Why do people still care about (distant) genealogy?

[Maciamo]

I guess that most of us have a family tree, and even if we did not make it ourselves, there is surely a relative in the family that spent considerable time (hundreds, if not thousands of hours) researching in archive rooms to go back as far as possible in time. There is often some kind of pride in some families to be able to claim that one descends from this or that famous ancestor who lived hundreds of years ago. Many will claim royal ancestry, and that typically ends up with the oldest surviving family trees in Europe, like those of the Carolingian and Merovingian dynasties. In fact, in countries where paper trails are particularly good, like in the UK, with a bit of effort almost anyone can find that they descend from Charlemagne and Clovis. Even if they can't, chances are that they do descend from them anyway, like most of us.

This in itself is not very bothering. Humans have sought to self-congratulate themselves and to seek pride in intangible and meaningless things like one's belief in an invented deity, or some potential descent from a medieval monarch about whom they usually don't know much really.

I was startled and rather disturbed to find out that the majority of people who order DNA tests do it for genealogical purposes, e.g. to complete their family tree or find distant cousins. I think that it's rather moronic (and I don't remember when is the last time I had to use that word before). I am going to justify myself, because obviously I cannot just say that something (or someone) is moronic without explaining why.

1) There is no point in claiming descent from ancestors who lived more than two centuries ago, because you may not have inherited any DNA from them

I suppose that part of the problem is that most people are inherently bad at maths. We inherited approximately 50% of our DNA from each parent, but because of DNA recombination we do not normally get just 25% from each grand-parent. It can be 23.642% or 26.87236% or whatever, but exactly 25% is almost unheard of. Therefor we do inherited more from some grand-parents than from others. This phenomenon amplifies at each additional generation. We may inherited about 18% of DNA from one great-grand-mother, but only 9% from another one. That's a two-to-one ratio, and only after three generations. Forget about text books that ridiculously explain that we inherit a fixed 12.5% from each great-grand-parent. That is misleading at best, especially when we apply the same logic to more distant generations.

After 7 generations, we do not inevitably inherited a mathematical 0.78125% of each ancestor's genome but that some ancestors contribute to more than 2% and others to 0%. And that's barely after 7 generations. People who pride themselves in descending from Charlemagne do not seem to understand that the man lived over 40 generations from us. In other words, even if his genetic contribution was not eliminated by recombinaisons somewhere along those 40 generations, the amount contributed would be less than 0.0000000001% of the genome.

All this to say that single ancestors on a family tree do not contribute anything meaningful to one's genome after a few generations. The only ancestor that keeps contributing the same 1% of DNA generation after generation, even after 1000 or 2000 years if the one on the patrilineal line for men. But what does that mean to share a Y chromosome? I have several paternal uncles and cousins sharing my Y chromosome and they couldn't be more different from me in every regard. We literally don't share anything in common.


2) Third and more distant cousins do not share any meaningful amount of DNA with you

Through of the laws of genetic recombination, siblings statistically share 50% of their genome, but in practice may share very different percentages, maybe between 40 and 60%. So your sibling's children may inherit about 20 to 30% of your DNA. According to 23andMe (based on observed customer data), first cousins share 7.31% - 13.8%, 2nd cousins 2.85% - 5.04%, and 3rd cousins a paltry 0.2% - 2%. In other words two men who share the same Y-chromosome, but separate by dozens of generations and with no known genealogical ties, may share more DNA through their Y-chromosome alone than two proven third cousins. That's just the way it is. Third cousins are not better than strangers in terms of genetic similarity. Anybody who believes that they are finding "blood relatives" when finding third or fourth cousins through DNA testing companies are badly deluded.

Even if they were to find first or second cousins that they didn't know about (I wonder how that's possible unless one was adopted), that still wouldn't guarantee that you share anything in common, be it for tastes, sensitivities, interests, way of thinking or whatever else matters in a relationship with another human being. If you are looking for people like you, join interest groups or online forums like this one. Don't waste your time imagining that because you share a few percent of DNA you will be compatible in any way. Just look at the number of siblings who can't stand each others, or at least don't have anything in common.

Conclusion

Attaching importance to distant ancestors or distant cousins in one's genealogy is almost as irrational and meaningless as astrology. People purchasing DNA tests for that sole purpose are wasting their money.


It's very sad because DNA test are so revolutionary and fantastic in so many ways. Everybody should have their genome sequenced, if only to know about their health risk. I absolutely cannot understand why anybody would not want to know who they are, or fear to find about disease risks (the logic is that if you don't know you can't prevent it and therefore you are likely to die from it). Why are people wasting their time with genetic genealogy and finding distant relatives?

