Exploring Genealogy
with
Special
Guest
Thomas H. Roderick, PhD
Sponsored
by the
Genealogical Society of Pennsylvania
Transcript of Chat - 22 May, 2001
| <genealogyADM> | I would like to start off by introducing Jim Beidler, the Executive Director of the Genealogical Society of Pennsylvania |
| <genealogyADM> | They are the ones sponsoring this chat and we are all very grateful :-) |
| <genealogyADM> | It's a great society and one I would suggest you consider joining if you have PA ancestors! |
| <genealogyADM> | It's all yours, Jim! |
| <JMBeidler> | Thanks, Kimberly, especially for your technical expertise in making this possible. |
| <JMBeidler> | Virtual Lecture is indeed sponsored by GSP, this particular one with a grant from the Pennsylvania Humanities Council, the federal-state partner of the National Endowment for the Humanities. |
| <JMBeidler> | GSP has a Technology Special Interest group, which we can tell you about at the end, and without further ado ... |
| <JMBeidler> | I'd like to introduce Dr. Thomas H. Roderick |
| <JMBeidler> | He's the head of the Center for Human Genetics |
| <JMBeidler> | and an internationally known DNA scholar. |
| <JMBeidler> | He will answer our questions tonight on the relationships between genetics, genealogy, and our personal quests for identity. Take it away, Dr. Roderick ... |
| <Roderick> | Thank you, Jim. It's a pleasure to speak to this audience. I am grateful for the opportunity |
| <Roderick> | and with thanks to the Genealogical Society of Pennsylvania |
| <Roderick> | for this opportunity. |
| <Roderick> | Let's continue with questions? Anyone? |
| <genealogyADM> | Go ahead DNA! |
| <Roderick> | There may be a broad range of genealogical understanding, and this is very okay. Any level is perfectly good for discussion |
| <DNACousins> | Tom, I know you collected some pedigrees some years ago for possible mtDNA analysis. |
| <DNACousins> | Do you have any results, and are you still collecting pedigrees? |
| <Roderick> | I meant to say a broad range of genetic understanding. |
| <Roderick> | Almost 10 years ago we began collecting specific matrilineal |
| <Roderick> | lines called ""umbilical lines"" a term which has become somewhat fixed in American |
| <Roderick> | genealogical parlance. Our objective was to find |
| <Roderick> | long umbilical lines, fairly well documented, extending at least |
| <Roderick> | into the 1700s. Then we would inform each individual who sent in lines, whether a connection of their umbilical line |
| <Roderick> | matched with any umbilical ancestor of any other line. In each case the participants would have agreed |
| <Roderick> | ahead of time that they wished to be in touch with others and permitted our giving their name and address to anyone |
| <Roderick> | whose umbilical ancestress matched. One gentleman who was a mathematician |
| <Roderick> | thought that in about 150 submissions, (with many assumptions) |
| <Roderick> | that we would get a match. Indeed, I think it was No. 143 that matched another. At that time we had a collaborator, Dr. Mary-Claire King whose lab ran the mtDNA (that is mitochondrial DNA) of the two blood samples. And |
| <Roderick> | the DNA ladders matched perfectly with one exception which did not disprove the genealogical connection, but has |
| <Roderick> | interesting implications in itself. |
| <Roderick> | Now we have more than 500 umbilical lines submitted, and have several connections. But scientific labs such as that of Dr. King are not in the position to run |
| <Roderick> | DNA analyses for genealogists. Now we will continue to collect the umbilical genealogical information, and inform those whose lines match, and promote getting the mtDNA analysis done by private |
| <Roderick> | fee for service basis. There are a half dozen companies ""out there"" now who will do it. Our frustration at not having laboratory analysis available is nos met by the private sector! |
| <Roderick> | Does that answer the question? |
| <Sage> | How can we do DNA test on dead when we don' know where buried |
| <Roderick> | We really are not suggesting DNA analysis on dead individuals |
| <Sage> | If only live persons, how relate back to 1700 |
| <Roderick> | When your mtDNA matches mine, that means we have an ancestress in common in our umbilical lines, say within the last 10,000 years. And we know the mtDNA of all your umbilical line ancestors and mine up to that point. |
| <Roderick> | So we INFER the mtDNA pattern of the ancestors, without actually digging them up. |
| <Roderick> | Does that answer? |
