The average human being has 46 chromosomes containing 25,000-30,000 genes that are in each cell’s nucleus that contain. However, reportedly there are 37 special genes located in mitochondria, energy factories also located in the cell nucleus. For years it was believed that the DNA contained in these 37 genes was transmitted to a fetus exclusively from the mother. It apparently is not completely clear the reason that the father’s maternal DNA does not seem to transfer to the fetus, although research has indicated that sperm cells have a gene that triggers the destruction of paternal mitochondria when fertilization occurs. In 2002, one case of biparental mitochondrial DNA was found in one man in his skeletal muscle cells but was thought perhaps to be a fluke or the result of a contaminated specimen because the mitochondrial DNA in his other tissues was exclusively maternal. It was not believed that it was even possible for maternal and paternal mitochondrial DNA to even co-exist in humans. More tomorrow.