Scientists have found a clue to why one type of DNA is passed down to children via their mothers rather than fathers. It's always been know that mitochondria is carried only on the mother's side, but exactly why has not been clear. New research is now shedding light on this process.
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 inScience. A protein called CPS-6 slices away 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 could actually be a danger to developing embryos, the researchers say. Using electron microscopy, the team at the University of Colorado at Boulder was able to see the process and how it changes the cells.