| <Sage> | Would this be used to show families of same name but different oriigin related |
| <genealogyADM> | Tom - for projects like the one at BYU which collect pedigree charts for their database - how do you keep flawed pedigree charts from messing up the DNA database? |
| <Roderick> | In the umbilical line, we are dealing with our mother's mother's mother's etc. |
| <Sage> | why mother' line |
| <Roderick> | In each generation, the surname (under most systems) changes. Thus we would not be dealing with surname identity. |
| <Roderick> | The reason for mother's line is that it just happens that the mtDNA is only received from our mother. And she only could get it from her mother etc. |
| <Roderick> | It is quite different from all the other DNA inheritance where we get equal amounts from our mother and our father |
| <Roderick> | Does that answer? |
| <Sage> | Yes |
| <Sage> | thanks |
| <Roderick> | True, we are dealing with only a fraction of our ancestry |
| <Roderick> | but it is one of those fractions that WE CAN DEAL with in using DNA analysis in genealogy. |
| <Roderick> | To make a comment in parallel. The Y chromosome analysis can be done for the paternal line as well, again |
| <Roderick> | only a fraction of our ancestry, but one that we do have aDNA handle on |
| <Melissa> | I have reason to believe the slaveholder of my GGGGGrandmother was related. How can I tell? |
| <Roderick> | Is thia an ""umbilical"" ggggggrandmother? If so, and if you could find umbilical descendants, say around the plantation whee they lived, with the same mtDNA that would certainly be good evidence. Usually to get |
| <Roderick> | ggggggrandmothers, all umbilical, i.e. all mother to daughter, |
| <Roderick> | is very difficult, a real restriction. |
| <Roderick> | BUT if your gggggggrandmother was a slave, her mtDNA \ |
| <Melissa> | so you can only trace through females? |
| <Roderick> | being African in origin would be different from that of European origin. |
| <Melissa> | so you can only trace through females? |
| <Roderick> | For the mtDNA, yes, it only goes through an unbroken line of females |
| <Melissa> | Yes, her father was from Africa |
| <Roderick> | Yes, but there are other types of analyses where you can use nuclear DNA, but these are not as powerful. |
| <Roderick> | The problem with the father being from Africa is that he DID NOT pass his mtDNA to his daughter. So the mtDNA pattern would be that of the mother, who I assume was Caucasian??? |
| <Melissa> | no, but she is not first generation African. I don't have much information on her |
| <Roderick> | May I give an example from my own family? |
| <Roderick> | The mtDNA pattern of almost all Amerindians (native Americans) |
| <Roderick> | is of one of 4 types, clearly showing descent in most cases from Siberia or locations in the Far East. |
| <Roderick> | I am fairly sure my mother's father had a descent from a Mohawk lady, and could prove it if I could find an umbilical descendant from this lady. My grandfather had only a brother, BUT his mother had sisters with descendants in and around Lansing Michigan. So one of these days, I am going hunting in Lansing and find a relative, I hope, who has this unique umbilical descent from this presumed Mohawk Lady. If my grandfather were alive (he died in 1932) |
| <Roderick> | we could easily get a sample (a buccal smear sample) from the inside of the cheek, for the analysis. Blood is not not necessary. |
| <Roderick> | Also it is true, that his bones would yield the opportunity for analysis as well, but I am not suggesting I go do any digging, although my grandfather would have loved the whole idea. |
| <genealogyADM> | That's good to know Tom! So many people are afraid of blood tests because they are intrusive |
| <Roderick> | Yes, you'll find that the companies doing analysis today, do not require blood, only the inside the mouth cheek swab. You open the sterile envelope, make the swab, put it back into the envelope, seal it and mail it off. |
| <genealogyADM> | That's great! |
| <Melissa> | Good Luck!! Where can I find more information on your research and mtDNA? |
| <genealogyADM> | Melissa - you can find Dr. Roderick's lecture on genetics and genealogy as well as links to other genetic genealogy articles and research here: Genetic Genealogy |
| <BeccaRose> | I'm not sure I see how this helps today's genealogy community....seems like a lot of conjecture.....how much ""proof"" do you require? |
