For all those who have wondered where they'd be without their mothers, a study reported in the February Cell Metabolism, a Cell Press publication, puts a whole new spin on the question. Mice whose mothers pass along a mutant copy of a single imprinted gene can't keep themselves warm and die soon after leaving the comfort of the nest. The findings also reveal that the babies require a second round of heat-generating brown fat to survive.
"When that second wave is delayed, it gets them in the end," said Anne Ferguson-Smith of the University of Cambridge.