- 2 days ago
Finding Your Roots lead genetic genealogist CeCe Moore joins WIRED to answer the internet’s burning questions about genealogy. Can a person’s innocence or guilt be proven through Ancestry.com? What cases have been solved with the help of genetic genealogy? How do the police find someone from a DNA sample? Answers to these questions and many more await on Genealogy Support.
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00:00I'm CeCe Moore, genetic genealogist.
00:02I'm here to answer your questions from the internet.
00:05This is Genealogy Support.
00:13AirSignificant2006 asks, what's the most interesting discovery you've made through a DNA test?
00:18One that comes to mind is I discovered that LL Cool J's mother was adopted and she didn't
00:24know it.
00:24The DNA matches were not lining up with her parents at all.
00:27And so I was able to identify her biological parents through her DNA alone.
00:33And it was a huge discovery for them because LL Cool J had been partly raised by his maternal
00:39grandparents.
00:40So it was very significant to discover that they were not his biological grandparents at
00:46all.
00:46A Reddit user asked, how did the police actually find a person just from a DNA sample?
00:52What we are doing in investigative genetic genealogy, which is the term that refers to when we're
00:59working with law enforcement, is we are reverse engineering someone's identity from their DNA
01:04alone.
01:04And how can we do that?
01:06That is because autosomal DNA is inherited from all your ancestral lines.
01:11And so if we can identify your ancestors from who you're sharing DNA with, then we can piece
01:19your family tree back together little by little.
01:22And so even if we don't know who the DNA contributor is, we can start piecing their family tree back
01:28together based on the family trees of the people they share DNA with.
01:32So if you share DNA with four people who all descend from one set of great-great-grandparents,
01:37we know that's one piece of the criminal's family tree.
01:42And he must also be a descendant of those common ancestors.
01:46A Quirr user asks, can a person's innocence or guilt be proven through genealogy tests like
01:53Ancestry.com?
01:55Well, not directly because Ancestry.com, 23andMe, and MyHeritage, the three largest DNA databases,
02:03have barred law enforcement for using their services for criminal research.
02:09All of the genetic genealogy databases are owned by private, for-profit companies.
02:14So they get to set their own policies, procedures, and terms of service.
02:19Their reasoning is that they built those databases and those services for people to learn about
02:24their family history, not for law enforcement to find criminals.
02:28But then the smaller databases have made a different decision.
02:32Family Tree DNA, GEDmatch, and DNA Justice have specifically decided to work with law enforcement
02:38and to help us identify violent criminals, and also John and Jane Doe's.
02:43So John and Jane Doe's are people who have died without their identification, who have not
02:48been returned to their families.
02:49Their families are out there still wondering what happened to them.
02:52And we're not even allowed to use the big databases for those types of cases.
02:57Over 54 million people have taken direct consumer DNA tests, but for law enforcement cases, we
03:03are limited to about 2 million people to run these comparisons and try to identify the contributor
03:08of that DNA.
03:11ZachOutloud123 asked, what is your craziest DNA matches story?
03:14The baby switch ones are probably the craziest to me.
03:18When someone's DNA results don't match up at all with their family tree, there are only
03:23a couple of possibilities.
03:24One is they were adopted and didn't know it, but another one that we're actually finding
03:29many of is baby switches from the hospital.
03:32I've worked on dozens of those cases and I'm aware of hundreds of cases where people were
03:38switched at birth and were raised with the wrong parents and lived a life intended for
03:43someone else.
03:44It's assumed that these are accidents, but we also have some cases where the theory is that
03:51a person was purposely switching out the babies.
03:55This sometimes happened when a rich couple had a very ill baby, a sickly baby that they didn't
04:03think was going to survive, and a poor single mother, for instance, had a very healthy newborn.
04:09Sometimes they would purposely switch those out to keep the rich customers happy.
04:20Well, genetic genealogy is the combination of documentary research, or the paper trail,
04:29where you're tracing your ancestors back in time, combined with DNA.
04:34So DNA has been used for genealogical purposes for about 25 years now, and that really has
04:41helped to inform our genealogy.
04:44Everybody has brick walls, which means they can't get further back on one branch of their
04:50tree.
04:50For instance, you might not know who your great-great-grandparent is, and you're unable
04:55to find the paper trail records to identify that person.
