Local Ancestry
Definition
Local ancestry refers to segments of an individual’s genome that can be traced back to ancestors from different populations living in different places and at different times. Certain genetic variants are more common in people from some regions of the world than others. Throughout the genome, genetic variants are physically co-located together in segments called haplotypes. In the genome of a person with ancestry recently derived from people in many regions of the world, each of these haplotypes may contain genetic variants that represent from which one of the regions their ancestors lived.
Narration
A person’s genetic ancestry at a specific location in their chromosome is their local ancestry. Let's say an individual has ancestors from South America, Europe, and Asia. Some of these ancestors could have been great, great, great, great, grandparents. The living person may not even know about these ancestors, but their genome would have segments that were present in these distant relatives. Genomic variants that were close to each other in the genome of the ancestors may still be grouped (linked) together in the living person. Knowing about these groups of genomic variants (or haplotypes) can provide more information about the person’s ancestry than individual genomic variants. In many cases, seemingly unrelated individuals with the same linked set of variants share a distant common ancestor. Measuring these linked sets of genomic variants allows for more accurate tracing of genetic ancestry.
