Academic research using hundreds of thousands of SNPs from across the genome has shown that human groups generally divide into seven continental populations, which have been established over the past 50,000 years during the migration out of Africa. The 150 populations collected as the ancestry background can thus be divided into these seven continental groups according to their origin.
Snapshot builds on this research by mapping a new person’s genome onto these established populations. Our algorithm calculates how similar the new individual’s DNA is to each of the background populations, determining which population(s) the person comes from. This allows for contributions from multiple groups, so even small amounts of admixture (<5%) can be detected.
Snapshot takes a similar approach to identifying within-continental (regional) ancestry, although the local populations were identified through empirical analysis performed by our bioinformatics team. Each piece of continental ancestry is partitioned according to its regional ancestry (e.g., if an individual is 50% European and 50% East Asian, the precise origin of each of those pieces will be determined). The person’s genome is also plotted against all of the known individuals in each region to show visually where he or she falls.
Below is an example plot for an individual who was determined to be 50% East Asian and 50% Latino. Latino ancestry is a mixture of European and Native American ancestry, so these groups are shown as well.