard Moms Choose the Right Genes for the Right Gender Offspring

Two Dartmouth biologists, Cox and Calsbeek, have come to terms that a specific lizard known as the Brown Anole are apart of the deciding process with choosing which males father their offspring. In fact, the females produce more sons when mating with larger males and more daughters with smaller males. These two biologists believe that the lizards do this to ensure the genes from the larger males are passed on to the sons, who naturally benefit from inheriting the genes for larger size. The species has figured out how to pass down the genes with specific effects on fitness and how to get these right genes within the right gender. When the female lizards mate with males of different sizes, it is proved that their choice of preference is larger males. However, when their choice of partners were limited to smaller males, they minimized the production of sons. In order to demonstrate this to be true, Cox and Calsbeek measured the survival rates of the sons and daughters in their natural habitat in the Bahamas. They happened to find that the survival of the male offspring increased if they had large fathers; although, there was no influence from the larger fathers passed down to the daughters, proving that only the survival of the male offspring only increased if they had they larger fathers. Although these studies are legit, there is no true answer to how these female lizards control the gender of their offspring.

http://www.biologynews.net/archives/2010/03/04/lizard_moms_choose_the_right_genes_for_the_right_gender_offspring.html