Why You DON’T Descend From All Your Ancestors…

Why You DON’T Descend From All Your Ancestors…

Chapters:
0:00 Intro
0:46 Your DNA and How You Inherit It
2:25 Y-DNA, Mitochondrial DNA & Autosomal DNA
3:37 Why You DON’T Descend From All Your Ancestors
4:31 Recent Generations Not So Simple
5:51 Exponential Genealogical Ancestors
7:20 How Many Generations Back Do You Inherit DNA From?
8:25 Are You Related to the King of the Franks? Charlemagne
8:43 The Most Recent Common Ancestor of All Living Humans
9:26 Siblings
10:25 Key Takeaways & Your Future DNA

Do you descend from all of your ancestors? Well yes and no at the same time. Let me explain. Now let’s first quickly look at your DNA and how your parents pass on genetic information. Well DNA obviously exists in every cell in your body and holds your genetic code, making up your body’s instruction manual. DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix. Each strand has a backbone made of alternating sugar and phosphate groups.

Sources:

Testing Family Members with AncestryDNA®

Humans Are All More Closely Related Than We Commonly Think | Scientific American

How much of your genome do you inherit from a particular ancestor? | gcbias

Where did your genetic ancestors come from? | gcbias

How many chromosomes do people have?: MedlinePlus Genetics

Humans Are All More Closely Related Than We Commonly Think | Scientific American

Are you related to a King? Why you might carry royal DNA - BBC Future

So you’re related to Charlemagne? You and every other living European… | Adam Rutherford | The Guardian

Creative Commons Imagery:

#ancestry #dna #family

[celtichistorydecoded]

Thanks for watching! Please let me know your thoughts below and if you have traced your ancestry and what you found out...

[peterdixon]

I traced my lineage back as far as my parents, who were livid. Otherwise, I could watch these videos all day. Excellent work yet again, sir.

[Rainbowdust]

In building my family tree, I discovered that the mother of my paternal grandfather was the product of a marriage between two first cousins. That information continues to blow my mind a little.

[SkBettty]

I am my own 8th cousin, according to genealogy records. Massachusetts Colony had some wild times! 😂

[ESCAGEDOWOODWORKING]

You're always balanced according to the data, and present it well.

[Alan-lvrw]

My family traced back to England in 1730. 100% English. But my Ancestry DNA was 100% Irish. You never know what to expect from those tests.

[BobbieElmihi]

In my family we have 7 siblings total and 6 came out with ice blonde hair and then there was little old me, the only redhead. Then I had 4 children and only one is a redhead.

My sister and I did the ancestry test, not knowing the other did, and she came back with higher Swedish dna and I had more Scottish/irish.


I had no idea that this happens but it did explain a whole lot. We also have big gaps in height too. I am 5’10, my other sister is 6’ and 2 brothers are around 6’3 10:13 the rest are considerable shorter.
We are all blue eyed like our dad tho..and blue eyes seem dominant in my family because it’s around 90% between the children and grandchildren as well.

I had always thought this was due to our parents (dad was 6’4 and mom barely 5’) but then my children’s dad is 6’ and I’m (again) 5’10 and our kids are shorter than both of us. The 2 girls are a little over 5’.

It makes more sense now but how crazy is all of this?!?!

[andrewnorrie]

Further to my DNA testing I am a direct descendent of Birger Jarl of Sweden who lived from 1210 until 1266 making him my 32nd great grandfather . I am I1M253a2b and we all have a common ancestor who lived about 5000 years ago in Southern Sweden, though some researchers give the lower River Elbe basin as its origin .Time to the most recent common ancestor is about 2600 years .

[annecarter]

Really great explanation of a complex subject! Many thanks!!!!

[wolverineeagle]

My great-grandfather was born in 1875 in Italy. That’s three generations away from me.

7 generations would go back into the early 18th century.

[connoroleary]

In the UK we are fortunate in having surname, some of which go back over a thousand years.

Most people in the British Isles have King Edward III as a common ancestor.

[TheEggmaniac]

Good explanation of what can be complicated and confusing subject.

