Archives

A Web Site with Tools for Y and other DNA analysis

Apr19

There is a wonderful site at http://www.y-str.org with many good tools for Y DNA and autosomal DNA that run as programs on your PC plus a cool ISOGG Y tree add-on for the Chrome browser. My specific interest at the moment is figuring out which Y SNPs are already tested by 23andme so as not to test them again at FamilyTreeDNA since my Dad has kits at both places. I blogged about how to do that manually back in February, but now there is a program that will do that for you. However it took me a while to figure out how to do what I wanted from the instructions given, so I will do a step-by-step tutorial in this post in order to remember what I did.

BrowseMenuFirst download your raw data from 23andme by going to the “Browse Raw Data” Page which is listed in the menu that appears under your name on the top right. Then on the raw data page click on “Download” in the second top bar on the right hand side. This takes you to a page with various warnings and requires that you reenter your password as well as the answer to your secret question before it starts the download.

Save the download file somewhere that makes sense for you. I have a folder called RawData in the folder DNA that I use. Once the raw data file is downloaded, you will need to unzip it before using it with the various tools. To unzip in windows all you need to do is open a file explorer window (a manila envelope is the icon) and then right click on the file name to get a little menu that includes “extract all” which is the one to click.

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Figuring out a DNA relative’s shared DNA with 23andme’s “Countries of Ancestry”

Mar31

Maybe you have had great luck with people responding to your shares on 23andme but most of us have at best 30% of our share requests accepted (of 1800 DNA relatives my Dad has 338 shares and 40 introduction accepted so just under a 20% acceptance rate). This is especially frustrating when someone is clearly a close relative and does not respond. Of course some of the reason for the lack of response is that the default setting on 23andme is to not send emails when there are messages in the inbox. Fortunately the occasional email from 23andme about new relatives or news does get some of them to log in and see the invites. I always get several acceptances from old shares after one of those broadcast emails.

Yes I can hear those of you who have tested at familytree DNA laughing and say well we can see the shared DNA. But you also may never hear back from some of the most promising leads who do not have much of a tree posted and more importantly you cannot compare people you match with each other which we can do with our shares. There are pluses and minuses to each testing company.

Below are a few of my closest non accepting DNA relatives. S M is public and accepted contact but not sharing. G S is public and responded to a message asking if he was related to my S family from Etne with a no, but has not shared. I made an error on the 3rd introduction to one relative and now can no longer contact them, at least from this account.

Some close DNA Relatives

So for those of us using 23andme I will use these matches as a case study on how to find the DNA segments where they match my Dad using “Countries of Ancestry.” This only works if your relative has entered the countries of origin for their parents and grandparents.

First a little known trick, you can download a CSV of all your DNA relatives by clicking the Download button on the top right of the page when on the DNA relatives page.

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Genealogy books, family histories, and more useful books online, digitized

Mar15

When I was working on a cousin’s colonial ancestry, googling an ancestor’s name* would often find a book digitized and online at google, for example, a local history of Stamford, CT. Recently I saw a post about the genealogically related books digitized by familysearch which said “There are many thousands of historical and genealogical books available to read online. They are indexed so I was able to find old towns where ancestors lived, genealogies of families …”

In short order I found a book at familysearch.org about Norwegians in Brooklyn that listed my granddad and both sets of my great grandparents who lived there. The details of that are posted here on my family history site.

MunsonInstituteAfter I excitedly announced this on one of my favorite mailing lists, others chimed in with more online book resources. So with permission, I am including June Byrne’s list of these and tips on using them.

*n.b. when googling a name, put it in quotes to get an exact match, e.g. “Lawrence J. Munson”

The rest of this post is adapted from a write-up by June C. Byrne.

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Getting all the in common with (ICW) matches at 23andme

Mar14

The DNAgedcom website has a wonderful feature whereby you can download the overlapping segment data for one of your matches with all your other matches at 23andme. Since it will include you in the CSV file, you can quickly see if you and your share both match another person at the same spot (called triangulation by genetic genealogists).

Here is a sample of that type of match from the resulting sorted spreadsheet for an adopted close DNA relative I am working with (names of non-family removed for privacy):

Comparison Chr Start point End point Genetic distance # SNPs
Adoptee CR vs 1st cousin GP
 5 113000000 124000000 11.8 2217
Adoptee CR vs me
 5 114000000 121000000 7.2 1401
Adoptee CR vs Dad 5 114000000 124000000 11.2 2038
Adoptee CR vs my brother 5 114000000 124000000 11.7 2112
Adoptee CR vs SS 5 115000000 123000000 8.9 1602
Adoptee CR vs EJ 5 116000000 123000000 6.8 1391
Adoptee CR vs AH 5 116000000 123000000 7.8 1482
Adoptee CR vs AC 5 117000000 124000000 7.4 1421

The four other matches are a bit small but the one with SS is mildly promising; so to be absolutely sure it is a triangulation I have to compare SS back to my family members. Here is how that looks in the 23andme chromosome browser (which can do three at a time with any of your shares):

SSvsUs
And we see that the overlap with me is just a little bit too small to show up, less than the 23andme threshold, but my Dad and brother are a triangulation.

So read on to find out how to use this download feature at DNAgedcom.com.

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How can the X chromosome help with maternal versus paternal?

Mar11

“My half-sister and I have been tested to confirm half-siblings. Is there any way to know which parent we share” – this is a rephrasing of a question posed by a woman on the DNA-ADOPTION mailing list at Yahoo. A discussion of the problems of mtDNA ensued. Because the mtDNA haplogroups go back thousands of years, a match is no guarantee of a recent ancestor like a mother. So that information can only rule out the maternal side if there is a mismatch. Deeper mtDNA can get closer but still this is not certain territory yet.

However since they are both female, the X chromosome can give a definitive answer because their father(s) would pass his only X chromosome unchanged to each of them. A man has one X and one Y chromosome and a woman has two X chromosomes. Whether the father passes an X or a Y to his child determines its sex, but since neither is recombined the child gets exactly the same X or Y chromosome as the dad has.

Since a girl has two X chromosomes, one is from her dad. Two sisters with the same dad will therefore ALWAYS match on the entire X chromosome since they have one complete X in common.  If the mothers are related, then some of their X will be a full match as well. So let’s look at some X chromosome comparisons at GEDmatch:

Two Half Sisters X comparison at Gedmatch

This is what the two half sisters from the question look like. The blue indicates that there is a match, the colors above it whether on one chromosome (yellow) or both (green), while red is no match. A few small errors can creep in when processing DNA so an occasional little red line can be from an error. Click the read more once you have decided if they have the same mother or the same father.

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