What happens when a mutation occurs in the Y-Chromosome?
When a mutation occurs at one of the markers that we are examining, the number of repeats will increase or decrease, usually by one. For example, a father who is DYS19 = 10 may encounter a mutation at the level of his sperm which will change the DYS19 into 11 (an increase of 1). This new DYS19 is then introduced to his son, who will then pass the DYS19 = 11 to all of his sons. A mutation normally happens when the polymerase which copies the DNA in our body makes a slight mistake and does not copy the original exactly. All changes are then passed on to further generations. Mutations are extremely rare. The chances that a single Y-Chromosome marker will mutate is approximately once in every 500 generations. In a situation where 44 markers are examined, we would expect to see one mutation occurring in any one of the 44 markers every 11.4 generations (divide 500 by 44). The presence and detection of such mutations while you are conducting your research will allow you to determine how close
