USING STRs for intra-family Y-DNA comparisons: segmenting markers
ABSTRACT: Counting Y-DNA STR differences is a poor discriminator for members of the same family. Unless a very large number of markers are used, matching cannot be used with a statistically significant degree of accuracy to establish whether someone is more closely related even to second cousins. However – there are other methods that may be used to distinguish degrees of relatedness. We present a simple and useful test which involves finding a “segmenting marker” which can establish relative consanguinity with some accuracy, and we give a real-life example of its use to show from which of two 17th Century brothers a man of unknown origins descended.