23&me not using Y chromosome for DNA relatives feature

[Touijer]

Many people wrongly think that Y DNA has no value; however, it is important because you have about 2% of your DNA in common with others who belong to the same group. 23&Me identifies DNA relatives by using autosomal chromosomes and the X chromosome, but they do not use Y chromosome analysis in their method.

This phenomenon I discovered today is interesting. Why would they test X and autosomal but not Y for dna relatives? The most probable answer is everyone would get millions of matches but they made people who don’t read their blogs successful in denying Y chromosome and only looking at autosomal matches


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Article link (https://customercare.23andme.com/hc/en-us/articles/212170958-DNA-Relatives-Detecting-Relatives-and-Predicting-Relationships)

As you can see they wrote it in very small letters, suspicious. People should stop blindly believing everything a commercial company says. Why include the X and not Y? At least mention it in big letters so people know what they see instead of needing to go into one of their articles and see it in small letters.

[Boudin]

Why would they test X and autosomal but not Y for dna relatives?

Maybe because only 5% of the Y-chromosome undergoes crossover with the X-chromosome (https://www.thetech.org/ask-a-geneticist/articles/2009/ask295/), so it changes too slowly to be useful for finding close relatives. Finding distant relatives based on paternal haplogroups is a niche that companies like FamilyTreeDNA fill, though.

[gixajo]

...it is important because you have about 2% of your DNA in common with others who link[/URL]

s.

Nope, you don´t have a 2% of your DNA in common with another one with whom you share Ydna, unless you share a exact whole Y chromosome with that person and this only happenswhen that person is your monozygotic twin.

Another Z280 and me share some dozens of SNPs, and someone with my BY27340 few SNPs more. I think you misunderstood that of "2%".

[kingmob]

Many people wrongly think that Y DNA has no value; however, it is important because you have about 2% of your DNA in common with others who belong to the same group. 23&Me identifies DNA relatives by using autosomal chromosomes and the X chromosome, but they do not use Y chromosome analysis in their method.

This phenomenon I discovered today is interesting. Why would they test X and autosomal but not Y for dna relatives? The most probable answer is everyone would get millions of matches but they made people who don’t read their blogs successful in denying Y chromosome and only looking at autosomal matches


125103

125104

Article link (https://customercare.23andme.com/hc/en-us/articles/212170958-DNA-Relatives-Detecting-Relatives-and-Predicting-Relationships)

As you can see they wrote it in very small letters, suspicious. People should stop blindly believing everything a commercial company says. Why include the X and not Y? At least mention it in big letters so people know what they see instead of needing to go into one of their articles and see it in small letters.


Y-chr. is a league of its own.

In all seriousness, that's why in these tests, if you are a man, your ancestry is represented as 51.5%ish maternal and 48.5%ish paternal, you have 23 X chrs from your mother and 22 X chrs from your father. It's the same with all autosomal tests from all companies.

TLDR: If you are a man, your maternal side will have a larger % in your autosomal representation.

[Touijer]

Nope, you don´t have a 2% of your DNA in common with another one with whom you share Ydna, unless you share a exact whole Y chromosome with that person and this only happenswhen that person is your monozygotic twin.

Another Z280 and me share some dozens of SNPs, and someone with my BY27340 few SNPs more. I think you misunderstood that of "2%".

You don’t share 2% but around 1.9%, still it’s a lot.

[Touijer]

Maybe because only 5% of the Y-chromosome undergoes crossover with the X-chromosome (https://www.thetech.org/ask-a-geneticist/articles/2009/ask295/), so it changes too slowly to be useful for finding close relatives. Finding distant relatives based on paternal haplogroups is a niche that companies like FamilyTreeDNA fill, though.

I think it’s because many people will get millions of relatives so the whole point would be boring, or they want to include women too, so they’re not left out hence why they use X chromosome that every gender has but not Y that only one has.

[kingmob]

Ιt's because they don't test STRs and SNPs for y-chr, the price would skyrocket otherwise.

You need to cough up the dough for that.

[Touijer]

Ιt's because they don't test STRs and SNPs for y-chr, the price would skyrocket otherwise.

You need to cough up the dough for that.

They do test some SNP’s just to give their customers a basic haplogroup but effectively they would need to make a test similar to FTDNA’s Big Y for it to be accurate.

They’re just a commercial company so it would just be a bad decision for them, better give the population what they want which is fancy numbers

[gixajo]

You don’t share 2% but around 1.9%, still it’s a lot.

No, you are wrong. Did you read what I´ve posted?

Around 2% is the total of whole Y (and is also simplist and wrong because Y is shorter and contains less information than most of any other previous 44 chromosomes, and not sure if X is also longer than Y) and just some parts of the Y has SNPs (or STRs , that are just chunks of repetitions of some SNPs(actually chains of nucleotides but not "single") in the same order) are used to determine Ydna haplogroups.

Check your BIG Y if you have it and you can see what I am telling you.

[Kess]

Nope, you don´t have a 2% of your DNA in common with another one with whom you share Ydna, unless you share a exact whole Y chromosome with that person and this only happenswhen that person is your monozygotic twin.

Another Z280 and me share some dozens of SNPs, and someone with my BY27340 few SNPs more. I think you misunderstood that of "2%".

Dude, you are talking to a flat earther just ignore him in serious matters.

[Touijer]

No, you are wrong. Did you read what I´ve posted?

Around 2% is the total of whole Y (and is also simplist and wrong because Y is shorter and contains less information than most of any other previous 44 chromosomes, and not sure if X is also longer than Y) and just some parts of the Y has SNPs (or STRs , that are just chunks of repetitions of some SNPs(actually chains of nucleotides but not "single") in the same order) are used to determine Ydna haplogroups.

Check your BIG Y if you have it and you can see what I am telling you.

It’s not only me that says it, ChatGPT says it too. I think you’re mixing up things.

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Every male regardless of haplogroup shares around 0,5% of the Y chromosome which is basic genetic material. You share 100% of that Y dna with your father, the same mutations and genetic markers. Depending on the haplogroup and subclade that figure can be 90% with other members of your subclade because of shared mutations and genetic markers. Every haplogroup has genetic markers unique to them, it’s simple really.

[Boudin]

I think it’s because many people will get millions of relatives so the whole point would be boring, or they want to include women too, so they’re not left out hence why they use X chromosome that every gender has but not Y that only one has.

It's because the X chromosome undergoes normal crossover in females, so it's rate of change and thus utility for determining ancestry and relatives is comparable to that of the other chromosomes.

[Boudin]

23andMe has actually published an article discussing the challenges of using the X-chromosome in ancestry estimation, Challenges of accurately estimating sex-biased admixture from Xchromosomal and autosomal ancestry proportions (https://www.cell.com/ajhg/pdfExtended/S0002-9297(22)00546-8#articleInformation).