For anybody interested in (pre)history and/or anthropology (e.g. human variations across ethnic groups, but also variations in time, across historical periods), DNA tests are a total boon. We could never hope for such a wonderful tool to solve many of history's secrets. It's ironic that Europeans, who care much more about history than almost anyone else, order less DNA tests than Americans. It's even more ironic that among Europeans the French may be the most obsessed about history, and yet it is the only country in he world where DNA tests are prohibited by law (what terrible secrets may they be hiding?).

 

[Sennevini]

I think you are right, genetically spoken.
I thought about the following myself: as West-European, I can establish some lines to the medieval nobility, which comprises about 25-40 generations ago. Someone like Charlemagne would pop up 40 generations ago, but would appear many times, due to intermarriages. If the ca. 1.000.000.000.000 ancestor "slots" about 40 generations ago would be filled by about 10 million people living ca. 700-800 (a vague estimate), someone 40 generations ago would be represented ca. 100.000 times. Initially I thought that would mean they, genetically, would be pulled to the present, if you know what I mean. However, many of those nobility lines crossed over around 30 generations ago, which is after Charlemagne's DNA would have been diminished a lot.

But still, the people from the middle ages may have genetically disappeared, or meaninglessly recombined, we must be their descendants. Being Dutch, I know I must have a lot of medieval Frankish blood, even if 99,9999% can't be traced back due to lack of documentation. Is it fair to say that the people individually doesn't mean much, but descent from the group does?

There is another reason of course besides genetics. It's cultural. It creates a feeling between the present and the past, and a feeling of belonging somewhere, (which might be stronger in Europe than America). I know of a family which already in 1550 delivered protestant preachers. Descendants in 1900 were still preachers.

 

[Angela]

I suppose for some it's as you say: it's looking for reflected glory. Perhaps for some it's a way of connecting with the history of their country or area or ethnicity. Perhaps there are more intimate, familial reasons.

Personally, I'm immune if not hostile to the whole idea, if for no other reason than I was born and partially raised in one of the most anti-monarchist, anti-nobility areas of Italy, a hot bed of anarchism and socialism/communism. We sort of imbibe hatred of our local robber-barons, the Malatesta, with our mother's milk. Like a lot of people I didn't do my family tree, although I was pressured to fill in some of the gaps, and finding that name scattered about in my mother's line was not welcome. However, it's probably just retainers who took the name, and even if some are actually descended from that family, as you say, the likelihood I inherited any DNA from them is remote to nil. The only very distant ancestor whom I find rather intriguing is a supposed "pirate" who was based around Venezia and supposedly preyed on Ottoman ships. He played the game incorrectly, annoying the authorities, and had to hotfoot it up to the refuge of the mountains. Now him I would have liked to have met, but not because any of his genes are necessarily in me.

I'm very attached to the people of my ancestral areas, and identify with them and their culture, but I'm really not interested in any of the people in my tree other than the ones I knew or at least heard a great deal about who are not too far removed in time.

As for "cousins", I have twenty-four first cousins on my father's side, some of whom I love dearly, and some of whom I can't stand. I don't need any more. For that matter, everybody in my ancestral villages is no doubt a "cousin" of some sort or another. In my experience, the people I've adored are sometimes my "blood" relatives, and often they're not. It's the heart that rules.

I do think that some of this interest in finding "cousins" is to answer sometimes emotional questions having to do with illegitimacy, abandonment, etc. I wish these people only the best, although not every such quest turns out happily. In other cases, this search is conducted by Americans who, because of the looser family ties and great mobility, as well as the high level of "ethnic" admixture, have no "ancestral" area with which to identify. I understand that they might want to close that gap.

 

[sparkey]

Maciamo, I think you're wrongly assuming that genealogists (myself included) are primarily interested in genetic inheritance. In my experience, most people are using DNA as a tool, not as a goal; that is, they're not trying to use their family tree to determine their DNA inheritance, but rather they're using DNA as a tool to make sure that their family tree is correct. It may be "moronic" to do the former, but it's completely understandable to do the latter.

Are family trees meaningful beyond the point of mathematically meaningful DNA relationships? I think they are. For one, (good) genealogists don't focus on only single individuals from certain time periods. Uncovering a single ancestor who lived in the 1600s may tell you little about your family in the 1600s, but uncovering a large number will give you a good sample of what sorts of people you descend from who lived in that time period, even if you don't have 100% coverage. It also can give you a sense of personal connection to historical events and people. I find that it can often be more engaging to imagine historical events through the lens of "What were my ancestors doing during this?" It's also important, I think, to remember that most people don't have ancestors who moved around much, and oftentimes descend multiple times from an ancestor they can trace so far back. I know that in the side of my family with the most coverage in the 17th and 18th century (my Cornish side), I see frequent repeats of individual ancestors.

