Exploring Genealogy
with
Special
Guest
Thomas H. Roderick, PhD
Transcript of Chat -
22 May, 2001
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| <Roderick> | It could be done. Bone does retain DNA |
| <Wurts> | Yes, DNA analysis on the bone, to substantiate other's bonafide descendancy. |
| <Roderick> | If you have your Wurts ancestor's toe, a lab could probably do a Y chromosome DNA analysis. I wouldn't count on it, but it might be possible, depends on how long ago. Anyway inquire of the labs that are doing Y chromosome analysis. |
| <Roderick> | mtDNA is easier to find in ancient bones because there is so much more of it in us. |
| <Roderick> | Another way to find out if you have connections with a distant Wurts ancestor is to find other male descents from that man and check their Y chromosome DNA with yours. If there is a match, at least your Wurts families are monophyletic, i.e. descending from the same common Wurts ancestor |
| <Roderick> | whether it is the man with the pinky toe or not is not proved, but would be supported. |
| <CG> | When 2 men or a group of men find out that they have identical Y-DNA, how long ago did their common ancestor live? |
| <Roderick> | I'm guessing, but would suggest within the last 10,000 years. Some DNA sites mutate faster than others. If an appreciable amount of the Y chromosome were analyzed then one could say the relationships were closer. |
| <Roderick> | That is a very good question, which I should be able to answer easily for both mtDNA and the Y chromosome, but I can't at the moment. |
| <Roderick> | Further on the BYU answer. I understand that the information both pedigree and blood will be 'anonymized' (a new verb) that is all information as to name will be expunged from the records, so no one can break the code. The initial study requiring at least 4 generations of pedigree on all sides, will |
| <Roderick> | be used to search for connections, and associations with ethnic or national groups. With that information then one can go back and look at individuals and give them clues as to genealogical origins. |
| <Roderick> | The initial study, however, is "anonymized" so as to protect the identity of blood donors. There are legal implications if otherwise, and I doubt the study would have been approved if this had not been done. |
| <Roderick> | The ethical problems arise because some DNA variants could suggest that an individual had a particular genetic disease or a predisposition to the disease. If that were known by an employer or an insurance company, either or both might be denied. |
| <Roderick> | For the most part the mtDNA analysis will NOT be associated with genetic disease because the DNA analysis is done in a region without specific genes. Also true for the Y chromosome. |
| <JMBeidler> | Tom, in answer to earlier questions, you said that mtDNA and Y chromosomes would show an umbilical relationship going back 10,000 years. Can time frame of the common ancestor be pinpointed more closely than that? If so, how does that work? |
| <Roderick> | Again, it depends on how much of the mtDNA or Y chromosome is analyzed and compared. Professor Bryan Sykes in his analysis, identifies the DNA in the mtDNA at about 400 sites, and says, if one that is if NO difference occurs, between you and another, then your umbilical lines intersect somewhere before 10,000 years ago. If you have 1 difference, then over 10,000 years ago, 2 differences, over 20,000 years ago. |
| <Roderick> | I recommend his little book, one he edited with several |
| <Roderick> | authors, called The Human Inheritance, Genes, Language and Evolution, Oxford Univ. Press 1999. |
| <Roderick> | He is coming out with another book on mtDNA ancestors, which one can order before publication on Amazon.com |
| <Roderick> | We as humans share over 99%% of our DNA in common. That's amazing really in that we all look so different from one another. It is that fraction of one percent that makes us look different. But we are all one species to be sure. |
| <JMBeidler> | What I'd be looking for is a way to pinpoint a relationship 200 years ago vs. say 500 year ago. Am I dreaming about this possibility? |
| <Roderick> | I don't think it is dreaming. It's a great question, and I must do some more digging. If anyone does have further questions don't hesitate to contact me directly at roderick@acadia.net |
| <Roderick> | There are computer programs for analyzing distance of relationships based on |
| <Roderick> | 1. the number of sites that are different |
| <Roderick> | 2. and the known mutation rates at each of those sites. |
| <Roderick> | Clearly if a site mutates rapidly it will be better as an indicator of recently relationship. But if it doesn't change for hundreds of thousands of years, it is a better indicator of our deep genealogical past. |
| <Roderick> | All that has to figure in. |
| <Wurts> | Relative to my earlier question ... From a tissue sample from an umbilical female descendant, is there a way to do a subtractive comparison, with molecular DNA or other means, to determine the ""print"" of the DNA from the spouse of the immigrant? |
| <Roderick> | If your genealogical work is good, and you have proved your connection with an immigrant ancestress, that is an umbilical immigrant ancestor |
| <Roderick> | then YOUR mtDNA should match probably identically with that ancestor. |
| <GenieJunkie4DNA> | ? Does it make it better or does it make it more complicated if your lines carry kissing cousin lines |
