The identification and phylogenetic position of I-Y33765

In 2017, YFull.com, the Y-chromosome sequence identification service, identified and named the I-Y33765 SNP when comparing the BAM files of FTDNA Big Y-500 test results for two men who shared the Clement surname and had earliest known direct male ancestry during the eighteenth century in the parish of Compton Greenfield, south Gloucestershire, England. At that time the mutation was one of ten novel SNPs identified in these men downstream of I-Y4252.

In February 2020, the same mutation was found in an FTDNA Big Y-700 test taken by a man named Jacobsson with seventeenth century direct male ancestry in Tjust, Småland, Sweden. Subsequently two other men named Eklund and Dahlberg with seventeenth and eighteenth century ancestry in Tjust and Kinda, Småland, Sweden have been confirmed with the marker (see map). From comparison of the English and Swedish results, and using their estimated Y-chromosome mutation rate, YFull calculate that Y33765 formed about 670AD.  At present it seems probable that this happened somewhere in southern Scandinavia possibly in Småland, south east Sweden, and perhaps in the hundred of Tjust.

 

The chart (below) summarizes the relationship between the five men who were known to be derived for I-Y33765 in April 2020.