Showing posts with label numbers. Show all posts
Showing posts with label numbers. Show all posts

Tuesday, February 26, 2013

DNA tests - Making sense of percentages

My parents and I have all done DNA testing, at both FamilyTreeDNA and 23andme.

The image below shows my mom's "Ancestry Composition" from 23andme.  Ok, so obviously, mostly European. Got that. But what exactly do these percentages represent? I was trying to make this more clear in my mind as to what the 0.1% signified.



So I started thinking. Mom has a number of percentages that are at 0.1%. In order to make that equal 1 person, I would have to have 1000 ancestors represented in this evaluation.  Then I went looking for how many generations it takes (remember, your number of ancestors in each generation doubles) to get to 1000 ancestors.  The answer? 9.  (I used this website.)

By the time you get to the 9th generation back from you (that is your 7th great-grandparents), you have 1023 unique ancestors. However, it is unlikely that there are no intermarriages and duplicated individuals.  So generally, the 9th generation back gets us 1000 ancestors. That website gives a general birth year of 1680 for this generation. (A previous post at this blog counted the ancestors that I have identified by generation; I have 83 of the 512 in this generation identified.)

So taking mom's percentages, based on 23andme's speculative percentages, out of 1000 ancestors I get the following numbers of people in her ancestry:

466 British and Irish
117 French and German
45 Scandinavian
312 Northern European
42 Iberian
9 Southern European
1 Ashkenazi
5 European
1 Sub-Saharan African
1 East Asian/Native American
1 Unknown



Cool, right? That is a little more...understandable. Concrete. Essentially mom is half Irish/Scottish/English/Welsh. Most of her known ancestors in this group are Irish/Scottish. And she definitely has duplicate ancestors - her paternal grandparents were first cousins (surnames McFEATERS and McCACHREN).


Dad's results:
305 British and Irish
127 French and German
124 Scandinavian
360 Northern European
9 Sardinian
5 Italian
25 Southern European
33 Eastern European
9 European
1 South Asian
1 East Asian/Native American



My results:
409 British and Irish
84 French and German
17 Scandinavian
418 Northern European
11 Iberian
4 Italian
32 Southern European
5 Eastern European
16 European
2 South Asian
1 Unknown


I've got some of these results that I am scratching my head about, but being able to take Dad's results, Mom's results, and my results and compare them, I can see patterns.  Got the Italian from Dad (not surprising, with his Gredler family being in Tirol in Austria, near the Italian border), Iberian from Mom (NO CLUE about this group), and missed some of the markers. I didn't get either one of their East Asian/Native American marker, and I didn't get Mom's Ashkenazi or her sub-Saharan African marker.

Another excitement is that one of the matches at 23andme is someone that I talked genealogy with probably 10 years ago. We know we are cousins and have researched together previously on the McFEATERS and CAMPBELL families in Pennsylvania. So now I have my first paper AND genetic cousin match!!! So exciting!

Sunday, August 19, 2012

By the Numbers

I've been seeing several posts of the last few days regarding the number of ancestors we potentially have up to the 10th generation, and how many we have actually uncovered.


GenerationNumberFound
Parents22
Grandparents44
Great grandparents88
2nd great grandparents1616
3rd great grandparents3229
4th great grandparents6453
5th great grandparents12867
6th great grandparents25670
7th great grandparents51283
Total1022322 (31.5%)

This uses my current genealogy database, but I am pretty sure that it is not ancestors that I am waiting to complete data entry on, but rather collateral relatives.  I am surprised at the percentage: quite a lot of Dad's family is "old New England" and those are the lines that can be traced the furthest. The greatest degree of ancestry that I can trace are seven individuals that are my 19th-great grandparents, born in the 14th century. I haven't looked at those lines in awhile, so I haven't studied them and sourced them to the same extent.

I have my "walls," of course. My MAHAN family in Pennsylvania immigrated in 1819 from northern Ireland. I'm working on figuring out if/how my RICHARDSON family in western New York is related to any of the other New England Richardson families. I've got some western Pennsylvania coal miners that left few records and are difficult line to trace.

Two of my 3rd-great grandparents I actually have some sort of name for, but no data on them. The death record of my 2nd-great grandfather Frank Xaver Gredler gives the names of his parents as Frank Gredler and [--?--] Prutoz. So those names are not included in the numbers. I have had little luck and even less experience trying to get records from Austria, where Frank Xaver Gredler was born.

At least I know how I will be keeping busy!