Tracing truly ancient royal genealogy is less useful in my opinion, but I can understand why it happens. A rule of thumb for British genealogy is that you can get back to the 1800s for a poor family with a common surname (civil registration), the 1600s or 1700s for a poor family with an uncommon surname (parish registers and wills), the 1400s for a long-seated gentry family with no royal connections (herald's visitations), and back to Charlemagne and beyond for a noble family with royal connections (royal pedigrees). Each is increasingly uncommon; I have yet to find a 100% confirmed case of the last case in my family tree despite several instances of the next-to-last. (My wife can be easily connected to the last case due to reasonably recent descent from the Courtenays of Trethurffe, however.) But for many people, the most interesting time periods are the ones that you could only possibly get to with the last case. So they latch onto a small number of lineages in their tree that give them that, and inevitably, it leads to royals.

I've had a lot of successes with doing genealogy via DNA, enough that I would definitely recommend it to others. I've confirmed that my paternal lineage is from Switzerland; that my mother's maiden line is from Scotland; and that I'm definitely related to Thomas Sumter. These sorts of cool anecdotes keep people interested in genealogy, genetic and otherwise. It's not entirely about DNA percentages, it's about relationship, history, and storytelling.

 

[Maciamo]

I suppose for some it's as you say: it's looking for reflected glory. Perhaps for some it's a way of connecting with the history of their country or area or ethnicity. Perhaps there are more intimate, familial reasons.

Personally, I'm immune if not hostile to the whole idea, if for no other reason than I was born and partially raised in one of the most anti-monarchist, anti-nobility areas of Italy, a hot bed of anarchism and socialism/communism. We sort of imbibe hatred of our local robber-barons, the Malatesta, with our mother's milk. Like a lot of people I didn't do my family tree, although I was pressured to fill in some of the gaps, and finding that name scattered about in my mother's line was not welcome. However, it's probably just retainers who took the name, and even if some are actually descended from that family, as you say, the likelihood I inherited any DNA from them is remote to nil. The only very distant ancestor whom I find rather intriguing is a supposed "pirate" who was based around Venezia and supposedly preyed on Ottoman ships. He played the game incorrectly, annoying the authorities, and had to hotfoot it up to the refuge of the mountains. Now him I would have liked to have met, but not because any of his genes are necessarily in me.

I'm very attached to the people of my ancestral areas, and identify with them and their culture, but I'm really not interested in any of the people in my tree other than the ones I knew or at least heard a great deal about who are not too far removed in time.

As for "cousins", I have twenty-four first cousins on my father's side, some of whom I love dearly, and some of whom I can't stand. I don't need any more. For that matter, everybody in my ancestral villages is no doubt a "cousin" of some sort or another. In my experience, the people I've adored are sometimes my "blood" relatives, and often they're not. It's the heart that rules.

I also checked my family tree by curiosity. Going back a few centuries though, genealogy turns into local history. That can be interesting too, but it doesn't matter who were our "paper ancestors" at the time as we would have inherited only a teeny tiny fraction of their DNA, if any at all.

I have as many first cousins as you, and like you, almost all my ancestors come from the same region (30 km radius more or less). I sometimes cringe at the idea that indeed most of the people in my rural ancestral region are distant "cousins", although I know it doesn't mean anything.

I do think that some of this interest in finding "cousins" is to answer sometimes emotional questions having to do with illegitimacy, abandonment, etc. I wish these people only the best, although not every such quest turns out happily. In other cases, this search is conducted by Americans who, because of the looser family ties and great mobility, as well as the high level of "ethnic" admixture, have no "ancestral" area with which to identify. I understand that they might want to close that gap.

Perhaps some people order these tests because of illegitimacy or abandonment issues. But they should only represent a small fraction of society. Just take the case of Ancestry.com, which specialises in genetic genealogy. They do not provide any medical data like 23andMe, and their test is not suitable for historical population genetics either (they don't test mtDNA and their Y-DNA data is extremely basic). Yet some 800,000 people have ordered their test. Are they all emotionally desperate people looking to reconnect with lost relatives? I hope not.

As for the Americans with mixed ethnic backgrounds, especially those whose ancestors have been there for several centuries and who have lost touch with their roots, I can understand that they might want to know what genetic blend they have inherited. But that's population genetics (comparing the DNA of modern or historical populations), not genetic genealogy (defined as the combined use of traditional genealogy with DNA testing to infer relationships between individuals). If they are looking to find a specific ancestral area, they won't find one if they have ancestors from many different countries. It's unfortunate that companies like Ancestry.com and FTDNA are deceiving so many customers by having them believe that their "ethnic mix" is remotely accurate. It is surely good enough to tell people approximately what percentage of European, Amerindian, African, East Asian or South Asian ancestry they have. But within Europe the accuracy is still abysmal from what I have seen, and most White Americans are interested in just that.

