Sunday, October 19, 2014

My Most Bizarre & Misguided Responses from My 23andMe & Family Tree DNA Matches

Well folks, a whole lot of people are now getting their DNA tested for genealogy purposes. That's great!!! But unfortunately, as I attempt to contact my DNA Relatives, it is ever more clear to me from the responses that I've received that many of them don't have a clue what sharing DNA means in terms of genealogy!

Here are some of the typical and frequently bizarre responses I have received:

1)  "We don't share the same haplogroup, so we cannot be related," and conversely, 'We share the same haplogroup, so we must be related".
Haplogroups are incredibly interesting! They allow you to explore your deepest ancient roots-- but usually have very little to do with one's genealogy over the last 500 years.

It is entirely possible to NOT share haplogroups, and yet share ancestors & DNA.  I certainly have first cousins who do not have the same maternal haplogroup as I do--because we all had different mothers!

Paternal Y haplogroups can be helpful in a more recent genealogical sense if you are researching a very common surname in a male line, such as SMITH or JONES. For instance, I have established through my brother's 23andMe test that my male HUBER line has the Y DNA haplogroup i1b2 (now known as i2a2a).  That knowledge could help me eliminate other male HUBERs in colonial Pennsylvania as possible ancestors. There were A LOT of different HUBER families  in colonial Pennsylvania.

2) "I don't see my surnames or locations in your list or on your family tree, so we must not be related" 
The people making this statement usually are matching at 3rd-4th cousin level, but have only listed 2-4 surnames.  They are not taking into consideration that the shared surname & ancestor will most likely be found back 4-5 generations.

I frequently encounter people who don't have a clue about their own genealogy beyond their grandparents. However, most genealogists worth their salt can take the names of someone's grandparents  and can usually find out much more about that person's ancestry.

And then there is the sticky issue of illegitimacy, or a "non-paternal event".

As for locations:  it never fails to amaze me how much people moved around,  from the very beginnings of our country to the present day.  We are all a long way from our original home. One should not discount a DNA match just because the shared ancestor or location is not immediately obvious.

3) "I match YOU, but don't match your brother, sister, etc so we must not be related" and conversely, "You match ME,  but don't match my brother, sister, etc so we must not be related".
Because of completely random nature of recombination,  it is entirely possible for one sibling from a family to match a  3rd-5th cousin who does not match anyone else in the family.    In my own case, my brother & I have both been tested;  in our matches with 3rd-5th cousins, I have found that he may possibly share more DNA than I do with a cousin; the same amount of DNA;  less DNA or no DNA with a cousin.  He can also share on different chromosomal locations than I do with a cousin.

We both have several known 4th cousins with whom we share absolutely no DNA.

Shared DNA amounts decrease exponentially with each recombination, i.e. each generation. Here is a very good chart from 23andMe website, showing the percentages.

4) X Chromosome confusion: "We must match on the mtDNA line! Here's my mother's mother's mother's mother...."
I must admit, shamefacedly, that I was clueless about what the X chromosome means for genealogical research until I was educated by one of my DNA cousins on 23andMe this past summer.

Now I am totally fascinated!  I filled out a fan chart (see previous post) showing who those X chromosome carrying ancestors are in my family tree!! Woo Hoo!! This knowledge can really narrow down the field of possible shared ancestors for those matching on Chromosome X!!

So I contacted all of my X matches on 23andMe, thrilled with the prospect of maybe finding some common ancestors--only to discover that A LOT of them believe that the X Chromosome is the same thing as mitochondrial DNA (mtDNA)--which is only partially true. For both men & women, the mitochondrial line will be included with the X carrying ancestors--but they are not the ONLY ancestors that carry the X chromosome.

As you all probably know,  Men receive one X chromosome from their mothers, and one Y chromosome from their fathers.

Women receive two X chromosomes, one from their mothers, and the other from their fathers--which is actually the X chromosome of his mother, their paternal grandmother.

So certain males in your family tree CAN be X chromosome carriers as well as the females. There is a specific pattern of descendancy. See my previous post.  Or this blog post "X Marks the Spot" by Roberta Estes, which has the color-coded fan charts for both men and woman, created by Blaine Bettinger. These clearly show the pattern of descent for your X Chromosomes.

Another thing that most people don't seem to understand is that a match on the X chromosome is definite & specific.  If I match you on the X chromosome, and I send you a chart of my possible X chromosome ancestors, then somewhere, somehow  you MUST be related to one of those ancestors on the chart. They are the ONLY possibilities in my entire family tree. You may be descended from a child or grandchild of one of the individuals on the chart, but that individual will always end up being our "most recent common ancestor" MRCA.

One of my X matching DNA cousins latched onto the surname of one of my male X carrying ancestors, WILLIAM F MILLER b 1814, and claimed that our shared ancestor had to be a female Miller from her family tree who was born 1697.

I tried to explain that no MILLERs previous to WILLIAM b 1814 would qualify as an X chromosome ancestor, because WILLIAM received only a Y chromosome from the MILLER side of the family.  He received his X chromosome from his mother, LUCY ANN WOODSON.

However, if one of WILLIAM F MILLER's children or grandchildren born in the 1850s  were her direct ancestor, then that could work, because our "most common shared ancestor" MRCA could still be WILLIAM F MILLER. But it the child/grandchild were female, there is a 50/50 chance our MRCA could also be WILLIAM F MILLER's wife, ELIZABETH T MOSELEY.

She did not believe me, and continues to think we are related through the Miller born 1697.

This is complicated stuff!

5) "Why are you contacting me?"
This is a surprising response I sometimes get to emails from Family Tree DNA website,  from people who have posted their email addresses, genealogical information and other  info on their profiles.

6) "Hey! We are DNA cousins! I want everything you have on your family! (this from a 23andMe profile with no name on it)"
This is a problem exclusive to the 23andMe website, and it's one of my biggest pet peeves. I have about a dozen DNA cousins on my DNA Relatives list who have never put a name (nickname, pseudonym) on their profile.

If there is no name on a 23andMe profile, the person owning the profile can't be invited to share genomes.  I have had several of these no-name people contact me and request "everything I have."

At first I tactfully request that they add a name/nickname to their profile and why.  Lately I have been adding, "Until you put a name or nickname on your profile, I will not share anything with you."  Harsh, I know--but I think it's incredibly rude to request all my personal information and years of research--while remaining totally anonymous.

I'm sure that some people think that having no name on their 23andMe profile will somehow protect their privacy, but all that it does is make that person completely inaccessible.  No one can find them, no one can invite them.  If that is their intention, then fine.  Just don't expect others to "share everything"!

(23andMe really needs to change this on their website,  and require that every person who gets tested puts some kind of name, nickname or pseudonym on their profile.)

7) "23andMe says we share DNA and are related, but I don't believe it. We don't live in same state, same country, aren't same ethnicity,  etc, etc, and besides no one in my family has ever heard of you or your family!"
Folks, if you share any amount of DNA with someone else,  then you are definitely related.  Somehow, some way.  Matches sharing less than 0.20% may be fairly impossible to document. But as a friend once said, so eloquently: "DNA don't lie"!

Have a great day!


© Betty Tartas  2014


Amanda (the librarian) said...

Great post Betty!

Karen's Adventures in Sewing Land said...

Really good post - I admit I am quite lost when it comes to DNA genealogy, so this is very helpful.