![Click to enlarge Image](/image/s1/34173/100304142245.jpg)
© Joseph MehlingThe male of this species can be two to three times the mass of the female, but the females seem to be in control of the genetic destiny.
Two Dartmouth biologists have found that brown anole lizards make an interesting choice when deciding which males should father their offspring. The females of this species mate with several males, then produce more sons with sperm from large fathers, and more daughters with sperm from smaller fathers. The researchers believe that the lizards do this to ensure that the genes from large fathers are passed on to sons, who stand to benefit from inheriting the genes for large size.
The study is published in the March 4 issue of
Science Express, the advance online publication of the journal
Science.
"This species has figured out a clever way to pass on genes with gender-specific effects on fitness," said Bob Cox, the lead author on the paper and a post-doctoral researcher at
Dartmouth in Hanover, N.H. "Usually, when natural selection pulls genes in different directions for each gender, the species faces an evolutionary dilemma. But these lizards have solved this puzzle, they've figured out how to get the right genes into the right gender."