| <Roderick> | Cousin relationships would have no bearing on the umbilical line. It is interesting how really few generations we have to go back to find cousin marriages. We lose ancestors fast that way. We should have 1024 ancestors 10 generations back, but I doubt anyone anywhere has that many. |
| <Roderick> | Does anyone have a different interpretation of the BYU study? |
| <BeccaRose> | so aside from the genealogical inferences, what other benefits are there from a study like this? What other goals and objectives did you have when you set out (or have you since discovered)? |
| <BeccaRose> | I'm referring to your study not the BYU study |
| <Roderick> | We had hoped we might contribute to a better understanding of the mutation rates in the mtDNA. |
| <Roderick> | If for example we had numerous connections and we could be assured that the mtDNA matched for the most part in each of those connections, then IF we found one change, it would be a mutation |
| <Roderick> | Then we would have a numerator and a denominator and begin to get estimates of mutation rates. |
| <Roderick> | I think our data would be very few compared to the many studies going on, so perhaps we do not have aspirations of contributing to that phase of the study. |
| <GenieJunkie4DNA> | I have heard that you're a Number and no one has access to this coded book except Scott WOODWARD |
| <Roderick> | That could be. I thought Dr. Woodward told me no one could break the code. |
| <DNACousins> | I looked for the most distant cousin I could find who should have the same mtDNA. Oxford Ancestors report showed we matched. Our common ancestor was born in 1794. |
| <Roderick> | In Oxford ancestors, you have about 400 sites, do you not? |
| <DNACousins> | Yes, Oxford Ancestors reports on 400 sites. |
| <Roderick> | Also they give you the general "tribe" that you come from, 8 or so, am I correct, and did you come from the common European one? |
| <Roderick> | One can look at oxfordancestors.com on the internet and see a description about the several tribes. |
| <Roderick> | 'tribe' in this case referring to distant genealogical connections. |
| <DNACousins> | Yes, I came from a branch off the common tribe ""Helena"", my husband from ""Xenia."" |
| <Roderick> | Dr. Sykes gives exotic female names to these tribes. |
| <Roderick> | There you are |
| <Guest1684> | Although I can see how this kind of study might help in 7 or 8 generations at this point it seems like a lot of conjecture and guessing not sound Genealogy |
| <Guest1684> | ROFL, I didnt realize I forgot to sign on as Uncle Hiram |
| <Roderick> | I think it would be a mistake to use these approaches other than in a confirmation of |
| <Roderick> | genealogical studies done in the time honored ways using primary sources. I gave an example in my paper on this site of using a genetic problem to help to prove a genealogical connection between a mother and a presumed daughter who were 50 years apart, not impossible. |
| <Roderick> | In the future, I suspect that genealogical and heredity societies will have the opportunity of sending in Y chromosome or mtDNA evidence to support descents and over all genealogical work. |
| <Roderick> | If your umbilical ancestor is Priscilla Mullins, then we ought to confirm it nicely by testing other umbilical descents from Priscilla, of which there are probably hundreds. There are several questions of descent from Mayflower passengers hat could be disproved by mtDNA analysis or supported by same. I am trying to put a collection of these together. |
| <Guest1684> | So basically you agree with me that at this point you are only laying the foundation not really viable for current genealogical research? |
| <Roderick> | For example, I gave you the case of my maternal grandfather whose umbilical line probably leads back to a Native American lady. This conjecture passed down through 4 lines of descent |
| <Roderick> | There are all kinds of reasons, genealogically to think it is true, including a photograph of one of her sons who looks like a cross between an American Indian and a Caucasian. |
| <Roderick> | But the mtDNA would prove it. I think that kind of evidence is bonafide genealogical evidence. |
| <JMBeidler> | IF I might chime in, I would say to Guest1684 that, especially in the case of Y chromosome research, this could have a particular advantage over ""sound Genealogy"" in primary sourcees that might be wrong - i.e., a son named in a will who was not that father's biological son |
| <Guest1684> | Respectfully I would disagree, It would prove Indian heritage but Not to a specific line |
| <Roderick> | BUT yes, the mtDNA is only inherited from mother to daughter to daughter etc. to sons as well, but the sons don't pass it on. |
| <Roderick> | This is the ONLY line under consideration. His umbilical ancestral line leads directly to this presumed Mohawk lady. |
| <Roderick> | If this is not clear, I am sorry I have not made the general point clear. |
| <Roderick> | I do appreciate the discussion and disagreement. |
| <Roderick> | I've had my mtDNA done by another lab, and it came back "typical European Caucasian," but if it had come back "african" or "asian" or any other interesting place of origin, I'd be doing nothing but tracing that line. |
| <Wurts> | If I have two lines back to a Mohawk sachem (lower cheiftan) around 1630, does my DNA have duplicate strands identifying that relationship? |
| <Roderick> | No, it is possible but it depends. You might have duplicate strands from a single ethnic origin if they come come (one from the father and one from the mother. |
