CHAMPAIGN, Ill., July 12 (UPI) -- Eastern chipmunks living today in Illinois and Wisconsin appear to have descended from ancestors who survived the last North American ice age.
University of Illinois researchers analyzed the mitochondrial DNA of 244 chipmunks and found the majority of them had ancestors who probably survived the last ice age in isolated pockets of forestland amid the cold tundra.
They found 78 of 95 genetically similar groups identified in mostly Wisconsin and Illinois clearly descended from survivors in the west and north, closer to the Wisconsin glaciation. Over time, these chipmunks migrated south from the colder region, merging with chipmunks that migrated into the region from the warmer east and south.
The researchers took DNA from tissue from the very tip of an ear of each chipmunk after the animals were captured in live traps. The chipmunks were released at the same sites of their capture.