04:59So if you turn to DNA testing, you then may be able to fill in those spots in your tree
05:05that were formerly your brick walls.
05:08Mark Cuban 42 on Reddit asks, what cases have been solved with the help of genetic genealogy?
05:14Well, over the last eight years, over 1,000 violent criminals have now been identified
05:19through genetic genealogy.
05:21I have helped law enforcement solve over 400 of those cases with just my small team.
05:27One case that comes to mind is the little girl April Tinsley.
05:31She was walking to her friend's house in Fort Wayne, Indiana, and she was kidnapped and murdered
05:38by a man named John Miller.
05:40And I helped to identify him in 2018.
05:44He was the very first person to be convicted that had been identified through genetic genealogy.
05:50In December 2018, he pled guilty to the crime and received 80 years behind bars, and he ended
05:57up dying in prison.
05:59Rondolfer asked, are Europeans really all descended from Charlemagne or anyone of that time period?
06:06The answer to that is yes.
06:08Charlemagne was the king of the Franks from 768, and he had at least 18 known children.
06:17That's not just true for Charlemagne.
06:19It's actually true for any person who lived in the ninth century in Europe who has descendants.
06:27And that is because our tree grows exponentially as you go back in time to the point where we
06:35would have more ancestors on our family tree than were alive at that point of time.
06:41A thousand years ago, we would have had over a billion ancestors, which is larger than the
06:47population at that time in history.
06:51So any person living over a thousand years ago in Europe that has descendants today is
06:57actually the ancestor of all people who have European ancestry.
07:02And that would also be true, for instance, in Asia or any part of the world, really, because
07:08our family trees grow out like this and then they start collapsing in on themselves.
07:14It's called pedigree collapse.
07:16So as your tree goes back in time, it looks more like a diamond.
07:20A user on Quora asked, what are some reasons why it's often difficult to trace your lineage
07:25or family history?
07:26Well, it really is dependent on your population group, from where your ancestors lived, because
07:33some places have much better records than others.
07:36For instance, if your ancestors are from Iceland, you might be able to trace your family tree
07:42back 30 generations.
07:44Or Switzerland has records going back over 700 years.
07:49In my own personal family tree, I've been able to trace back to the 1400s on my finish
07:55lines, and that is because they have such fantastic records.
07:58But there are many other population groups that either didn't keep records or they had them
08:04and they were destroyed.
08:05For instance, in World War I, the Irish pulped their census records due to a severe shortage
08:12of paper, meaning they destroyed those and used that raw material for other purposes.
08:18If you have Asian ancestry or Indian ancestry, there may be scrolls that trace your family
08:24tree, at least the men in your family tree, back thousands of years.
08:27But you have to be fortunate enough for those to have survived and to be able to find those.
08:32And also, if you have ancestry from the southern United States, during the Civil War, many courthouses
08:39were burned.
08:40And so you might have family records that were housed in those burnt counties, as they're
08:46called.
08:47Or if you have Ashkenazi Jewish ancestry, for instance, many of those records were destroyed
08:53during World War II.
08:54A user on Reddit asks, can someone explain the whole idea of ethnicity to me?
09:00I was taught by scientists not to use the term ethnicity in the context of DNA.
09:07Instead, we use terms like ancestral origins or biographical ancestry.
09:13And that is because ethnicity really implies more about someone's culture or traditions.
09:19Your ethnicity is really what's been passed down in your family.
09:24And so ethnicity is more of a social term.
09:29And ancestral origins or biographical ancestry is more of a scientific term.
09:36Now ethnicity is used for these tests because it's easily understood by the public.
09:41And it's good for marketing, for instance.
09:44But it's really not the most accurate term that should be used in the context of genetics.
09:52Potentialstop5998 asked, my husband and I found out that my great grandpa is his grandma's uncle,
09:57and now I'm pregnant.
09:59Should I be worried?
10:00No, you don't have to be worried about a relationship that distant.
10:04There have been many first cousin marriages throughout history, typically without issues.
10:10I believe for first cousins, there's only about a 10% likelihood that it will have a negative impact on
10:18offspring of that couple.
10:20Unfortunately, I've had to tell hundreds of people that their parents were first-degree relatives,
10:26which is parent, child, or siblings.
