Protein destroys contribution from dad’s sperm, study in worms shows
Q. Zhou et al/Science 2016
Scientists have found a clue to why one type of DNA is passed down to children by their mothers — but not their fathers.
DNA inside energy-producing organelles called mitochondria is destroyed in a dad’s sperm shortly after it fertilizes an egg, researchers report online June 23 in Science. A protein called CPS-6 cuts apart the mitochondrial DNA in the male sperm so that the DNA can’t make the proteins that the mitochondria need to power the cell. Lingering paternal mitochondrial DNA might hurt developing embryos, the researchers say.
“This is a very long-standing mystery in biology — why in so many organisms, [only] the maternal mitochondria are inherited,” says Ding Xue, a geneticist at the University of Colorado Boulder who led the work.