I once told someone that in addition to learning about their ancient origins (such as Y-DNA and mtDNA haplogroups), many genetic genealogists would ideally like to match every portion of their DNA with the contributing ancestor.Â Although this might seem to be beyond the reach of current genetic ancestry testing, it has actually already begun.Â The family compare function of 23andMe, for example, is already being used by genetic genealogists for just this purpose; people who have matching DNA segments can compare ancestry and attempt to identify the ancestor who might have contributed the DNA.
For obvious reasons, medical geneticists have for many years been using genealogy to trace founder mutations in populations.Â For example, in 2008 scientists traced a colon cancer gene in the United States to a Mr. and Mrs. George Fry who arrived in the New World around 1630 (see A Single Colon Cancer Gene Traced to 1630).
Tracing A Heart Disease Gene in South Africa
Now, scientists in South Africa recently announced that they had traced a gene responsible for a hereditary heart disease called familial heart block (PFHB) to a Portuguese immigrant who arrived in South Africa in 1696.
From the article:
â€œThe rogue gene was found in three branches of an Afrikaans familial group that can trace its ancestry back to one Portuguese individual who landed on the shores of the Cape at the end of the 17th century.
Prof Andries Brink, former dean of Stellenbosch Universityâ€™s faculty of Health Services, first described the disease in 1977 and published a paper at the time in the South African Medical Journal. The paper, titled Progressive familial heart block â€“ two types, was co-authored by genealogy specialist Marie Torrington.
It was Torrington who discovered that the disease was brought into South Africa by the Portuguese immigrant who arrived in South Africa in 1696. He subsequently married a woman of Dutch descent, and genetics has carried PFHB down all the generations since then. No matter where in the country they live, every South African suffering from PFHB today is descended from that couple.â€
The Journal of Clinical Investigation article is here.