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Friends are as genetically similar as fourth cousins

pnas.org

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Re: Friends are as genetically similar as fourth cousins

#31

Post by bobwaycott »

mod wrote: post #27
Throwaway23412 wrote: post #25

Earlier quoted context omitted.

Edit: Nvm. I am more confused than I thought.

I've always wondered about this one: My father's first-cousin-once-removed is what to me?

Your second cousin if you share the same great-grandparents.

Edit: Ugh, this gets confusing. I was mistaken. I'd originally included the once-removed, but that appears to be incorrect. Or I'm still mistaken. :)

A first cousin once-removed signifies one person's grandparent is the other's great-grandparent.

Perhaps this cousin chart would help: https://en.m.wikipedia.org/wiki/Cousin#Relationship_charts

Just plot yourself and the cousin-in-question by where your shared nth-grandparent lies.

Re: Friends are as genetically similar as fourth cousins

#32

Post by jacobolus »

runholm wrote: post #16
mnbcvx wrote: post #13

Earlier quoted context omitted.

> second cousins Didn't stop my great grandparents :) My mom's side is Mennonite, which is also a very tight knit community. When my grandma sends random pictures from in and around Goshen, Indiana, my wife has commented multiple times "whoa that guy in the background really looks like you!"

Really not an issue with second cousins. Second cousins are genetically different enough that issues with the children are just barely more common in non-related couples.

From a genetic perspective, even occasional first-cousin marriage is not really a problem. The problems start when you have several generations of cousin and sibling marriages, allowing homozygous recessive alleles to concentrate.

Re: Friends are as genetically similar as fourth cousins

#34

Post by alexwagg »

mod wrote: post #27
Throwaway23412 wrote: post #25

Earlier quoted context omitted.

Edit: Nvm. I am more confused than I thought.

I've always wondered about this one: My father's first-cousin-once-removed is what to me?

I think, if your father's cousin-once-removed is a generation below him, then he/she is your first-cousin. While a generate above you father would signal first-cousin-twice-removed...

Thoughts?

Re: Friends are as genetically similar as fourth cousins

#35

Post by qq66 »

astazangasta wrote: post #8

This is a dataset designed to study genetics in a cohort of mostly white people from Framingham, MA. How can anyone claim to be able to draw conclusions about the genetics of friendship from this cohort? This is such a biased dataset I can't believe this got published. For the record, I am Indian, my best friend growing up was Italian, my current best friends are a Russian Jew, a Scotch Irish mix from Woburn, and a C…

The genes that you get from your ethnicity are a small fraction of your overall genome. There are tons of other genes that affect things like your height, your interest in music, etc, that could strongly affect your friend selection.

Re: Friends are as genetically similar as fourth cousins

#36

Post by astazangasta »

Manishearth wrote: post #28
astazangasta wrote: post #8

This is a dataset designed to study genetics in a cohort of mostly white people from Framingham, MA. How can anyone claim to be able to draw conclusions about the genetics of friendship from this cohort? This is such a biased dataset I can't believe this got published. For the record, I am Indian, my best friend growing up was Italian, my current best friends are a Russian Jew, a Scotch Irish mix from Woburn, and a C…

They explicitly call this out and apply population stratification later in the paper.

Yeah, which means the extensibility of these claims is exactly as good as those corrections, which can't possibly hope to model the missing information (the actual genetic distribution of friends).

Re: Friends are as genetically similar as fourth cousins

#37

Post by astazangasta »

qq66 wrote: post #35
astazangasta wrote: post #8

This is a dataset designed to study genetics in a cohort of mostly white people from Framingham, MA. How can anyone claim to be able to draw conclusions about the genetics of friendship from this cohort? This is such a biased dataset I can't believe this got published. For the record, I am Indian, my best friend growing up was Italian, my current best friends are a Russian Jew, a Scotch Irish mix from Woburn, and a C…

The genes that you get from your ethnicity are a small fraction of your overall genome. There are tons of other genes that affect things like your height, your interest in music, etc, that could strongly affect your friend selection.

And I got those in some other way than my ancestry...?

Re: Friends are as genetically similar as fourth cousins

#38

Post by popmystack »

qq66 wrote: post #35
astazangasta wrote: post #8

This is a dataset designed to study genetics in a cohort of mostly white people from Framingham, MA. How can anyone claim to be able to draw conclusions about the genetics of friendship from this cohort? This is such a biased dataset I can't believe this got published. For the record, I am Indian, my best friend growing up was Italian, my current best friends are a Russian Jew, a Scotch Irish mix from Woburn, and a C…

The genes that you get from your ethnicity are a small fraction of your overall genome. There are tons of other genes that affect things like your height, your interest in music, etc, that could strongly affect your friend selection.

I'm not sure you understand the whole genetics thing.

Re: Friends are as genetically similar as fourth cousins

#39

Post by civilian »

milesskorpen wrote: post #26
skylan_q wrote: post #9

Earlier quoted context omitted.

Where our family is from the priests wouldn't allow marriage between 6th cousins. My grandfather was 6th cousins three times removed from my grandmother. (so she was 9 generations away from common ancestors with him) They had to get written permission from the bishop to get married.

Sounds like they basically penalized record keeping ...

Ah, it was probably the Church who was keeping the records in the first place.
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