That doesn’t tell us who the common ancestor is but confirms there was one. Further, one particular marker, called DYS-460, appears to be a very good indicator of Boonies vs. Boonies have ten repeats at this location while Billies have eleven, at least for the testers with known lineages to the American immigrants and their English cousins.īig Y testing is an entirely different test. It looks at SNPs – Single Nucleotide Polymorphisms – pronounced “snips.” These are the more fundamental building blocks of DNA, the particular nucleic acid at a given location on the DNA molecule. By carefully examining the sequence of the nucleic acids at about fifty million locations along the chain we can detect changes (mutations) from the baseline signatures. There is no negative connotation implied by the word mutation. They occur randomly but unlike the STR changes, there are no back mutations. The change is propagated forward in all the subsequent descendants. To illustrate this process, consider the family tree shown in Figure 1. The figure shows a family progenitor, Thomas, with two sons, John and William. Thomas will pass SNP A to each of his sons who will in turn, pass it to each of their sons. Now imagine new SNP B forms in John at his conception.Īll of Thomas’ direct male descendants will carry SNP A (forever). John will pass SNP B to his sons, thus both George and David will carry SNP A from Thomas and SNP B from John.
In a similar manner, imagine new SNP C forms in William.
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