Phase I Report on DNA Study
November 4, 2001
by the DNA Study Group
Nick Penington (Chairman),
Paul A. Pennington, Monte Pennington, and John Alan Pennington.
Y chromosome analyses of the first fifteen tissue samples of the PRA DNA Project have been received. Although this small number is too limited to make many conclusions, the analyses do suggest several things.
Before discussing the meaning of the findings of stage one of our study, let us look first at how the study was done and what the analyses look like on the page.
Tissue samples, consisting of cells scraped from inside the cheeks of fifteen volunteers, were submitted to Family Tree DNA, along with the fee for their analysis. These volunteers represented 13 family groups. One analysis was that of a man whose Pennington ancestors were on the maternal side of his family, and thus were not expected to be comparable to the rest. Two of the samples were from family group 28; other Family Groups had only one representative. The Family Groups represented were: 4, 5, 6, 7, 8, 9, 10, 14, 28, 29, 30, 31, and 33.
The analysis we received consisted of number scores for each of twelve markers on the Y chromosome of each person tested. The locations of these markers were designated Locus 1, Locus 2…Locus 12. Each locus is found at a specific place on the Y chromosome, and is also called here a “marker”. We use the term “haplotype”, as well as the term “signature”, to mean the series of twelve numbers seen at these twelve loci. Most of these numbers were single digits. In a future article we will present the scientific notations for each of these markers that are in the public domain, and a more detailed number for each locus of all the tests performed by that time. For the present we will limit our discussion and analysis to the number of variations from the signature of the main group of five haplotypes found in this initial phase.
We limit our discussion here to statistical findings. The significance and ramifications of those findings are primarily up to the Family Group Leaders and any others who may deduce something of significance to the Pennington genealogy from the analyses. The Research Group would like to hear from them.
Interested persons who would like to see what a more complete study looks like may wish to check the online web site for the Mumma family DNA project. In addition, there are numerous articles and books on this very popular topic that can easily be uncovered at the library or your favorite book store.
Now the findings:
- Five of the signatures, representing five different family groups, differ only by one number at Locus 9, which is known for a high mutation rate. Mutations at this locus could be relatively recent. We can safely say that all of these groups share the same Y chromosome signature. The family groups represented are: 5, 7, 14, 30, and 31. The results for Groups 7, 30 and 31 were identical, a 12/12 match. The results for Groups 5 and 14 were identical, a 12/12 match.
- A sample representing family group 4 differs from the above at only Locus 6, suggesting that this family group belongs with the previous five. It is likely that they share an ancestor within the last 1000 years, if not within more recent centuries.
- All other samples vary at two or more markers. Two samples from family group 28 (the only family group so far represented by more than one tissue sample) are identical to each other except at Locus 9, and differ from the first group by two additional markers. This suggests they do share a common ancestor, but their common ancestor with the first group is probably more than 1000 years ago. The same may be said for group 29, represented by a single sample.
- All of the other groups tested vary from the main group at three to ten loci. Groups that vary by three or more markers from the main group are unlikely to share a common ancestor with it as recently as 1000 years ago. These samples represent family groups 6, 8, 9, 10, and 33.
- Groups that vary from the main group by four or more markers may be said to descend from different paternal lines. We can see this is so by comparing the main group signature to the Y signature from the man whose Pennington line is maternal, and therefore does not share the Pennington Y chromosome. His Y chromosome varies by four markers from the main group. However, because we have only one sample representing most family groups, we cannot yet say whether these samples truly represent their family groups.
A sample from Family Group 33 varies by ten markers. It and the other samples that vary by three or more markers from the main group may do so for a number of reasons. One possibility is that they represent distinct lines either older or younger than the currently observed most frequent line. Another is that there has been a “non-paternal event” at an unknown past time. There are several possible types of non-paternal event in addition to a pregnancy gained outside of a marriage. For example, a child may be adopted and given the Pennington name; a man may take the Pennington name when he marries a Pennington daughter; a Pennington man may marry a pregnant woman whose husband has died; a couple where the wife is the Pennington may choose to give their children the Pennington name for various reasons; clerical error in recording administrative data may assign a Pennington name to the wrong person, and so on.
