DNA

DNA (deoxyribonucleic acid) is the primary source of inherited information used in bodily development. A single molecule of DNA combined with protein makes up each of the 46 chromosomes contained in most cells of the human body. The reproductive cells, sperm and ova (eggs), each contain 23 chromosomes so that, at conception, the fertilized ovum (now called a zygote) contains 46 chromosomes. Thus, we inherit about half of our DNA from our fathers and about half from our mothers.