 

[Maciamo]

Maciamo, I think you're wrongly assuming that genealogists (myself included) are primarily interested in genetic inheritance. In my experience, most people are using DNA as a tool, not as a goal; that is, they're not trying to use their family tree to determine their DNA inheritance, but rather they're using DNA as a tool to make sure that their family tree is correct. It may be "moronic" to do the former, but it's completely understandable to do the latter.

I was referring to genealogists using DNA as a tool to confirm family trees actually. That seems like an awful lot of trouble and money spent just to confirm that you share a great-great-great-great-great-grand-father with a very distant cousin, who is essentially a stranger. What do you get from it?

Are family trees meaningful beyond the point of mathematically meaningful DNA relationships? I think they are. For one, (good) genealogists don't focus on only single individuals from certain time periods. Uncovering a single ancestor who lived in the 1600s may tell you little about your family in the 1600s, but uncovering a large number will give you a good sample of what sorts of people you descend from who lived in that time period, even if you don't have 100% coverage. It also can give you a sense of personal connection to historical events and people.

I find that it can often be more engaging to imagine historical events through the lens of "What were my ancestors doing during this?"

But that's an illusion because you may not have inherited any DNA from a 17th century line of ancestors. Maybe after 5 generations converged into one individual in the 18th century, that ancestor's DNA got quickly diluted. It could have gone like 50%, 23%, 9%, 3%, 0.4%, 0.02%, 0%, and bam in only 7 generations all their DNA is gone to the profit of other ancestors! It's a bit 'winner takes it all' in DNA inheritance. There is no fairness. Otherwise we would inherit exactly half the DNA of each ancestor at every generation. But it doesn't work like that.

Then there is always the relatively high possibility (by some estimates 3 to 5% of chance per generation) that a given female ancestor cuckolded her husband, or that a child was secretly adopted. Short of digging up our ancestor's graves and testing their DNA, we will never know. If a 'non-paternity event' took place only a few generations ago (people are typically afraid to look too near), then a who branch of our family tree could be completely wrong. I guess you will tell me that is exactly why people like to confirm their genealogy with DNA tests. But we can only do that for Y-DNA lines, and it would be quite costly to test even the 64 lines of the last 7 generations, and surely close to impossible to find enough living relatives to to triangulate and confirm each branch (le alone convince them to take the test or pay for them). That's just crazy. And all this to confirm the name of an ancestor from whom you still might not have inherited any DNA after 7 generations 'see above).

It's also important, I think, to remember that most people don't have ancestors who moved around much, and oftentimes descend multiple times from an ancestor they can trace so far back. I know that in the side of my family with the most coverage in the 17th and 18th century (my Cornish side), I see frequent repeats of individual ancestors.

I guess it's quite different for Americans who had more "mobile" ancestors. Europeans usually have most of their ancestors from the same region, so it's not hard to relate to local history and to imagine what one's ancestors lives were like.

Tracing truly ancient royal genealogy is less useful in my opinion, but I can understand why it happens. A rule of thumb for British genealogy is that you can get back to the 1800s for a poor family with a common surname (civil registration), the 1600s or 1700s for a poor family with an uncommon surname (parish registers and wills), the 1400s for a long-seated gentry family with no royal connections (herald's visitations), and back to Charlemagne and beyond for a noble family with royal connections (royal pedigrees). Each is increasingly uncommon; I have yet to find a 100% confirmed case of the last case in my family tree despite several instances of the next-to-last. (My wife can be easily connected to the last case due to reasonably recent descent from the Courtenays of Trethurffe, however.)

Yes, but you can never be sure. Not only can their be mistakes in the paper genealogy, the cumulative chances of non-paternity events are getting so high after 20 or 30 generations that it becomes meaningless. We have seen with Richard III's DNA vs modern descendants of Plantagenets that even royals aren't immune to it, despite all the precautions taken. And even if it is correct, it would still be genetically meaningless.

I've had a lot of successes with doing genealogy via DNA, enough that I would definitely recommend it to others. I've confirmed that my paternal lineage is from Switzerland; that my mother's maiden line is from Scotland; and that I'm definitely related to Thomas Sumter. These sorts of cool anecdotes keep people interested in genealogy, genetic and otherwise. It's not entirely about DNA percentages, it's about relationship, history, and storytelling.

