Mitochondrial DNA: your maternal line, its not as close as you think

Question

I was an early DNA tester: the Beatty DNA project is one of the biggest (and oldest) and has a couple of DNA scientists who've taken our project to extremes.  After I signed up for a Y test, I decided to get the MtDNA also.  So many years ago I had very few hits but I seem to get a new one every few months and I must have 30 or 40 matches with zero distance matches.  In other words, a perfect match on all 16,569 markers.

Just yesterday a new tester who is a zero match to me emailed and asked if I had a tree he could look at.  It turns out that his family is huge into genealogy (they have been for nearly two centuries) and they have the family tree well plotted out to the 17th century.  He said that he has a good paper trail on his maternal line back to England in the last 1600's.  And so he's wondering, how is his maternal line Swedish?

I have wondered the same question - my line is for sure Swedish - maternal Grandma was a first generation American and both of her parents came from Sweden.  Sweden has exported a lot of people over the last dozen centuries but hasn't had many migrants until recent days.  Yes, I have 0 distance matches in Ireland, England, northern Germany, and some in the Baltic States.  I've often wondered if this MtDNA line goes back to Viking times?  

I checked FtDNA's page on MtDNA and they claim that if you have a 0 distance match, there is a 50% chance that your most recent common ancestor (MCRA) is within the past 5 generations, or about 125 years.  I have a hard paper trail on my maternal line (yay for Swedish records!) back 7 generations and 253 years.  Hmmmm.... doesn't sound right.  Well, I must be in the other 50% right?  What about the matches in other countries?  I suppose Swedish immigration during the 1800's to England because of famine refugees but to Germany, to Latvia?

And so, I began to read up on MtDNA and I found this article and it confirmed what I've long suspected.  Your MtDNA most recent mutation could be one generation, or it could be 2,000, 3,000, or even 5,000 years past.

Concepts – Genetic Distance

It is a fascinating article and I highly recommend giving it a read.  It covers both YDNA and Mitochondrial.  The author confirms my suspicions, that my matches in Latvia and Ireland may be remnants of old Viking colonies.

Answer 1

I was just contacted by a mtDNA match to my mom who's from Saudi Arabia.  Haven't had a chance to look at details yet but I'll be curious to see just how close a match it is.  My guess is that it's pretty far back, given what we know of our history.  (On the flip side, we have a cousin at 0 distance who I was able to connect to through my 5th great grandmother.)

Comments

If the mutation rate for the MtDNA is every 2,000 years for your set of genes then everyone from your Grandma, to your 5x great, to your 25x great will all be matches! 

Answer 2

Descent is very random.  Most lines die out, quickly or slowly, while a minority proliferate.

Those big haplogroup trees are very misleading,  They show the ancestry of the lucky survivors, but they don't show all the extinct lines.

Trying to predict earlier geographical distributions from later distributions is virtually impossible.  There needn't be much relation between the area where a type proliferates and the place where it originated.  The noise swamps the signal, so statistics are inapplicable.

This is obvious when we look at America.  But we know about the settlement of America, so we can discount it.  But that wasn't the first big dislocation of population.

So we can easily have a scenario where a mutation happens in say Italy.  Centuries later, there are several surviving lines of descent, with identical DNA, but scattered a bit by then.  Not still going to each other's weddings.

Somehow, one line gets to Sweden.  Don't ask how - we're talking about a single person, so anything can happen.  The way the haplogroup people talk, if a variant from A turns up at B, it must have been carried by a whole boatload of invaders, if not a fleet.  But it only needs one person.  Most of the other people on the boat carried lines that are now extinct.

By the random luck of the draw, the lady who fetches up in Sweden happens to have lots of living mt-descendants.

Meanwhile, the other lines fizzle out.  But maybe one line lingers on, carried by a few people in Italy, or Poland or Ireland.  And those people are now puzzling over their Swedish ancestry, when none of their mt-ancestors was ever anywhere near Sweden.

Comments

Loved this answer! 

Answer 3

Hallo, god ettermiddag from Norway where it's a mostly cloudy 16 degrees.

My previous post was deleted without notice.

My apologies for any infringement. I have an advanced degree in biochemistry, have been involved in genetic genealogy since 2003 and, while I'm no authority,  I respectfully state that I know more than the average bear.

Might you at least explain why my post was deleted?

Comments

Wow, in fact the OP, SJ Baty, had significant comment to the thread.

Why was it deleted?

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Your related comments here in:  Is MtDNA good for genealogy purposes?

So good to see you back and commenting, even if "drive-by's"!  I've been wanting to chime in, in support of your last comment in the above thread, haven't gotten around to it yet.  (And I'm envious of your current location!  Been watching this lately.)

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There seems to be a lot of it about.  Perhaps there's been an instruction.

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There's no instruction to delete g2g posts  At most they are hidden and even that is to be used sparingly.

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This thread is weird.

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Well if anything was hidden, it hasn't reappeared.

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It wasn't hidden either. I think,  as Rob pointed out, Edison's comment he made is in the other mtDNA post, not this one.