10:28Neural Stardust asked, how far back can we trace using DNA?
10:32For example, the family tree and the origin of life.
10:36Well, it depends which type of DNA you are utilizing.
10:40Mitochondrial DNA is passed directly from mother to child.
10:44Only women pass it on.
10:46So you received your mitochondrial DNA from your mother, who received it from her mother,
10:51who got it from her mother, and her mother, and so on, back hundreds of thousands of years.
10:55If you're using the Y chromosome that only men carry, there is a similar concept called
11:01Y-chromosomal Adam.
11:03That is the most recent man that all of men descend from, or trace back to.
11:09And he lived about 200,000 to 300,000 years ago.
11:13Now there's a big misconception that mitochondrial Eve and chromosomal Adam were a couple, and
11:19that's not true.
11:19They didn't know each other, although they both did come from Africa around the same time period.
11:25A Quora user asked, how long does it commonly take to solve a case using high-tech sleuthing
11:32like genealogy websites?
11:34The most quickly I've been able to help law enforcement solve a case is in 30 minutes.
11:40And the longest it has taken is eight years and counting.
11:44I've been trying to identify a little girl known as St. Louis Jane Doe for almost eight
11:51years now.
11:52And that is because she comes from the African-American population group, of which we have less representation.
11:59And also we run into that genealogical brick wall at the 1870 census, where formerly enslaved
12:07individuals were not enumerated by name prior to that.
12:11This one is from Royal Perp.
12:14I'd bite the bullet and take a DNA test.
12:16I want to see how far back they can trace my ancestry.
12:20Now we're just talking about your own DNA, not fossil DNA.
12:24It is the same as far as your Y-DNA can be traced back hundreds of thousands of years.
12:29Your mitochondrial DNA, at least 150,000 years.
12:33But your autosomal DNA is really inherited primarily from your closer ancestors.
12:40We have genealogical family trees and genetic family trees.
12:44Genealogical family trees are all your ancestors as far back as you can go.
12:49Genetic family tree is just the people who have contributed to your genome.
12:54So we receive DNA from all of our third-grade grandparents and almost certainly all of our
12:59fourth-grade grandparents.
13:00But when you get further back in the tree, some of those ancestors start falling off your
13:05genetic family tree.
13:06And so now you're only inheriting DNA from a subset of your ancestors.
13:12Engineering Lumpy asks, why do siblings get different DNA percentages?
13:16So he's referring to the ethnicity portion of the DNA results.
13:22And the reason that siblings don't get the exact same results is because they inherit
13:28different DNA from their parents.
13:30We overlap with our siblings on about 50% of the DNA.
13:33So there's some portions where we inherit the exact same DNA from both parents.
13:37There's some portions of our DNA where we inherit the same DNA from one parent but not
13:41the other.
13:42And then there are some parts of our DNA where we don't inherit the same DNA from either parent.
13:48User mando-monroe00 asks, I think I want to take the ancestry DNA test, but how accurate
13:55is it?
13:56It's important to understand that there are two different parts of the results you receive
14:00when you take a DNA test.
14:02One of those is to find relatives.
14:05And those are highly accurate.
14:07If they tell you that someone is your relative, they are.
14:10I see a lot of people who think it's a mistake when they get a match on Ancestry, for instance,
14:17that says it is half-sibling.
14:19And people need to understand that can never happen by mistake.
14:24If you share about 25% of your DNA with someone, that is a very close relative to you.
14:29But the other part of the test that gets a lot more attention is the ethnicity estimate.
14:35That is less reliable in that it is a developing science.
14:40They are very good at telling you what parts of the world you come from on a continental
14:45level.
14:46Meaning the Americas versus Africa versus Europe versus Asia.
14:50That is relatively easy to do.
14:52But when they are giving you these very specific labels, very granular results, that's much
14:58more difficult to do.
14:59And that's because there's been so much migration throughout history.
15:03PsychoBenus asked, do you realize how much DNA you share with your cousin versus your third
15:09cousin?
15:09So with your first cousins, you'll share on average 12.5% of your DNA.
15:14And your third cousins, you'll share on average less than 1% of your DNA.
15:18And you might not share any DNA at all with your third cousin.
15:22Well that's all the questions we can cover today.
15:24I hope you learned something.
15:26Until next time.
15:27Until next time.
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