[eyetrollin]

My sister got cancer last year so she went for genetic testing boy the doctor was shocked when he came out and looked at my fair-skinned blonde haired blue-eyed sister he actually asked her do you know your ancestry, she's oblivious to these things so I think she told him know but I know our family's history back as far as 2000 years on one side and even further on another.

But what the genetic doctor told my sister was interesting to even me not only are there large amounts of denisovan and Neanderthal but we have all three ghost lineages. I had to explain to my sister what a ghost lineage is and where they came from in our family tree.

I do not have the skull shape of a modern human, I am far stronger than I should be I've never broken a bone and I have lived a very intense life.

Oh and according to the genetic testing my sister shouldn't have cancer I knew this ahead of time because no one else in our family extended family anywhere has ever had cancer, , , she got this fast acting cancer within two years of the shot, , the same shot that killed my fiance 4 days after he took it

[TyrSkyFatherOfTheGods]

I studied my ancestry, and was surprised to find out how sedentary both my maternal and paternal ancestors were: from the same general regions of Aberdeenshire and Staffordshire - for centuries.

[godsavethequeen]

Here’s what I’m curious about. If you probably don’t have your great great great grandparents or uncles DNA, how were they able to confirm Richard the III’s body with the DNA of his great great whatever nephew in 2012?

[connielocke]

1 brother and I took Ancestry dna test. Have same parents but he looks like Dad and I look like Mom. Ancestry thrulines show some same connections and a few that only match either him or me, not both. Weird but interesting.

[Josephmalenab]

Thanks for the video it explains things More the knowledge more the wisdom cheers

[garyedwardgray]

I’m still wondering what the answer is. I mean, I’m a scientist myself. I get the math. 7 generations is where you hit over 100 ancestors, so the amount inherited is less that 1%. BUT we also have more than 100 genes. That’s why the ancestry testing sites can break it down to tenths, albeit with low accuracy. And that accuracy will likely improve over time with further research. So, the REAL question is NOT: “At what point does your ancestor count exceed 100?” (7 generations). The REAL question is, at what point does your ancestor count exceed the unique gene count (excluding genes that all humans have that are the same)? THAT is the point at which genetic DNA inheritance will hit the 50-50 shot, NOT at 7 generations. True, the amount of genetics inherited from any one individual at that point may be minuscule and, indeed, there is an increasing chance, with every generation, that it’s zero. But that point is NOT 7 generations. That’s using the arbitrary 1% threshold. The threshold we need to use is 1% of the genes that vary across humans. One generation beyond that and THEN it’s less than a 50/50 shot that you’ve inherited any genetic material from those ancestors. That’ll be back more than seven generations. But how much more? One more generation? Two more? Three more? Five more? Ten more?

I’d honestly like to know the answer, as I have some fascinating genealogical history. Am I actually blood related to these folks or not. At what point does that disappear (or become less than a 50/50 chance). Seven generations is incorrect. That’s 1%. But if we have 200 unique genes then 0.5% would be statistically significant, so eight generations would work. And what if it’s 400 genes? Or 800? Or 1600? Or 3200?

I think I read somewhere that it’s about 3000. But I’m absolutely unsure of that. ***IF*** that’s the case, you can go back 12 generations (not seven) and have better than a 50/50 shot of inheriting DNA from them.

We need to do the math correctly. 1% isn’t the proper threshold. Seven generations is incorrect. It needs to be based on the number of unique genes that are available to be inherited. If that’s 100 (and I don’t think it is), then seven generations remains correct. But I’m almost certain it’s NOT 100. So…….. what’s the answer?

I hope you understand the point I’m raising. The oft-used seven generation explanation is mathematically flawed. So much so that we can even say it’s irrelevant. 1% is just a random number if 1% of the unique genes you inherit is 10 or 20 or 100. 1% is only relevant if we inherit 100 genes.

You are more expert than I am. So, hopefully, with this correction on the flawed math, you can answer the question.

[arkaig]

I complain too much, so I deleted my previous comment here. Only the ambiguity combined with the inexactness of the title falls short of your otherwise excellent work! I look forward to future installments, in this vein, or more on-topic, or otherwise. Thanks!

[newcivilisation]

Thank you! First time I am hearing this!