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23andMe’s Historical Matches
#16
(03-22-2024, 10:24 PM)brunolord15 Wrote:
(03-22-2024, 10:10 PM)Tolan Wrote:
(03-22-2024, 06:34 PM)brunolord15 Wrote:
(03-22-2024, 06:30 PM)leonardo Wrote:
(03-22-2024, 06:01 PM)brunolord15 Wrote: one question , how is possible match with something so old? for example a match with ancient sample , what probability to be true?

Through y-DNA or mtDNA you can go back about as far as possible, especially y-DNA. Autosomal DNA might go back 7 generations, at most. That's why asked if they were doing any autosomal matches, altghough I wouldn't call that "ancient."
but how works this matches for example with viking samples that 23andme have? matchs is only with Y and mtdna?

Only autosomal:
https://blog.23andme.com/articles/23andm...lBw38DvBfk
Quote:While previous ancestry features allowed customers to find out if they were genetically connected via their maternal or paternal lines, this new feature searches across the whole genome to connect members to historical individuals who lived hundreds or sometimes thousands of years ago by finding identical segments of DNA in their genomes.

Like 23andMe’s DNA Relatives feature, Historical Matches searches for shared segments of DNA between 23andMe+ Premium members and historical individuals. The feature identifies matches by finding segments and looking at the length of DNA that subscribers share with these historical individuals. Creating quality thresholds for how long a shared segment must be for a match makes it unlikely that there would be “false positive” matches.

It is entirely possible, and even probable, that small segments of 5 centimorgan or less are preserved for centuries.
On the other hand, phasing with a parent is necessary for the segment to be valid. It is not with their threshold criterion that will make them credible in my opinion.
what companies offers this feature?

DNA genics offer this feature. Shared Roots: Ancient Oceania and Africa, for the moment.

[Image: dna-genics.png] [Image: dna-genics-matching.png]

Compared to 23andme, not sure about the accuracy or relevance. Though they explain a bit how they do it.
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#17
(03-22-2024, 10:10 PM)Tolan Wrote:
(03-22-2024, 06:34 PM)brunolord15 Wrote:
(03-22-2024, 06:30 PM)leonardo Wrote:
(03-22-2024, 06:01 PM)brunolord15 Wrote:
(03-22-2024, 03:37 PM)JMcB Wrote: Thanks, now I got it! I have 8 historical matches.

one question , how is possible match with something so old? for example a match with ancient sample , what probability to be true?

Through y-DNA or mtDNA you can go back about as far as possible, especially y-DNA. Autosomal DNA might go back 7 generations, at most. That's why asked if they were doing any autosomal matches, altghough I wouldn't call that "ancient."
but how works this matches for example with viking samples that 23andme have? matchs is only with Y and mtdna?

Only autosomal:
https://blog.23andme.com/articles/23andm...lBw38DvBfk
Quote:While previous ancestry features allowed customers to find out if they were genetically connected via their maternal or paternal lines, this new feature searches across the whole genome to connect members to historical individuals who lived hundreds or sometimes thousands of years ago by finding identical segments of DNA in their genomes.

Like 23andMe’s DNA Relatives feature, Historical Matches searches for shared segments of DNA between 23andMe+ Premium members and historical individuals. The feature identifies matches by finding segments and looking at the length of DNA that subscribers share with these historical individuals. Creating quality thresholds for how long a shared segment must be for a match makes it unlikely that there would be “false positive” matches.

It is entirely possible, and even probable, that small segments of 5 centimorgan or less are preserved for centuries.
On the other hand, phasing with a parent is necessary for the segment to be valid. It is not with their threshold criterion that will make them credible in my opinion.

I would go much further, with 5 cM being possibly more than thousand years old. I have segments larger than 25 cM which are for certain 300 years old and 10-12 cM which must be at least 500 years old, presumably a couple of centuries older, but that's less certain than the 500 years threshold.

The segment threshold is critical, as when I use MyTrueAncestry, which is likely to be less reliable, most matches disappear when I use 300 SNP as the limit and there is little confirmation with my parents still - so likely false or unreliable.  

Europeans can't get that feature at 23andMe by the way.
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#18
I had signed up to 23andMe+ a while ago for the extra health reports and relative matches. The new historical matches feature is a fun addition, but I think anyone upgrading for that alone would be underwhelmed. 

There are still relatively few ancient samples in their database. These are all of the categories listed on the site.
   

Of my 14 matches, most are to Viking Era North European samples. I also have a few matches to ancient Indo-Europeans found in modern Kazakhstan, which to me was the neatest thing. 
   
   
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#19
(03-23-2024, 03:51 PM)DeParis Wrote: I had signed up to 23andMe+ a while ago for the extra health reports and relative matches. The new historical matches feature is a fun addition, but I think anyone upgrading for that alone would be underwhelmed. 

