On the previous page is given an outline of the Hamilton Surname DNA Project along with procedures for potential participants to follow. On this page a few more details of the project are given. Also, an attempt is made to articulate why each of you should consider having a DNA analysis done for your Hamilton line and how the results could assist you in tracing your family history

In this study 12, 25 or 37 markers (the 25 or 37 marker test is recommended) in the DNA of the Y-chromosome of each sample are examined. The Y-chromosome is unique in human DNA in that it is only found in males and is passed down from father to son virtually unchanged. The term 'virtually' is used because there is a small probability (less than 1 %) that a mutation will occur in the markers each generation. The net result then is that the markers being examined will have essentially the same (or very similar) values for you, your father, grandfather, great grandfather, etc., back many generations (10 to 50 or more). Obviously one cannot directly analyze such DNA back more than 2 or 3 generations because earlier ancestors have passed on. However, the power of the technique is that one does not have to analyze the DNA of ancestors; one can obtain meaningful genealogical information by comparing the results from your DNA analysis with the results from others. Consider, for example, that your direct male ancestor of say 10 generations ago had 2 sons, one of whom you are descended from, and the other who is the ancestor of another group of Hamiltons. The Y-chromosomal DNA from a living direct male descendant of the second son should be identical or very similar to your Y-chromosomal DNA. The corollary of course is that, if neither you nor the other Hamilton knew your lines back that far, finding your DNAs to be so closely matched would indicate that you have a common ancestor. That could open up new avenues for both of you to explore. Of course, if you find that your Y-chromosomal DNA does not match that of another Hamilton one could conclude that you are not closely related (at least through the Hamilton male line).

It should be emphasized that the analyses for this study can only be done on samples collected from males since they are the only ones with the Y-chromosome. Furthermore, because the Y-chromosome is passed from father to son the study can only find relationships that occur through direct male lines. Since surnames usually follow direct male lines, our study has the potential to find many relationships among various Hamiltons. Those of you who are females with Hamilton ancestors can still participate in the study if you find a male relative (father, brother, uncle, male cousin, etc.) who is willing to supply a sample for analysis. By the way, sample collection is painless; it involves merely rubbing the inside of the cheek with a foam brush collector.

One should point out that there are several situations where the DNA analysis might give an unexpected result. These are sometimes referred to euphemistically as 'non-paternal' events. Some examples of such situations are: an unknown adoption in your line, an illegitimate birth or conception out of wedlock, some ancestor taking the surname of a stepfather, etc. Of course, if you have suspicions that one of these might have occurred in your line, obtaining a DNA analysis and comparing the results to those of presumed relatives where it is unlikely such an event happened could provide evidence whether such an event has occurred in your line.

Many of us have been able to determine our Hamilton lines back to the 18th or 19th century (4 to 8 generations or so) but have been stymied in trying to trace our lines back further. Using DNA analyses one has the potential to be able to obtain information about earlier generations. For example, suppose you have a well documented Hamilton line back to about 1830 in Tennessee. You suspect that your earliest known Hamilton ancestor migrated to Tennessee from either Virginia or North Carolina but have not been able to make the connection. You know that there are several known Hamilton lines in Virginia and North Carolina so it seems a reasonable possibility. By having the DNA from one of your Tennessee Hamiltons analyzed and comparing the results to those obtained from the various Virginia and North Carolina Hamilton lines, one would obtain evidence which one is the most likely to be related to your line, and thus you would know where to focus further traditional genealogical research.

One of the general questions the Hamilton DNA study has been able to address is whether virtually all Hamiltons come from a common ancestor (say 500 to 1500 years ago) or whether there were several different initiating ancestors. The results to date suggest that there were several initiating ancestors. It is believed that most Hamiltons originated in Scotland, although, prior to emigrating to the new world, many had previously migrated to England or been transplanted from Scotland to Ireland, especially in the 17th century. In early Scotland there is a very well documented Hamilton lineage starting with Walter Fitzgilbert in the late 13th century. This line led to many Dukes, Earls, Barons, etc. and for that reason is well documented. Undoubtedly many other Hamiltons, including many who ultimately emigrated to the new world, are unknowingly derived from this line. By comparing the Y-chromosomal DNA of such individuals with the DNA from well documented descendants of the ducal line one could conclude with a high degree of certainty whether they come from the same line or not. Eventually the DNA study will be able to identify members of this line but currently it is still not clear what the markers for this line are. In any event, there are too many people with the Hamilton surname in the world for us all to be derived from the Walter Fitzgilbert line and the results to date tend to bear this out. Where did the other Hamilton lines originate? Walter Fitzgilbert's main seat of power was in an area near Glasgow, Scotland and surnames did not come into common use in that area of Scotland until the 14th or 15th century. About that time the descendants of Walter Fitzgilbert came to be known as Hamiltons and the town (now a city) that grew up around their castle (or palace) was given the name of Hamilton. It is suspected that when surnames came into common use some of the retainers or servants who lived in Hamilton and worked for the ducal Hamilton line just took the surname Hamilton. That could be the reason that there were several initiating ancestors who have given rise to the various current Hamilton lines. In any event, the DNA study will help to clarify how widespread the taking of the Hamilton surname was.

In order to answer the question how many initiating Hamilton ancestors there were, one will need broad participation by many Hamilton lines. For this reason alone, each of you with a Hamilton line is encouraged to participate in this study. However, a potential added benefit from participation is that some more immediate questions may be resolved in your line (see earlier discussion) and that you may find totally unexpected relationships with other Hamilton lines. Several new relationships have already been found from the results obtained to date.

Written, Jan 2006. Last updated January 2024