Eastern & Western house mice took parallel evolutionary paths

The European house mouse has invaded nearly every corner of the Americas since it was introduced by colonizers a few hundred years ago, and now lives practically everywhere humans store their food.

Yet in that relatively short time span — 400 to 600 mouse generations — populations on the East and West Coasts have changed their body size and nest building behavior in nearly identical ways to adapt to similar environmental conditions, according to a new study by biologists at the University of California, Berkeley.