What is the advantage of the 25 marker test over the 12 marker test?
More markers reduce the number of generations to the MRCA (Most Recent Common Ancestor). If you match someone on 12 of 12 markers, you probably share a common ancestor. If two people match 25 of 25 markers, the odds are about 1,000,000 to one that the two are related. The question becomes “how far do you have to go back to find that common ancestor?” If all 12 markers match, there is a 50% probability that the MRCA is 14.4 generations or less, a 90% probability that the MRCA is 48 generations or less and a 95% probability that the MRCA is 62 generations or less. For 12 identical markers,95% of the possible values fall between 1 and 77 generations. If all 25 markers match, there is a 50% probability that the MRCA is 7 generations or less, a 90% probability that the MRCA is 20 generations or less and a 95% probability that the MRCA is 30 generations or less. For 25 identical markers, 95% of the possible MRCA values fall between 1 and 44 generations.
More markers reduce the number of generations to the Most Recent Common Ancestor (MRCA). If you match someone on 12 out of 12 markers, you probably share a common ancestor. If two people match on 25 of 25 markers, the odds are about 1,000,000 to 1 that the two people are related. The question becomes “how far back do you have to go before you find that common ancestor?” If all 12 markers match there is a 50% probability that the MRCA is 14.4 generations or less, a 90% probability that the MRCA is 48 generations or less, and a 95% probability that the MRCA is 62 generations or less. For 12 identical markers, 95% of the possible MRCA values fall between 1 and 77 generations. If all 25 markers match, there is a 50% probability that the MRCA is 7 generations or less, a 90% probability that the MRCA is 20 generations or less, and a 95% probability that the MRCA is 30 generations or less. For 25 identical markers, 95% of the possible MRCA values fall between 1 and 44 generations. Click here
