The Science of Sustainability  Surviving Chromosomal
Rearrangements    • share this article   • Facebook   • Email
Mole voles do fine with one X and no Y  Last blog I talked about
the Transcaucasian mole vole. This little burrowing mammal has
lost its Y chromosome over time. Now both males and females have
only a single X.  I focused on how scientists can't yet figure
out how there are any male mole voles running around. This week,
I want to focus on what this means from an evolutionary
perspective.  These little animals show that massive changes in
chromosome structure can be tolerated and the species can do
quite well. Even when the chromosomal change results in a
significant increase in miscarriages.  About half of a mole
vole's fertilized eggs don't survive to term. Why not? Because
these embryos have either no or two copies of the X chromosome.
Most mammals have two copies of each of their chromosomes– one
from mom and one from dad. At the end of meiosis, each
chromosome copy ends up in a different spe