Beyond the conclusion that there appears to be a Pennington haplotype as represented by Family Groups 5, 7, 14, 30, and 31, and probably 4, we are sharply limited in the conclusions we can make because of the limited size of our study sample. We cannot say, for example, that the signature for Family Group 9, which differs from the main group by three markers, is representative of all of the males of Family Group 9, because we have only one analysis from that group. If two additional analyses from that group matched the first we could safely say that it represents a different paternal line. But if a second and third sample instead matched the main group, we could say there was apparently a non-paternal event somewhere within the more recent history of Family Group 9. But we cannot know until additional samples are analyzed.
Nor can we say that the main group in this study pertains to the greatest number of Penningtons or Family Groups. It is well to remember that there are 32 active Family Groups, and that only 13 of those are represented in this study, and only a single family group is represented by more than one person’s analysis. It is possible that what appears in the current study to be the main signature group really only represents one branch, that a line for which we presently have only a single signature actually represents a greater number of family groups. This is suggested by the observation that, of the genetically related Penningtons so far discovered, all seem to have an origin in the Carolinas. We will not know the larger picture until all of the family groups are represented by at least one Y chromosome analysis and perhaps not until there is an even larger database with contributions from all the places on the globe where there are Penningtons.
Now for the Future.
The time has arrived to begin the second stage of the study. The DNA Study Group would like to see every Family Group represented by at least one analysis. Although a second or third analysis from a group already represented would be useful, the primary need at this time is for the unrepresented groups to be analyzed.
The cost for a single Y chromosome analysis is $200 (NOTE: This amount has been lowered to $105 as of 9/26/02). The research committee welcomes checks in that amount from anyone who wants either his own or some other family group’s Y chromosome analysis to be done. But smaller donations in any amount will also be useful, and family group leaders, particularly from unrepresented groups, would do well to seek smaller donations from Family Group members. In addition, the DNA Study Group has several hundred dollars to be used for additional analyses as a result of generous donations by the persons listed below, as well as money pledged by the Board for the project, so far untouched. The best use of donated dollars might be for partial support for a person or family group whose collective donations sums to less than the required dollar amount.
We urge Family Group Leaders to seek donations large and small from their group members. It is particularly important for the unrepresented groups to fund an analysis in order to see where their group lies in the Pennington haplotypes.
It should be reiterated here that some people feel it is important for the identities of volunteers to be protected. We therefore urge all volunteers to keep their participation to themselves, lest someone else’s privacy be accidentally breached.
The DNA Study Group wishes to thank the following sponsors for their generous donations to the DNA Study: Richard Bailey (Family Group 14); Henry B. Hearn III (Family Group 29); Thomas R. Williams (Family Group 8); Joan Flint (Family Group 28); W. Harry Schaffer (Family Group 9?); Christine Borrus (Family Group 28).
Addendum by DNA Study Group Chairman, Nick Penington. - Updated 12/11/01
When the male Y chromosome is analyzed, the majority of the UK population (68%) falls into a large group called Haplogroup 1 (HG1) but in Scotland, Ireland and Wales this rises to 90%. The haplogroup is defined by a set of very slowly mutating groups of bases at locations that reveal deep ancestry, well before surnames were adopted. These classifications are so broad that they are not very useful for family reconstruction studies, such as ours, but knowing your HG can be fun because it appears to correlate with an early tribe of Europe (Saxon, Jute, Dane, Viking etc). It is also useful to the extent that if two Penningtons have different HGs then they must be very distantly related in that they came from different European populations.
The HG can be hinted at by looking at our data, or the 12 numbers that we had measured by FTDNA, for each individual. It turns out that a specific group of 6 repeat numbers tend to occur frequently only in certain haplogroups, thus one can guess from our data, with good confidence, at the HG of the individual; without actually measuring the HG defining mutations.
