This post is about using DNA testing in an attempt to discover my direct ancestor Thomas Chapman's unknown origins and a bit about the Chapman surname Y-DNA project.
What is DNA testing and how is it used as a genealogy tool? DNA testing and analysis has been a boon for genealogists as it can help confirm or refute relationships in the absence of paper documentation or as additional confirmation of paper documents. There are three types of DNA testing used by genealogists - Autosomal, Mitochondrial (MtDNA) and Y-DNA.
Autosomal testing is the most popular, and gives information on both patrilineal (father's side) and matrilineal (mother's side) descent back about 5 to 7 generations. Any person can take an autosomal DNA test.
Mitochondrial DNA is passed from a mother to her children, so both males and females can take an MtDNA test. This test provides information on the matrilineal line only.
Y-DNA is passed from a father to his sons, so only males can take this test. It provides information on the patrilineal line only.
Archeologists test DNA found in ancient human remains to identify relationships and migration paths from pre-historic times. Genealogists use Autosomal, MtDNA and Y-DNA testing to solve mysteries in their families, such as the biological parents of adoptees, or to determine the accurate male ancestor in a non-paternity event. A non-paternity event is a situation where the presumed father is not the biological father.
What is the Chapman surname Y-DNA project and its goals? The Chapman surname DNA project, started in 2004, is sponsored by the Chapman Family Association (of which I'm a member) with the support of FamilyTreeDNA.com. One of the project's goals is to encourage those with an interest in Chapman genealogy to have a male Chapman in their line have their Y-DNA tested.
In 2004, my dad, Neil Chapman, had his Y-DNA tested hoping it would break down a brick wall with the parentage of his 3rd great grandfather Thomas Chapman (1780-1860). The thinking was that finding a Y-DNA match with another Chapman might indicate a shared ancestor. In 19 years, there have been NO Y-DNA matches with any other Chapmans. There were a small handful of close Y-DNA matches with men who have other, mostly Irish, surnames. These close matches suggest a common ancestor who lived 300 to 600 years ago.
Haplogroup "I" history and migration map. A haplogroup is a genetic population of people who share a common ancestor on either their maternal or paternal line. Haplogroups are named using letters and numbers. As DNA acquires mutations, new haplogroups are named. My Dad's Y-DNA haplogroup is I-M223. To the left is the migration map for the "I" Y-DNA haplogroup. This map is based on Y-DNA testing of ancient human remains. The blue dot labeled Adam is the approximate location of Adam, the earliest known DNA ancestor of all men, who lived between 237,000 and 581,000 years ago. As humans migrated out of Africa, the Y-DNA accumulated mutations, which changed the haplogroup. The Red, Yellow, Orange and Green dots show the location of these child haplogroups as early man migrated out of Africa. The medium blue dot labeled "I" (in present day Turkey) is the first location of the mutation which characterizes the "I" haplogroup. This appeared about 23,000 years ago. As humans continued migrating into Europe and Scandinavia, additional mutations occurred. The I-M253/I-P215 lineages are about 15,000 years old. My Dad's haplogroup, although not shown on this map, is even younger. Dad's haplogroup is frequently found in Britain and Ireland but has also been found in Portugal, France, Germany and Norway. My guess is that there was a paternal ancestor who was originally from Scandinavia (maybe a Viking?) and settled in Britain or Ireland between 700-1000 AD.
Hopefully as more men take Y-DNA tests and chart their ancestors, it will help break down some of these brick walls, such as where my 4th great grandfather Thomas Chapman is originally from and who his parents were.