Guest guest Posted February 19, 2004 Report Share Posted February 19, 2004 For this you need to go back to cell reproduction. Cells make exact replicas of themselves and then split in half leaving them with an exact copy of all the genes in the cell. But that last statement is not true for cells that become eggs and sperm (sex cells). When a sex cell divides it does it twice. First it makes an exact replica of itself and split in two leaving an exact copy of all of the genes in each cell, just like a regular cell's division. Then, it divides again leaving only half of it's genetic material in each cell. This is why a cell from a man can be either X or Y and not both. (Sometimes the cells don't divide in half exactly and this is what causes several other genetic problems that aren't the topic of this list.) This is also why the cf gene can be on either the man's X or Y gene in the same man. It is the luck of the draw, or divide as it were. Dawn mom of 4, 8 and under, the youngest wcf Quote Link to comment Share on other sites More sharing options...
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