| <Roderick> | This is not an approach which will establish a genealogy, that is it will not tell you who your gggggrandmother is. It will tell you if there is reason to believe the genealogical work you have done is good, and also that of the person whom you are related to. |
| <Roderick> | If your mtDNA samples do NOT match, then there is almost complete proof that the lines you have established to show your relationship are wrong somewhere up or down the pedigree. |
| <Roderick> | In our mtDNA umbilical project we have hoped that people would send in good documentation along with their line of names and dates etc. |
| <BeccaRose> | what level of documentation have you required? |
| <Roderick> | But the match of mtDNA would be very positive evidence for a connection |
| <BeccaRose> | lineage documentation? |
| <Roderick> | Documentation: For each individual in the line, we have asked for full name, as much as possible, place and date of birth, marriage and to whom, and the sources that support this information, such |
| <Roderick> | as Braintree Vital Records, or Suffolk Co. Probate,, or cemetery stone records. |
| <BeccaRose> | those that could not provide all of that, were they still included in the study? |
| <Roderick> | Yes, we would accept it even if it were not fully documented. or if it was documented by a genealogy, but cite the published genealogy, some are better than others. |
| <BeccaRose> | oh my.....okay |
| <Roderick> | That isn't too daunting is it? |
| <BeccaRose> | just seems hard for me to rely too much on others research when the standards don't appear to be uniform.....too great a margin of error for my tastes |
| <BeccaRose> | but I guess to each his own |
| <Roderick> | I agree. It is best to follow strict standards of evidence in genealogical research as well as in any science. It is better to do that. We should write down WHY we know what we think we know. |
| <Roderick> | The umbilical line is a particular challenge. It changes surnames in each generation! In general, that is the shortest line that we have worked out. Simply because the surname is such a crutch in establishing a connection between generations. It's harder, so we leave it till the last. |
| <genealogyADM> | Ready Sharon? |
| <Sharon> | Would people of the same heritage but not necessarily same pedigree have similarities? Could this be used to prove Indian heritage for instance? |
| <Roderick> | It depends on how far removed you are from your Indian ancestor. I don't think racial differences between Caucasians and Asians can be found much beyond grandchildren of a mixed marriage. Between Blacks and the others, it is a bit farther because of color differences. but 4 generations of removal from another racial background pretty well washes it out. The mtDNA does not have any special feature that would promote similarities of individuals over many generations. |
| <Roderick> | Often we meet a 5th cousin and say how much we look like him or her, or our father did. It is only because we are looking for those similarities. But facial and other outward features wash away in 2 or 3 generations, usually. |
| <Roderick> | There is nothing special about our surname in providing similarities in face or other features. That is, I should look just as much like my father's father as my mother's father. |
| <Sharon> | Thank you Dr. Roderick |
| <Roderick> | May I ask if anyone is collecting medical genetic information on their family? Are you faced with ethical problems in getting the information and recording it? |
| <BeccaRose> | yes I am......but have no more of an 'ethics' issue in collecting it than with any other genealogical data......it's a matter of respect |
| <JMBeidler> | Tom, in your article on Genetics and Genealogy that you wrote for us, you noted how sensitive information on genetic defects can be found in a genealogical search and make the comment that you can tell other family members nothing about this. Is that your true recommendation or just the 'safest' way? It would seem that there would be a countervailing responsibility to inform people. |
| <Roderick> | You have hit on a very interesting controversy swirling in medical genetics |
| <Roderick> | 10 years ago one would have come down on the side of TOTAL confidentiality. But at an ethics meeting recently, I noted that several physicians and medical geneticists were advising that IF there were life threatening circumstances by NOT telling, then it was better to tell, and therefore break some confidentiality. What do you think about this? |
| <JMBeidler> | Well, I see the dilemma |
| <DNACousins> | Is there any good way to store DNA from older living relatives for tests a few years down the road? |
