IBD sharing rates by cM length

The plots below are from 100,000 pairs of simulated relatives of the indicated relationships. Note that segment detectors are never perfect—they may include false positive segments and will not always detect real segments that two people share (i.e., will have false negatives). Because of this, it’s important to use caution when interpreting these numbers: the simulator only provides perfect segments. See the original blog post that describes this analysis for motivations and details on how we did this.

Relationship abbreviations: 1C represents first cousins, 2C second cousins, etc., and NC1R represents Nth cousins once removed. For half relationships, we use the letter h as a prefix, so h2C represents half-second cousins; hAV is half-avuncular, so a half-aunt-nephew pair, for example.

Select the minimum cM length to plot:
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