It's nice that you had successes and I am happy for you if you could find some sense of connection out of it. By I still don't understand what makes you more related to Thomas Sumter than me of anyone else if you can't be sure that you inherited any DNA segment in common? I think it would be much more meaningful to sequence the whole genomes of lots of historical people (say 10,000 of them for a start), then have people compare their degree of genetic similarity with them. I would be much more willing to spend my money to know what famous people in history were genetically similar to me than to confirm my paper genealogy. We could imagine that such companies would provide a ranking of genetic similarities, and even provide the possibility to fine tune the search by genes linked to particular traits or abilities. That would be fun.

 

[Angela]

I see these things the same way that you do, Maciamo, particularly when you said that if most of your ancestors come from a certain circumscribed area (or two areas, in my case), after a certain period of time it's just about local history and local genetics. That's what interests me.

I just have no interest in an ancestor from 300 years ago whose specific dna I probably don't carry, other than in so far as that ancestor is emblematic of what I consider "my people", and their history.

You're also correct about illegitimacy and secret adoption rates. The percentage per generation is low, but after 20, 30 generations? For people like us with all our ancestors from specific areas during that time period it doesn't really matter, though. The genes are all thoroughly scrambled, and everyone is related to one degree or another.

That's why my interest is in my "ancestral areas", not my family tree per se.

You're also correct about the advertising making promises which can't be fulfilled. Ancestry, in particular, are rather misleading, in my opinion. There's two ads playing constantly: in one the guy is trading in his lederhosen for a kilt, and in the other the man claims he's discovered he's not mostly Italian, he's mostly eastern European. In the latter case, I have no idea what that could mean. Was one of the ancestors Croatian? Is it just that Balkan is showing up? It's a mess.

Actually, Americans would be better off doing extensive family trees than pinning their hopes on this kind of analysis. Doing a family tree is a lot more work, however, and lot's of people like an easy alternative. Unfortunately, it's not accurate.

 

[Northener]

I see these things the same way that you do, Maciamo, particularly when you said that if most of your ancestors come from a certain circumscribed area (or two areas, in my case), after a certain period of time it's just about local history and local genetics. That's what interests me.

I just have no interest in an ancestor from 300 years ago whose specific dna I probably don't carry, other than in so far as that ancestor is emblematic of what I consider "my people", and their history.

You're also correct about illegitimacy and secret adoption rates. The percentage per generation is low, but after 20, 30 generations? For people like us with all our ancestors from specific areas during that time period it doesn't really matter, though. The genes are all thoroughly scrambled, and everyone is related to one degree or another.

That's why my interest is in my "ancestral areas", not my family tree per se.

You're also correct about the advertising making promises which can't be fulfilled. Ancestry, in particular, are rather misleading, in my opinion. There's two ads playing constantly: in one the guy is trading in his lederhosen for a kilt, and in the other the man claims he's discovered he's not mostly Italian, he's mostly eastern European. In the latter case, I have no idea what that could mean. Was one of the ancestors Croatian? Is it just that Balkan is showing up? It's a mess.

Actually, Americans would be better off doing extensive family trees than pinning their hopes on this kind of analysis. Doing a family tree is a lot more work, however, and lot's of people like an easy alternative. Unfortunately, it's not accurate.

RIght! I agree especially with interest for ancestral area's and heritage. And most of of all: how are the genetic "mastrushka" of these area's are constructed. What is the migration history? What are the linkages with a other area's? Why do they resemble or differ?

That leads to a personal drive for me with on the one hand a outmost NW European aDNA and on the other hand a Y-DNA from Egypt! How come?

Just one correction Maciamo and Angela, according to geneticist Maarten Larmuseau the illegitimate percentage is only 1%. He has done much research about this.....


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[Maciamo]

Just one correction Maciamo and Angela, according to geneticist Maarten Larmuseau the illegitimate percentage is only 1%. He has done much research about this.....

I have seen various studies on this. It varies a lot depending on the country, social class, and historical period. As a rule of thumb, poorer and less educated people tend to have a higher rate of cuckoldery for several reasons. Men have less to lose if they are unemployed and no no money to provide to the children anyway. Men at the bottom of the social order tend to be less desirable genetic material, and therefore women have more to gain from cheating with a more intelligent, healthier or better looking man. Local culture is also important. In 18th century France, libertinage was all the rage among the aristocracy and there must have been a fairly high percentage of cuckolded husbands (although cuckolded by other aristocrats, so it stays in the extended family).

Even if 1% is a good average, after 6 or 7 generations there is a very high chance that at least one of your presumed ancestors (and all his ascendants on the tree) isn't your biological ancestor.

