Adventures in Y-Chromosome DNA Testing

Of the 23 pairs of chromosomes in every cell of our body, only the Y chromosome is male-specific. Biological males will have a copy of this chromosome together with one copy of X. Females on the other hand have two copies of X. The X and Y chromosomes are referred to as the sex chromosomes. The other 22 chromosome pairs are the autosomals and they encode all of the proteins that make us human. Y contains about 60 million base pairs (60 Mbp) of DNA and encodes 50 – 60 genes; the most critical, SRY provides instructions for making a protein called the sex-determining region Y protein. This protein is essential for male sexual development. 

Of particular interest to genealogists, a large portion of Y does not encode any genetic information at all and plays more of a role in the physical structure of the chromosome. And most fortunately for us, the vast majority of Y does not recombine with the other autosomes. When mutations do arise, they occur in the form of short tandem repeats (STRs) or single nucleotide polymorphisms (SNPs).  These are passed down directly from father to son in a direct male line of descent from prehistoric days to the present. Assuming no "non-paternity events" such as name changes, bastard sons, adoption, etc., a particular Y lineage can be traced back genetically tens of thousands of years ago. Amazing!

Due to the rate of mutations in STRs, they are useful for determining the relatedness of males in genealogical time frames (~500 years to the present). Whereas SNPs are useful for determining relatedness in anthropologic time frames (tens of thousands of years to the present). In most western cultures, males inherit their surname from the biological father. In medieval England before the Norman Conquest, communities were small and individuals usually only had a first name or nickname. But the Norman leaders taking over Britain after 1066 introduced the concept of hereditary surnames. As these names developed, many were derived from the geography of the local terrain. These are known as toponymic or topographical surnames. While others could be related to the male’s occupation or family status as "son of".

In genealogical time frames the Lunsford or Lunceford surname is ancient and English. It is possibly related to the Luxford surname as well. Most contemporary research indicates that the ancestral family originated in the Sussex area of southern England and may be derived from the Norman/French Lundesford family. Regardless, for US-based genealogies, Y testing can help us confirm paper records and potentially afford a way to link together various separate twigs of our family tree.

At present, Baldwin is our earliest known ancestor. We have very little information on his parentage or local origins. That is why I would like to conduct a basic Y analysis on his lines (both the Anna Ball and Judith Creel lineages). This should confirm (or not) living  males as being direct paternal descendants of Baldwin. Once that is accomplished, then we can compare our family genetic profile to that of other Lunsford/Lunceford/Luxfords clans in the US and Europe and perhaps link us all together in some way. 

A preliminary DNA analysis of my Y chromosome indicates that I am a member of the I1 haplogroup. You can read all about the theoretical derivation and ancient history of this chromosome here. It is primarily Nordic/Germanic.

A DNA study is especially important for our Baldwin lineage because I am aware of other US-based Lunsford/Lunceford researchers that have done extensive DNA research on their twig of the tree. They are members of the R1b haplogroup. Definitely European with a strong English geography, but a completely different beast in genetic terms.

While there are some examples of disparate haplogroups occurring in a common surname, it is rare and normally indicates either distinct chronological origins or some kind of previous non-paternal event. Only additional testing on living males can settle this type of thing.

A note of caution on autosomal DNA testing available from Ancestry.com, Family Tree DNA and others: these tests look at the 22 autosomes and can show you very recent genealogical events (usually around five generations back or less with any meaningful accuracy). They are fun for the novice and aimed squarely at the general public. They provide a rough approximation of geographic origin and heritage from both the paternal and maternal lines. Except for finding lost parents and first or second cousins (especially if you are adopted and looking for your birth relatives), they are of little value for serious paternity and surname studies going back to medieval times or later. 

The human chromosome spread was from the National Library of Medicine/NIH. Haplogroup maps were taken from Eupedia. Click on them for larger images.

R. Dwayne Lunsford, PhD