Probability distribution of time to MRCA: Y Chromosome markers

Two individuals with 23 exact matches, 2 matches off by one, 0 matches off by two

A service of Family Tree DNA.

Current Version: 30 June 2002.

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 28 56 66 6-75
Stepwise correction 29 59 71 6-82

High mutation rate (u = 0.004)

How to read these cumulative probability plots and tables

Method 50% 90% 95% 95% Confidence Interval
Infinite Alleles 14 28 33 3-38
Stepwise correction 14 30 35 3-41