 

[Sile]

There should be a poll done on why people do DNA testing, and IMO the medical side would be on the lower end of the % compared to finding out ones true paternal/maternal side


In Australia they do DNA testing for immigration purposes

A DNA immigration test is a paternity, maternity or kinship test conducted at the request of the Department of Immigration and Border Protection of Australia and performed by a NATA Accredited Laboratory such as DNA Solutions. NATA Accredited DNA Solutions Laboratory specialises in DNA Tests for Immigration purposes accepted and recommended by the Australian Department of Immigration and Border Protection. We are a leading DNA testing company that holds ISO Accreditation 17025 granted by the National Association of Testing Authorities (NATA). We can organise Immigration Paternity & Relationship DNA tests as requested by the Australian Department of Immigration and Border Protection. If you are applying for an Australian Visa, DNA Solutions is your fastest and most affordable option. We have been working worldwide with Embassies, Consulates and Migration Agents for the past 10 years ensuring the best outcome for our clients.


They are ahead of Europe in this respect, especially since the germans have found out so far that over 1500 syrian refugees with children are not the children of the person even though they declare it.

You will hear in the near future in Australia, all single mothers children will be tested so the claim for child care by the mother is correctly targeting the father.


I did the tests only for my familytree and trying to find its origins. I have no interest in the medical side.


Since my father passed away 6 months ago , I declared , as executor of the will that any person contesting of the will must be DNA tested . In Australia all wills are confirmed by only the supreme court by issuing a Grant of Probate after 90 days. This is what most people do in Australia now.

 

[Sennevini]

It is useful though in my opinion to go further back than 7 generations, because of historical events influencing the genome.
An example: I have some 18th century ancestors from the Hollandic cities. Did they give me Hollandic genes? Well, they did, but
in many cases, I find some of them being almost half Flemish/Antwerpian, due to the immigration around 1600, or having a lot of
Huguenot ancestry. I feel like I need to push back further to not mistake a half-Flemish or half-French ancestor for being a Hollandic one.

 

[sparkey]

I was referring to genealogists using DNA as a tool to confirm family trees actually. That seems like an awful lot of trouble and money spent just to confirm that you share a great-great-great-great-great-grand-father with a very distant cousin, who is essentially a stranger. What do you get from it?

My end goal is usually history writing through the lens of my family, it has never been to connect to distant cousins. It can be nice to meet distant cousins who share research interests on the same distant ancestors, but not really in a different way than how it is nice to meet anybody with the same research interests.

But that's an illusion because you may not have inherited any DNA from a 17th century line of ancestors. Maybe after 5 generations converged into one individual in the 18th century, that ancestor's DNA got quickly diluted. It could have gone like 50%, 23%, 9%, 3%, 0.4%, 0.02%, 0%, and bam in only 7 generations all their DNA is gone to the profit of other ancestors! It's a bit 'winner takes it all' in DNA inheritance. There is no fairness. Otherwise we would inherit exactly half the DNA of each ancestor at every generation. But it doesn't work like that.

Then there is always the relatively high possibility (by some estimates 3 to 5% of chance per generation) that a given female ancestor cuckolded her husband, or that a child was secretly adopted. Short of digging up our ancestor's graves and testing their DNA, we will never know. If a 'non-paternity event' took place only a few generations ago (people are typically afraid to look too near), then a who branch of our family tree could be completely wrong. I guess you will tell me that is exactly why people like to confirm their genealogy with DNA tests. But we can only do that for Y-DNA lines, and it would be quite costly to test even the 64 lines of the last 7 generations, and surely close to impossible to find enough living relatives to to triangulate and confirm each branch (le alone convince them to take the test or pay for them). That's just crazy. And all this to confirm the name of an ancestor from whom you still might not have inherited any DNA after 7 generations 'see above).

You're still thinking here in terms of genetic inheritance being the primary thing of interest when researching relationships, but not many people think that way. Sure, genetic inheritance is one of the most important and profound part of family tree relationships, and I personally have an unusually high interest in it, but there are many other interesting aspects as well. The way that folkways tend to be passed down from generation to generation is almost always of interest as well (although I can understand how it might be of more interest to people like Americans who are displaced from the origin of their folkways). Why, for example, have I spent a little bit of time researching my mother's stepmother's family? I knew they're not blood relatives to begin with, but there's a definite sense that I received a bit of her family history via transmission of folkways, even without transmission of genetics. That's of interest to me, as are the stories I uncovered and was able to tell to her--as again, genealogy is often a storytelling mechanism.

I guess it's quite different for Americans who had more "mobile" ancestors. Europeans usually have most of their ancestors from the same region, so it's not hard to relate to local history and to imagine what one's ancestors lives were like.

