MRCA Calculator |

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Most Recent Common Ancestor (MRCA) Calculator

This web page realizes HAM Country's CousinCalc's versions 1 and 2. "The theory is that the number of segments, when combined with the size of the segments, can be used to estimate distant relationships. ... Long autosomal segments are unlikely to be from distant relationships, and short segments can either be from close or distant relationships. " -- HAM Country

Step 1: Select Prediction Provider (Default Selected)

Step 2a: Predict using CousinCalc Version 1

Step 2b: Predict using CousinCalc Version 2
From HAM Country: A few things I know about the use of the equation at the moment:
  • This works better on individual segments than it does on sums. Largest segment is good.
  • It still does not work well for cousins less than 1, but this is an improvement.
  • It does not handle "2nd Removed," etc. very well.
  • It is mostly designed to work with values in excess of 3 cMs (use values greater than 3 cMs). Therefore, if you see the wrong value, please check the size in cMs first.

Step 3: View Predictions

Add a cMs value and press the Predict! button.