DNA and something called Phasing – 1 Parent

Had this question yesterday, “I uploaded my fathers raw data to GEDmatch. Now how do we do the phasing if I don’t have my mothers DNA?”

Phasing “is the process of trying to determine which DNA came from the mother, and which came from the father. The term is usually applied to types of DNA that recombine, such as autosomal DNA or the X-chromosome. The benefit of phasing is being able to identify which ancestor a segment was inherited from.” http://isogg.org/wiki/Phasing

This particular client’s mother passed away and he has no way of identifying her specific DNA. To get into this more, you might ask, “can’t you just send in some hair from a brush she used?” Why yes you can, IF you can find a hair with a root still attached AND you have blocks of gold lying around the house. This kind of testing is not practical for the average Genealogist.

When you work with DNA you might say generally, “I inherited this much from my dad – say 50% and this much from my mom – say 50%.” Which is kind of sort of a ball park figure. This goes along with what I explained in another blog Why DNA?  My brother, Sister and I all get 50% from our parents. If this were exactly true then we would all be clones of our parents with no perceivable difference. But there are perceivable differences. The differences are all over the place too. So no, you can’t just say I got 50% from each parent and be done with it. Nature has a sense of humor.

So how to tell which parent gave us which parts of our DNA?

Phasing will tell us.

You can not do this currently (April of 2016) at the place where you got your test done, since none of the testing companies offer a phasing tool.

There are two tools available from Genetic Genelogists for Phasing when you have both parents raw data. You can find this information on the ISSOG page on Phasing. http://isogg.org/wiki/Phasing#Phasing_tools

What we want to do is find out which parent we received our DNA from when we only have one parent.

T. Whit Athey, explains how to do phasing when “a family group, consisting of at least three, siblings and at least one parent. The process works best if data for four or more siblings is available.” Phasing the Chromosomes of a Family Group When One Parent is Missing, Journal of Genetic Genealogy, Fall 2010, Vol. 6, Number 1, http://www.jogg.info/62/files/Athey.pdf

We don’t have a whole slew of family members to test to work on this kind of phasing. So, we turn to GEDmatch, https://www.gedmatch.com . If you haven’t already uploaded your raw DNA data to GEDmatch, and at least one parents raw DNA data to GEDmatch, then you will need to do this. Click on upload raw data for your particular company to see what you need to do.

Now that you and your one parent’s raw DNA data is up and available to work with (usually 24-48 hours after initial upload) here is what to do.

Sign in to GEDmatch.
Go to the Analyze your DNA section,
Then to the DNA Raw Data section, and
Click on “Phasing”. This will take you to the “Phased data generator, Data entry form”
Enter the child’s (your) kit number
Enter either the Fathers or Mother’s Kit number
Then Click the link to generate the phased results.

How long did it take? Phasing took 0.45905 seconds.

Child’s Kit: A000001
Father’s Kit: M111111
Processing without mother’s kit.

Paternal kit number: PA000001P1

Maternal kit number: PA000001M1

Your phased Paternal and Maternal files have been generated.

These numbers will appear on your GEDmatch profile page along with other kits you manage. The phased kits will be available for use in one-to-one comparisons immediately. You will have to wait for the usual 24 to 48 before you can compare the new phased Parental kits with other tools offered by GEDmatch.

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Author: grandmasgenesblog

Mags Gaulden “They have been at a great feast of languages and stolen the scraps.” - William Shakespeare. My favorite quote, ever. If I were a color I would be cobalt blue. In tense situations I try to diffuse the tenseness with humor (sometimes this approach works, sometimes not). When it rains I feel calm and restive. When it snows I am an ecstatic child expecting a snow day (living in Canada I am ecstatic often). I am happiest when I am doing something, anything, outdoors. People in my family have had names like Goolie and Nimrod (the last one handed down for generations). I thrive when I am helpful to others. I thrive when I am problem solving. I am a Carolinian at my core and I am deeply rooted in the foothills of the Blue Ridge mountains where I grew-up. If you cut me I would bleed the sound of bluegrass music.

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