DNA relatives/23andMe

Question

On her DNA relatives page (23andMe) my granddaughter has far more relatives on ʻFatherʻs Sideʻ.  I wonder why this is so. Her father is Mexican, he  shows ʻNative American/Asian 80% and the rest European. This is not a surprise. Her mother is Irish/English/European (plenty of sources support the DNA results).

Are there more connections from a more cohesive population?

Any ideas?

Answer 1

If everything was equal, yes you should have very similar numbers of matches on both sides, but they usually aren't.  I can think of a few factors that would skew the counts:

• Perhaps the biggest one - much larger ancestral families on one side, especially if they are 4 to 6 generations back.  A very large family way back will have many many more descendants, than small or one-child families.
• Some cultures (or mini-cultures or groups) or ethnicities are not as interested in DNA testing.  If they don't test, you can't match!  There's not much you can do about it, except hope the groups of peoples you need 'catch the DNA bug'.
• People tend to take the same DNA tests as their friends or as others in their culture or grouping.  It's possible that more people on the Mexican side were more attracted to 23&Me than other testing companies.  It's possible that if you were to test with AncestryDNA or other company, you might find the very opposite, that many on the mother's side chose AncestryDNA or some other company.  Recently, because of a special promotion at MyHeritage I uploaded my DNA there, and was very surprised at the much larger set of Scandinavian matches I suddenly had!  Apparently, MyHeritage has grabbed a large market share of the Scandinavian market.  In other words, the 'fish in every pool' principle applies, because you can't predict where others will test.  Try uploading to GEDmatch, MyHeritage, and FTDNA, and see if you don't get more results.

There may be other factors too, but I hope this gives you a few ideas. 

Comments

Those all sound like valid reasons to me. I had not considered family size, especially a couple of generations back. Just looking at her parents - mother has one brother (with no descendants) father has five brothers who have many descendants; the odds are in fatherʻs side immediately. The other suggestions, too, are probably a large part of the issue.

I, personally, have 2 brothers, and several close cousins on 23&Me, but my husband (same Eng/Irish etc) has none. So, that likely points to ʻmini-culturesʻ and that his relatives are on the east coast and mine on the west, and have different friends and cultures.

Thanks, Rob, you helped me see some reasons.

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Endogamy can also contribute to this.  Since the whole population is intertwined, they're more genetically similar overall and therefore show up as closer matches than they may actually be, so you get more matches overall.  

I have a perfect storm of this on my maternal grandfather's side... very large families and an isolated population with a lot of intermarriages.  (Current working hypothesis:  if you're related to anyone from West Virginia, you're related to *everyone* from West Virginia.)

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My mother's family is from Lithuania (her mother's parent's side) and Slovakia (her father's parent's) side.  My DNA matches with my mother's family are a fraction of those with my father.

I persisted and eventually had a lengthy discussion with a man in Prague whose daughter was a match for me.  He was very helpful and knowledgable.  He told me that the demographics of much of central and eastern Europe is of a poorer population that likely would never even do DNA tests and if they did they may not use the same services we use in the US.    

It would be so very helpful if there were more standard and common DNA testing services that allowed for consistent and extensive results.  GEDMATCH is one thing, but common testing would be so much better.

BTW, others have probably noticed that their DNA results vary by the service they use.  I found specific DNA matches to the little town of Jakubany, Slovakia in 23andme and no other service brought me to that point.  I discovered over 300 years of records that helped develop generations for my Slovakian family.  I have had zero luck with Lithuania, but great luck on most lines of my father from Germany and England (mostly) to the colonies in the very early 1600's to 1700's.  Ancestry.com does not even recognize those migration patterns in my DNA, but does in my siblings.  

In Ancestry I have several Lithuanian matches and very few Slovakian matches.  But it appears no one in my extended family has been able to figure out our roots in Lithuania YET.  It has been helpful to do one name studies with in my tree (Jecewicz and Gregelevich with way too many variantes).  I have been able to connect several families and can identify how I match with a few of the Lithuanian cousins I have.  A few recent breakthroughs for the recent past (1880's to mid 1900's).  I can not even find any immigration or passenger manifests that I can idenify as my specific family, but they are helpful with the one name efforts.

Laurie