This might be true, and I agree that a European who was born in the same locale as their entire family history would quickly find that genealogy is just local history. However, I will say that some of the best research I've seen done on one-place studies have been by Europeans who have a lot of family history in a particular place, but don't live there any longer. American family history can be almost too mobile, with many Americans of colonial family history falling into the trap of not performing any research on locales because there are too many. A lot of my genealogical research has been done finding patterns and hotspots, and then learning about the related local and migration histories associated with them, rather than just finding new names.

It's nice that you had successes and I am happy for you if you could find some sense of connection out of it. By I still don't understand what makes you more related to Thomas Sumter than me of anyone else if you can't be sure that you inherited any DNA segment in common? I think it would be much more meaningful to sequence the whole genomes of lots of historical people (say 10,000 of them for a start), then have people compare their degree of genetic similarity with them. I would be much more willing to spend my money to know what famous people in history were genetically similar to me than to confirm my paper genealogy. We could imagine that such companies would provide a ranking of genetic similarities, and even provide the possibility to fine tune the search by genes linked to particular traits or abilities. That would be fun.

Is it too obvious to answer that I'm more related to Thomas Sumter because he's apparently my 6th-great granduncle, but not yours? I get what you're saying that it's a realistic possibility that I share 0% DNA with him, but it's also significantly more likely that I share DNA with him than you do. And even if the answer is ultimately that I share 0% DNA with him, it's still interesting to claim the relationship, because even if he's just a relative of a relative who helped raise an ancestor of mine, that's still a pretty interesting story.

 

[Angela]

That's the best explanation I've ever read about why people do genealogy.

 

[LeBrok]

My end goal is usually history writing through the lens of my family, it has never been to connect to distant cousins. It can be nice to meet distant cousins who share research interests on the same distant ancestors, but not really in a different way than how it is nice to meet anybody with the same research interests.



You're still thinking here in terms of genetic inheritance being the primary thing of interest when researching relationships, but not many people think that way. Sure, genetic inheritance is one of the most important and profound part of family tree relationships, and I personally have an unusually high interest in it, but there are many other interesting aspects as well. The way that folkways tend to be passed down from generation to generation is almost always of interest as well (although I can understand how it might be of more interest to people like Americans who are displaced from the origin of their folkways). Why, for example, have I spent a little bit of time researching my mother's stepmother's family? I knew they're not blood relatives to begin with, but there's a definite sense that I received a bit of her family history via transmission of folkways, even without transmission of genetics. That's of interest to me, as are the stories I uncovered and was able to tell to her--as again, genealogy is often a storytelling mechanism.



This might be true, and I agree that a European who was born in the same locale as their entire family history would quickly find that genealogy is just local history. However, I will say that some of the best research I've seen done on one-place studies have been by Europeans who have a lot of family history in a particular place, but don't live there any longer. American family history can be almost too mobile, with many Americans of colonial family history falling into the trap of not performing any research on locales because there are too many. A lot of my genealogical research has been done finding patterns and hotspots, and then learning about the related local and migration histories associated with them, rather than just finding new names.



Is it too obvious to answer that I'm more related to Thomas Sumter because he's apparently my 6th-great granduncle, but not yours? I get what you're saying that it's a realistic possibility that I share 0% DNA with him, but it's also significantly more likely that I share DNA with him than you do. And even if the answer is ultimately that I share 0% DNA with him, it's still interesting to claim the relationship, because even if he's just a relative of a relative who helped raise an ancestor of mine, that's still a pretty interesting story.

Hah, the romanticism. Mine is a bit different. I don't care too much for close cousins who I never met, or many great grandfathers to research, but love reading stories about extraordinary people who did a lot for humankind. Even though my genetic connection with them is only through being a human.

 

[Valerius]

What about these admixtures from FTDNA (MyOrigins), a genetic material from different places. Do they have some effect or it's just "deadwood"? If some far-distant admixture was added to your local gene-pool, let say 2000 years ago and we are still inheriting this admixture despite recombination then isn't it still important?

 

[Northener]

What about these admixtures from FTDNA (MyOrigins), a genetic material from different places. Do they have some effect or it's just "deadwood"? If some far-distant admixture was added to your local gene-pool, let say 2000 years ago and we are still inheriting this admixture despite recombination then isn't it still important?

Of course it detects interaction and connections (in the past) between regions....


Sent from my iPad using Eupedia Forum

 

[leperrine]

I got into studying my genetic origins to learn more about my ancestors and history. Being an American, I knew very little about my ancestors in Europe and why they left. It's given me greater compassion for my European kinsmen.

