Some maladies are cause by chromosomes being deleted (see Prader-Willi). How does that work?
In: 6
There are normally 46 chromosomes in human cells. When eggs and sperm cells are manufactured, half the chromosomes are removed to leave only 23. The 23 in the sperm and 23 in the egg add up to 46 chromosomes, which is how you inherit genes from both your mother and father. Sometimes in the process of forming the sperm or egg cells, the process malfunctions, leaving the wrong number of chromosomes, either more or less than the normal 23. If these abnormal sperm or egg cells happen to win the lottery and start a pregancy, then there is the potential for a genetic condition caused by abnormal chromosome count. Most of these conditions are fatal to the zygote before the pregnancy is noticed, but in some cases an abnormal chromosome count can still result in a viable pregnancy.
Latest Answers