There are still relatively few ancient samples in their database. These are all of the categories listed on the site.


Of my 14 matches, most are to Viking Era North European samples. I also have a few matches to ancient Indo-Europeans found in modern Kazakhstan, which to me was the neatest thing. 

I believe the Beethoven sample isn't actually his.
https://www.whodoyouthinkyouaremagazine....thoven-dna
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#20
(03-23-2024, 03:51 PM)DeParis Wrote: I had signed up to 23andMe+ a while ago for the extra health reports and relative matches. The new historical matches feature is a fun addition, but I think anyone upgrading for that alone would be underwhelmed. 

There are still relatively few ancient samples in their database. These are all of the categories listed on the site.


Of my 14 matches, most are to Viking Era North European samples. I also have a few matches to ancient Indo-Europeans found in modern Kazakhstan, which to me was the neatest thing. 

I may have missed it but I didn't see autosomal DNA specifically stated in the 23andme announcement.
Here in UK, the family member tested with the V5 chip now has 10 Historical Matches - all from the Viking Age. In each case it reports that there is a single shared segment, ranging in size from 10cM for the closest to 4.02cM for the furthest. I find it hard to think of a 10cM segment surviving so long unless it is Y-DNA or mtDNA (unless it conferred some great advantage or is in part of the autosomal DNA that is usually ignored because it doesn't change much). Also, I know our Y-DNA matches Vikings (Big-Y result). Nine of the ten 23andme Historical Matches are men. However, there is one woman (and there is zero chance that that is a match to the mtDNA unless that Viking in Greenland had East Asian mtDNA). So I suppose they are at least partly using autosomal DNA in some form for this test.
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#21
As already noted in this thread, these matches are only autosomal.

I would not be surprised to have a segment of 10 cM with historical people because I have matches with 10 cM (are more - real by phasing with my father or mother) with foreigners from my country and for whom we cannot have common ancestors less than one millenium. Maybe several millennia..

And with a cousin, it’s double the generation gap than with a historical ancestor!

The big problem is that I don't have confidence because the only method that seems valid to me is real phasing with at least one of the parents.
On another site, I calculated that more than 85% of the matches announced were not true segments, but a mixture of alleles from my father and my mother.
If the segment is not phased, an heterozygous allele matches with everyone. It is only through homozygotes that it is possible to differentiate the segments.
I am amazed of the incompetence of the DNA companies!
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#22
(03-22-2024, 10:24 PM)brunolord15 Wrote:
(03-22-2024, 10:10 PM)Tolan Wrote:
(03-22-2024, 06:34 PM)brunolord15 Wrote: but how works this matches for example with viking samples that 23andme have? matchs is only with Y and mtdna?

Only autosomal:
https://blog.23andme.com/articles/23andm...lBw38DvBfk
Quote:While previous ancestry features allowed customers to find out if they were genetically connected via their maternal or paternal lines, this new feature searches across the whole genome to connect members to historical individuals who lived hundreds or sometimes thousands of years ago by finding identical segments of DNA in their genomes.

Like 23andMe’s DNA Relatives feature, Historical Matches searches for shared segments of DNA between 23andMe+ Premium members and historical individuals. The feature identifies matches by finding segments and looking at the length of DNA that subscribers share with these historical individuals. Creating quality thresholds for how long a shared segment must be for a match makes it unlikely that there would be “false positive” matches.

It is entirely possible, and even probable, that small segments of 5 centimorgan or less are preserved for centuries.
On the other hand, phasing with a parent is necessary for the segment to be valid. It is not with their threshold criterion that will make them credible in my opinion.
what companies offers this feature?

(03-29-2024, 04:13 PM)Tolan Wrote: As already noted in this thread, these matches are only autosomal.

I would not be surprised to have a segment of 10 cM with historical people because I have matches with 10 cM (are more - real by phasing with my father or mother) with foreigners from my country and for whom we cannot have common ancestors less than one millenium. Maybe several millennia..

And with a cousin, it’s double the generation gap than with a historical ancestor!

The big problem is that I don't have confidence because the only method that seems valid to me is real phasing with at least one of the parents.
On another site, I calculated that more than 85% of the matches announced were not true segments, but a mixture of alleles from my father and my mother.
If the segment is not phased, an heterozygous allele matches with everyone. It is only through homozygotes that it is possible to differentiate the segments.
I am amazed of the incompetence of the DNA companies!

What you found is worrisome. I do not have your skills. But just by observation, compared to 23andme and Ftdna, myheritage especially gives me hundreds of matches of about 10 cm that none of my parents have. Though when it happens those match fit the respective area of origins of my parents: north west europe and the balkan.

Lastly, also a "myheritage thing" , my parents and I have dozens of questionnable Finnish match in the range of 6 cm to 10 cm.
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