Egg size matters for lizard sex

New findings add a surprising twist to the already complex mechanism that determines whether reptile embryos develop to be males or females. An egg-laying lizard found in the hills of southeastern Australia controls the sex of its young through the size of its eggs, suggesting that female reptiles may actively dole out yolk to fine-tune the sex ratio of their offspring, researchers linkurl:report;http://www.cell.com/current-biology/abstract/S0960-9822(09)01128-2 online today (June 4) in __Curren

Elie Dolgin
Jun 3, 2009
New findings add a surprising twist to the already complex mechanism that determines whether reptile embryos develop to be males or females. An egg-laying lizard found in the hills of southeastern Australia controls the sex of its young through the size of its eggs, suggesting that female reptiles may actively dole out yolk to fine-tune the sex ratio of their offspring, researchers linkurl:report;http://www.cell.com/current-biology/abstract/S0960-9822(09)01128-2 online today (June 4) in __Current Biology__.
Three-lined skink
Image: Sylvain Dubey
The paper "muddies the water" for everything researchers thought they knew about sex determination in lizards, linkurl:Rachel Bowden,;http://www.bio.ilstu.edu/Bowden/ an ecological physiologist at Illinois State University who was not affiliated with the study, told __The Scientist__. "It's clear that they have sex chromosomes. But it's also clear that those sex chromosomes can readily be overridden by some other factors. So, the process that leads to sex determination might be fairly plastic." Sex-determining mechanisms in reptiles can...