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Everyone on Earth is your cousin (2015)

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Re: Everyone on Earth is your cousin (2015)

#61

Post by tzs »

fastball wrote: post #28
tzs wrote: post #7

There are a few particularly interesting points when you go back up your ancestor tree. First, there is a point where some ancestor of yours is an ancestor of everyone else currently living (and so will also be an ancestor of everyone else to come). This is the "most recent common ancestor" point. Go farther back and you reach the "identical ancestors point" (also known as the "all common ancestors point" or the "gen…

Maybe I'm stupid but I'm not sure I understand the difference between most recent common ancestor and the identical ancestors point. Can someone explain differently?

Another way to think of it is at any given time in the past, you can put any given person into one of three classes:

1. Nobody alive today is descended from them,

2. Some people alive today are descended from them, and some people alive today are not descended from them,

3. Everybody alive today is descended from them.

Go back a short time, and everybody is in groups #1 or #2.

Go back farther and you reach a time where there is someone in group #3.

Keep going back and you reach a point where nobody is left in group #2.

The most recent common ancestor point is when group #3 going back gets its first member.

The identical ancestor point is when group #2 going back loses its last member.

Re: Everyone on Earth is your cousin (2015)

#62

Post by unbanned »

ngngngng wrote: post #32

Pro tip, get the old folks talking, and take out your phone to record. Whatever they're talking about, even if they're talking about nothing at all. They'll all be gone soon, and having video of your boring everyday interactions with them is better than having only your memories of them.

Why? You'll be forgotten about too in about 40 years

Re: Everyone on Earth is your cousin (2015)

#63

Post by cambaceres »

unbanned wrote: post #62
ngngngng wrote: post #32

Pro tip, get the old folks talking, and take out your phone to record. Whatever they're talking about, even if they're talking about nothing at all. They'll all be gone soon, and having video of your boring everyday interactions with them is better than having only your memories of them.

Why? You'll be forgotten about too in about 40 years

You are right, so why don't we all just kill ourselves? Nothing lasts anyways, so what's the point of all this really. Except of course, if you learn to appreciate what you have right now...

Re: Everyone on Earth is your cousin (2015)

#64

Post by Merrill »

First cousins share 1/8 of their DNA, which is sort of meaningful. Second cousins share 1/32 of their DNA or about 3%, which is really marginal in terms of their being any resemblance or affinity due to DNA. By the time you get to third cousins the shared DNA is down to 1/128 or less than 1%.

So I've lost interest in tracking down any relatives beyond second cousins.

Re: Everyone on Earth is your cousin (2015)

#65

Post by scandox »

Merrill wrote: post #64

First cousins share 1/8 of their DNA, which is sort of meaningful. Second cousins share 1/32 of their DNA or about 3%, which is really marginal in terms of their being any resemblance or affinity due to DNA. By the time you get to third cousins the shared DNA is down to 1/128 or less than 1%. So I've lost interest in tracking down any relatives beyond second cousins.

I'm very ignorant about these matters but I thought we all shared the vast majority of our DNA? I mean as humans are we not all 99.9% the same ... DNA wise?

What does the 1/8 mean in this context?

Re: Everyone on Earth is your cousin (2015)

#66

Post by frereubu »

"our own personal history — which we really should know quite well..."

I have to admit I don't really get this. I know this is a common sentiment, but I'm just not really interested. Every now and then my mother will drop a tidbit like "when I was horse riding around the pyramids..." and it'll be interesting. But in practical terms there's an infinite amount of things she could tell me and I'm not going to hear it all before she dies. I know there are others who are fascinated by these kinds of things, and I have nothing against that, but it mostly leaves me cold.

It's an interesting juxtaposition to my interest in history - some of her stories about being sent to live with relatives in Ireland during WWII tie in nicely to my interest in that period - but I don't find it particularly enlightening on a personal level. I suppose it was best expressed during a series of programmes on Scotland by Jonathan Meades, where he's talking about the ancestry industry that's so strong there - "why should I be interested if my great, great, great grandparent with rickets hobbled alongside this river with their sheep?"

Re: Everyone on Earth is your cousin (2015)

#67

Post by zzzzzzzza »

scandox wrote: post #65
Merrill wrote: post #64

First cousins share 1/8 of their DNA, which is sort of meaningful. Second cousins share 1/32 of their DNA or about 3%, which is really marginal in terms of their being any resemblance or affinity due to DNA. By the time you get to third cousins the shared DNA is down to 1/128 or less than 1%. So I've lost interest in tracking down any relatives beyond second cousins.

I'm very ignorant about these matters but I thought we all shared the vast majority of our DNA? I mean as humans are we not all 99.9% the same ... DNA wise? What does the 1/8 mean in this context?

he's probably talking about snps, single nucleotide polymorphisms, which are pretty much the places where human dna is different from one another.

Re: Everyone on Earth is your cousin (2015)

#68

Post by Tenoke »

tzs wrote: post #7

There are a few particularly interesting points when you go back up your ancestor tree. First, there is a point where some ancestor of yours is an ancestor of everyone else currently living (and so will also be an ancestor of everyone else to come). This is the "most recent common ancestor" point. Go farther back and you reach the "identical ancestors point" (also known as the "all common ancestors point" or the "gen…

>Note that this is after the Neanderthals went extinct. It follows that since there are people alive today with Neanderthal ancestry, there must have been people alive at the identical ancestor point who had Neanderthal ancestry and who have descendants alive today, and so by the definition of the identical ancestor point everyone alive today is a descendent of all such people.

Not by definition. Adam is older than Eve which suggests we are descendant from multiple mate's of Eve. Some might have had neanderthal ancenstry, some might have not.

Re: Everyone on Earth is your cousin (2015)

#69

Post by [deleted] »

irrational wrote: post #25
mettamage wrote: post #13

Earlier quoted context omitted.

Another thing I find interesting is that your family right now are the most closest humans related to you. When you go back in time or forward in time, the relatedness dilutes.

Even then, you and your sibling could, statistically, share zero genes (you each get 50% from each parent and it is possible you each got a different 50%). Your own parents and children are the closest relatives you have since you are guaranteed to have 50% of your parent’s genes and same with your children.

[deleted]

Re: Everyone on Earth is your cousin (2015)

#70

Post by wara23arish »

sammalloy wrote: post #4

This article made me wonder about an idea I’ve been thinking about for years. There are people who have prosopagnosia, also known as face blindness, the inability to recognize familiar faces. I’m not exactly a super recogniser, but I have an unusual ability to remember a face. Beyond these two extremes, would it be possible to recognize a face you’ve never seen before as a possible relative, and has such a thing ever…

Im not sure if I understand you correctly. But that’s not uncommon where Im from. People will sometimes stop to ask you if you’re related to X sincerely you look familiar. The person doesn’t have to be a relative.

Example: I’ve had a 4th grade teacher recognize my uncle in a setting totally unrelated to school. He happened to meet my uncle and noticed a resemblance.

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