Studies have established that several mitochondrial DNA mutations exist in the developing egg cells of human embryos, but the level of mutations are very low. It has been found in the experiments that egg cells in healthy females all carry a few defects in their mitochondrial DNA. Inheritance of most of the mutations is prohibited in sexual reproduction through the combination of egg and sperm. But the mutations are passed down unchanged from the mother due to the asexual replication of the mitochondria.
How is it that a healthy mother can pass on mutated mitochondrial DNA to all if...
Rachel's Story A mothers' account of raising a transgendered child Rachel's mother is the author of this story. She writes about the first few years of Rachel's life when she was known as Ryan. This is the story of how Ryan became Rachel. Rachel is a beautiful, well-adjusted, happy and healthy nine year old little girl. She likes to do all the things little girls at this age like to do. Sleepovers and ice-cream sundaes are by far her favorite...