There is a signature called the “Atlantic Modal Haplotype” (AMH) which is a subset of the group HG1 and is found frequently on the Atlantic coast of Europe. Our results suggest that the six related Pennington groups are almost certainly HG1 (called HG 1.15+). In fact all of our family groups tested so far are HG1, with the exception of Group 33 (HG2, more properly a subset of this group called 2.47+) and Group 6, that we do not know how to classify based on our current understanding. As expected with hindsight, many other families are getting such AMH matches. This means that the other 6 loci that we had tested by FTDNA are the important ones in assigning families to groups with common ancestors. The scientific literature to date suggests that the AMH (and our six related groups) seem to indicate ancestry in the original population of the UK before 800AD. In other words Celts or Ancient Britons.
The result for Group 33 is predicted to be HG 2.47+ and considered likely to be Viking or Norman (considering the part of the UK from which this family originated). A recent genetic survey of the UK population (http://www.bbc.co.uk/history/ancient/vikings/genetics_results_01.shtml) found that although HG 2.47+ was common in Norway it was also present in North Germany from where Anglo-Saxons originated and so differentiation was difficult. Only 18% of the UK population are HG2 but 50% of present Norwegians are HG2. Will any other HG2 Penningtons be found when the other 19 Groups are tested?
Helgason et al American J. Human Genetics 2000, Vol 67, Page 717.
Wilson et al., Proc. Nat. Acad. Sci. 2001, Vol. 98, #9 Page 5078.
Of the 13 Family Groups tested so far, six of them appear to share a common ancestor within the last 500 years or 14 generations, these are Groups 4, 5, 7,14, 30 and 31.
Our results suggest that the six related Pennington Groups mentioned above are almost certainly HG1. In fact all of our Family Groups tested so far are HG1, with the exception of Group 33. This suggests that the Groups for which we have the most data have ancestry in the original population of the UK before 800 AD. These peoples would include the Celts and Ancient Britons. The result for Group 33 is likely to be HG 2.47+ and considered likely to be Norse, i.e. Viking or Norman or less likely but possibly Anglo-Saxon.
It is probable that in the near future that we will all be able to find out which early tribe of Europe our Y-line paternal ancestor belonged to from a few cheek cells! We should remember however that this classification comes from just one man out of several million males who contributed to our individual ancestry.
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Pennington Phylogenetic Tree
by DNA Study Group Chairman, Nick Penington.
Diagram Results from a phylogenetic network analysis program for the first 14 people in our Pennington results. Phylogeny has been defined as "the evolutionary history of a group of organisms, especially as depicted in a family tree." It illustrates how different species are genetically related, but one can use it to show how people with the same surname are related.
The free software used can be found at: http://www.fluxus-engineering.com/sharenet.htm.
Reference is: Bandelt H-J, Forster P, Sykes BC, Richards MB (1995) "Mitochondrial Portraits of Human Populations". Genetics 141:743-753
The diagram helps one to visualize which samples are most closely related. The black numbers in the diagram are our group numbers. Group "A" includes Groups 30,31 and 7 and Group "B" contains Groups 5 and 14. The sizes of the blue circles are proportional to the number of individuals with the same sequence. Remember if ones group is more than one node or step away from another group one probably is not related for about a 1000 years.
The diagram traces possible routes for getting from one haplotype (signature sequence) to another. There are sometimes multiple ways to get from point A to point B, depending on which mutation occurred first. The diagram shows the way that requires the least number of mutations. The length of the line connecting nodes is proportional to the number of mutations required to get from one haplotype to another.
We should all remember also that this figure would change dramatically when more data is added. For instance, if for example Group 10 were to convince 3 "cousins" to take part in our study the diagram would be centered on them rather than group A!
Note that Group 33 is not included on this diagram because I suspect it is a different haplogroup (HG2) and so deserves a separate diagram.
If more HG2 Penningtons were found they would be added to that diagram.
Copyright 12/11/01 Nick Penington