25-Marker Matches

What happens if/when we have 25-marker matches?

Well, the good news is that 25-marker matches allow finer interpretations:

· 24-25/25: You share a common ancestor, probably within a genealogic time frame. (The numbers of generations & dates below are approximate.)

¨ A perfect 25/25: The chances are 90% that your most recent common ancestor is within the past 28 generations, roughly since 1300 AD. It’s 70% that the time to the most recent common ancestor (TMRCA) is within 15 generations >= 1630 AD and 50% the TMRCA is <= 9 gen., >= 1780 AD. Thus, as we will find out when we look at greater numbers of markers, discovering a "perfect" 25/25 match only means that you share an ancestor who lived about 1300 (90% probability) to 1780 (50% probability).

A 24/25 match means even less. 24/25: The 90% probable TMRCA is <=48 gen, >= 800 AD; 70% is <= 30 gen., >= 1260 AD; 50% is <= 21 gen., >= 1480 AD.

Matching 23/25 may not illuminate your genealogical studies at all, as your common ancestor may have preceeded records with surnames. 23/25 or worse: You share a common ancestor, but he may not have lived within a genealogic time frame

Looking at this in terms of generations, instead of years, the match of 23/25: 90% TMRCA is <= 67 gen., >= 330 AD; 70% is <= 46 gen., >= 860; AD; 50% is <= 34 gen., >= 1160 AD.

While a 22/25 match means even less. 22/25: 90% TMRCA is <= 86 gen., >= 140 BC; 70% is <= 61 gen., >= 480 AD; 50% is <= 47 gen., >= 830 AD.

Input from Ralph Taylor and Lalia Wilson