| <Roderick> | You might have both lines coming through your father, in which case you would not get duplications from that ancestor. The use of the term 'duplication' is good, because it is analogous to recessive mutations |
| <Sharon> | As to your mtdna coming back "typical Europian Caucasian," if I understood you correctly to my previous question, this would only be good for approx. 4 generations, so you may have African or Asian or what ever 5 or more generations back? |
| <Roderick> | I haven't made it clear. |
| <Roderick> | the mtDNA pattern I have will probably be identical to the pattern of ALL my umbilical ancestor females going back a few hundred years |
| <Roderick> | the 4 generation idea was what we look like, whether |
| <Roderick> | our hair is straight, blue eyes, long nose, etc. Those features wash out quickly in a few generations. But the genes in the mtDNA and Y chromosome are consistent over many many generations. |
| <Roderick> | May I give an interesting example. I have this 2nd hand, but in a lab that does mtDNA analysis, there was a woman who was from Yorkshire England, with red hair, blue eyes, fair skin, clearly a nordic type. But when they all did their mtDNA analyses, hers came back as Eastern Mediterranean or north african (something like that). The question is how? |
| <Roderick> | Her mtDNA told about her umbilical line ancestral origin, but the rest of her genes told about the VAST majority of her ancestors from Yorkshire. |
| <Roderick> | Possibly, since Yorkshire has always been a seaport with considerable commerce, an English ship returning a sailor brought back a bride and she had children there and their descendants lived there. Any other hypotheses? |
| <Sharon> | So, if you have native American heritage it would show no matter how many generations? |
| <Roderick> | She may have been dark complected, but in a few generations of intermarrying with Yorkshire families, that would be lost. but the mtDNA lived on! |
| <genealogyADM> | But the umbilical line characteristics can last longer than 3-4 generations can't they? |
| <genealogyADM> | You should see my kids blue eyes - with one shaped slightly differently than the other. I and my brother also have them (despite my father's brown eyes) |
| <genealogyADM> | My mother and grandmother and great-grandmother and gggrandmother also all have them |
| <genealogyADM> | Except I can't swear that my gggrandmother's were the same shade of blue since the picture is black and white |
| <Roderick> | Blue eyes in general tend to be recessive. Brown is dominant over blue usually. So if you are brown eyed |
| <Roderick> | and your husband is brown eyed, and some of your kids (or all of them) are blue eyed, then that means you are carrying the blue eyed gene. |
| <Roderick> | Professor CurtStern, one of science's early human geneticists, recalled a situation from his class. He had finished telling his class that brown eyed parents could have blue eyed children, but blue eyed children could not (rarely) have brown eyed children. The next day, one of his students came up to him and said, that she was an example of a brown eyed child from blue eyed parents, and she asked her parents about it. Then she was informed for the first time that she was adopted. |
| <genealogyADM> | Yes, I know blue tends to be recessive. That's why I find it so interesting that the same shade and shape of blue eyes have made it through at least 6 generations |
| <genealogyADM> | That's why I was wondering if mtDNA can carry back further than the 3-4 generations you were mentioning earlier |
| <Roderick> | Yes, the beauty of the mtDNA analysis is that it goes back possibly hundreds of generations. The various tribes thad DNA mentioned in her and her husband's analysis go back to separations of human populations over 50,000 years ago. |
| <genealogyADM> | So my mtDNA just happens to be very "dominant" in that my maternal French ancestry is dominating our physical characteristics over the German, English, Polish and Welsh coming in from other lines? |
| <Roderick> | No the mtDNA has no real physical characteristics associated. It is dominant in what it tells you about the molecular structure of your mtDNA only. It has almost nothing, NOTHING, to do with any physical characteristic (several genetic diseases excepted) that was what I meant to convey in my Yorkshire story. |
| <genealogyADM> | It's just so uncanny how much alike all of us look ;) I've always found it very interesting |
| <Roderick> | We haven't discussed tonight, the vast majority of our genes which are in the nucleus of our cells in our body. |
| <UnkHiram> | Roderick, First let me tell you I was the person that asked the "Sound Genealogy" Question, I didn't realize I had not signed on with my own name. Now I have a second Question for you. Its about the mtDNA thing. Would the Mother and her SISTER have the same mtDNA? |
| <Roderick> | Yes |
| <UnkHiram> | And as a direct result of that you would be unable to Prove which of the two was the actual Maternal line? |
| <Roderick> | the mother and her sister and her sister's children |
| <Roderick> | Absolutely correct. Many times we have seen examples where two parents die, and they are adopted, or perhaps adopted by the sister of the mother. the sister and her husband then raise them as their own. |
| <UnkHiram> | That is what I suspected |
| <Roderick> | So mtDNA analysis would definitely NOT prove |
| <Roderick> | would not shed evidence on which sister was the mother. |
| <Roderick> | Good question. |
| <genealogyADM> | Thanks for getting it cleared up for all of us Unk! |
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