Probability distribution of time to MRCA: Y Chromosome markers

Two individuals with 35 exact matches, 2 matches off by one, no matches off by two

A service of Family Tree DNA.

Current Version: 22 November 2003.

Main TMRCA page --- All the very technical details

Method: B. Walsh, 2001. Estimating the time to the MRCA for the Y chromosome or mtDNA for a pair of individuals, Genetics 158: 897--912

Mutation rate: The time calculations are highly depend on both the mutation rate and model assumed. As our knowledge of these grows, the pages will be updated to reflect these changes, including allele-specific rates. For now, we use an average value for the mutation estimates. You can also see the effect of assuming mutation rates at the upper and lower ends of the current estimates.

Click below for Times for Your Desired mutation rate (u)

Standard mutation rate (u = 0.002)

How to read these cumulative probability plots and tables

Method 50% 90% 95% 95% Confidence Interval
Infinite Alleles 19 37 44 4-50
Stepwise correction 19 38 46 4-53

High mutation rate (u = 0.004)

How to read these cumulative probability plots and tables

Method 50% 90% 95% 95% Confidence Interval
Infinite Alleles 9 18 22 2-25
Stepwise correction 9 19 23 2-27