| <BeccaRose> | as with any other information I acquire from others in my research, I tell them ahead of time that it will be accessible to all......it then becomes something they must decide to share |
| <Roderick> | It can be an awful dilemma, because patients usually come to their physicians expecting strictest confidentiality. |
| <Roderick> | There are some labs, fee for service, who will freeze some tissue, perhaps blood for you for future generations. |
| <DNACousins> | I've seen advertisements for storing DNA on a card with a preservative. Would that be any good? |
| <Roderick> | I can't say. I don't know enough about it |
| <Roderick> | I know several authorities say that hair follicles, and not the usual snipped strands of hair are the only ones that contain DNA. But at a meeting recently (2 yrs ago) I saw a demonstration where the actual shaft of the hair contained DNA, the closer to the follicle the better. |
| <Roderick> | So, folks, save all those bits of hair that you find in your old family bibles. Try to identify them if you can. i.e. try to put a name to them. |
| <Sharon> | My son was born with a rare congenital disease, we do not know what side of family he inherited it from, could would tell this with dna? This would help future generations or possibly help explain why so many infant deaths in past generations |
| <Roderick> | Congenital simply means present at birth. It does not necessarily mean it is genetic. |
| <Roderick> | I gather there were no other members of the family (either side) afflicted with the same condition. That is a real problem in genetic counseling. It could be caused by an environmental insult in utero, |
| <Roderick> | i.e in development, or it could be a recessive disorder (i.e. inherited from both sides), or it could be a dominant, i.e. a parent had the problem but it was less expressed or simply not expressed obviously. |
| <Roderick> | Why do you think this particular problem is genetic? |
| <Sharon> | I was told it was inherited. Problem is a recent as my son's birth 30 yrs ago, the death rate was 80 percent before 6 weeks old |
| <Roderick> | It could be genetic, i.e. like Downs Syndrome, but it is |
| <Roderick> | not inherited. That is a new change in number of chromosomes of one kind. |
| <Sharon> | Hirshsprungs disease |
| <Roderick> | Well, you're sending me to my books. I'll have to look it up. |
| <Sharon> | also known as congenital megacolon |
| <Roderick> | I have at my desk (and it is also available free on the internet) a copy of McKusick's Mendelian Inheritance in Man, and it confirms that Hirschsprung's disease is a recessive. That means it take two copies of the problem gene in a person to express the disease. |
| <Roderick> | The child inherited it, one from one parent and one from the other, but in neither parent did the problem arise becvause only one defective gene was present. Such recessives could go generations before being expressed, so one shouldn't be surprised that there is no known other individual in the family with the disorder. |
| <Roderick> | It is not a good idea to do genetic counseling over the phone or on the web. |
| <Roderick> | You should probably inquire more thoroughly at a genetic counseling center, where your medical records could be scrutinized and you would have first hand advice. |
| <Sharon> | Thank you so much. |
| <Roderick> | I recommend anyone who has an interest in a genetic problem, access McKusick's catalog on line. |
| <genealogyADM> | McKusick's Mendelian Inheritance in Man |
| <DNACousins> | The BYU project is looking for markers on all the chromsomes, not just Y and mtDNA. It seems like it would be too hard to draw any conclusions because of all the shuffling. What do you think? |
| <Roderick> | The BYU project has long range goals. I understand that the immediate project will be exploratory in that they will use the pedigrees |
| <Wurts> | My Father has a pinky-toe bone from our immigrant (ca.1735) Wurts ancestor, acquired when his casket was relocated. Would mtDNA analysis of a fragment be of any particular value, or should I just plan on Y-Chromosone and Molecular DNA analysis to substantiate other individual's supposed connection to the immigrant? |
| <Roderick> | Sorry, I don't know what a Pinky Toe Bone is. They found that his small toe was deformed in some way when they dug up his remains? |
| <Wurts> | Small end toe bone on the foot. |
| <Roderick> | Do you mean doing an analysis on that toe?? |
Chat Transcript continued on next page...
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