 

[Twilight]

A Charlamane decent is excessive, I hope that the person is claiming such a decent via a clan and not via mathematics. Anyways, Guilty as charged for claiming distant decent. However, my claim to distant decent ONLY comes in the form of Scottish clan tradition and not via mathematics. The clans that can be attributed to me via my Maternal Grandmother's Father's side are MacDonald of Sleat, MacVey; Clan Sept of Maclean, MacLey, Lindsay, Baillie, Ralston and Boyd. There is also Clan Neely via my Maternal Grandfather's side. Mac means "Son of" and O' means "Decent" in Celtic. Idk about you but there is something rather alluring and rather mystical about claiming your decent; either from an ancient civilization or the like, like the Irish claiming decent from the celts for example.


Personally the reason why I got interested in Genetic Geneology was for one, I thought it would be interesting to learn about my health and read up on any scientific discoveries relating to my Autism. Another reason for getting into genetics was because ever since I was little, the only books that I have really been able to read and memorize were non-Fiction history books and historical fiction. As a result, history has really helped me via school because it helped me on my comprehension. After graduating from school and settling in the workforce, Genetic Geneology has given me the chance to learn other parts of history that I may have overlooked and read about them; before I got tested I had no Idea that the Slavic Wends even existed in Germany for example.


Anyways, here are a list of Clan names. https://en.m.wikipedia.org/wiki/List_of_Scottish_clans



https://en.m.wikipedia.org/wiki/Irish_name

 

[Rethel]

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[Avicenna]

Bad at maths

... I suppose that part of the problem is that most people are inherently bad at maths. We inherited approximately 50% of our DNA from each parent, but because of DNA recombination we do not normally get just 25% from each grand-parent. It can be 23.642% or 26.87236% or whatever, but exactly 25% is almost unheard of. Therefor we do inherited more from some grand-parents than from others. This phenomenon amplifies at each additional generation. We may inherited about 18% of DNA from one great-grand-mother, but only 9% from another one. That's a two-to-one ratio, and only after three generations. Forget about text books that ridiculously explain that we inherit a fixed 12.5% from each great-grand-parent. That is misleading at best, especially when we apply the same logic to more distant generations.

After 7 generations, we do not inevitably inherited a mathematical 0.78125% of each ancestor's genome but that some ancestors contribute to more than 2% and others to 0%. And that's barely after 7 generations. People who pride themselves in descending from Charlemagne do not seem to understand that the man lived over 40 generations from us. In other words, even if his genetic contribution was not eliminated by recombinaisons somewhere along those 40 generations, the amount contributed would be less than 0.0000000001% of the genome.

All this to say that single ancestors on a family tree do not contribute anything meaningful to one's genome after a few generations. The only ancestor that keeps contributing the same 1% of DNA generation after generation, even after 1000 or 2000 years if the one on the patrilineal line for men. But what does that mean to share a Y chromosome? I have several paternal uncles and cousins sharing my Y chromosome and they couldn't be more different from me in every regard. We literally don't share anything in common.

...
Through of the laws of genetic recombination, siblings statistically share 50% of their genome, but in practice may share very different percentages, maybe between 40 and 60%. So your sibling's children may inherit about 20 to 30% of your DNA. According to 23andMe (based on observed customer data), first cousins share 7.31% - 13.8%, 2nd cousins 2.85% - 5.04%, and 3rd cousins a paltry 0.2% - 2%. In other words two men who share the same Y-chromosome, but separate by dozens of generations and with no known genealogical ties, may share more DNA through their Y-chromosome alone than two proven third cousins. That's just the way it is. Third cousins are not better than strangers in terms of genetic similarity. Anybody who believes that they are finding "blood relatives" when finding third or fourth cousins through DNA testing companies are badly deluded.

...

Thank you, as usually, for your interesting thoughts, which are true in many ways.

But: if you recall the total number of genes for an average today human is about 22,500, and the number of base pairs on that genes is over 3 billion (3,000,000,000), or altogether 6 billion genetic informations, then also a little percentage of identical information might be of interest. In your examples: after 7 generations you share roundabout 225 genes with your 1%-forefather (or foremother), or 30 million base pairs=60 million genetic informations. It is kind of a wonder, how rich the genetic material of one single human is anyway, and if it is the gentic information for how you move your hands, your lips, your voice, certain thought patterns, there may be an important identity with one of your ancestors in the year 1700. And I personally like the romantic idea behind it very much too. You sure heard of the concept of synchronicity by Carl Gustav Jung (one of my avatars followers long time 'go).

And, take it easy: your 40-generation-ancestor Charlemagne (I bet you are also one of his noble descendents ) only has 3 base pairs in common with you (if I counted it right), or 6 little informations. So don't worry that you will become as despotic as him. Many greetings Avicenna