This type of genealogical research has grown tremendously in popularity in the past few years as the costs of the technology and testing have come down, and as the number of people participating in the datasets has increased.
It is used for many things including;
- providing geographic locations for further genealogical research
- helping determine ancestral homelands
- discovering living relatives or paternity/maternity
- validating existing research
- confirming or denying suspected connections between families
- prove or disprove theories regarding ancestry
So what is DNA testing is what has it told us about our families?
Males inherit a specific pieces of DNA only from their fathers (Y-DNA), and both men and women inherit other specific pieces of DNA only from their mothers (mtDNA). So instead of just a random mix of the parent's genes, there is a clear passing on of certain parts of the genetic code between generations which almost never changes. This means there is a continuous lineage that can be traced all the way back into prehistory, linking any living individual to their most ancient ancestors.
Once in several hundred generations, a very minor mutation can occur between parent and child. Because the child will pass on the change, this results in the branching of a new lineage. These mutations can be dated and compared to one another so show the relationships between all human groups. Many lineages are quite recent, while some lineages are very, very old. Some are more numerous, while others are rare. Over the millennia untold lineages have also died out.
Scientists and genealogical organizations have spent the past decade or two building a tree of human lineages and have found that we each can trace our ancestry to specific individuals when new mutations occurred. They have divided up the male lineages and female lineages into many groups, or haplogroups as they are known, each of which branched off from the rest of humanity at different times and locations over the past 140,000 years. There are about 28 Y-DNA and 35 mtDNA haplogroups, with numerous subgroups. By researching the distribution of the haplogroups in modern populations, a picture is being built of ancient peoples and their migrations that were once thought lost to history.
Currently the only haplogroup testing we have for the family was done by Christopher Bretz through Oxford Ancestors in 2005, for both Y-DNA and mtDNA. We hope to collect data from additional family member testing as we can. The haplogroups identified were J2 (Y-DNA) and H2 (mtDNA). Using him as a reference point we can build this haplogroup version of a family tree to show a portion of the family's distinctive genetic lines.
Any direct male descendant of any of the males in this tree would also share the Y chromosome J2 genetic markers. Any immediate and direct male descendant of the females in this tree, or else a direct female descendant would share the mitochondria DNA H2 markers.
Although this data is the only firm testing we have, there are suggestive clues from other family's research on the web.
George surname Y-DNA: There is a study of the George surname in the southern US that strongly suggests haplogroup R1b1b2. This would indicate ancestors which migrated north to England from Spain and southern France at the end of the last ice age. We have not yet been able to find any Georges from Cornwall who have been tested to confirm this.
Halliday surname Y-DNA: There is a study of the Halliday surname which has had mixed results so far, but the Dumfries family branches seem to belong to haplogroup I1. This would indicate ancestors which arrived from Scandinavia, possibly as part of the Viking invasions.
Neilson surname Y-DNA: There is a study of the Neilson/Nelson surname which has also had mixed results so far, which is not entirely surprising given the extant of the name. The few Galloway Neilsons tested appear to belong to haplogroup R1b. This would indicate ancestors which migrated north to England from Spain and southern France at the end of the last ice age.