The DNA of eye color: it’s complicated

Aug25

In high school I learned that blue eyes were a simple recessive gene so two brown-eyed parents could have a blue-eyed child but not vice versa. Recently I discovered that this was wrong. Many genes are involved in eye color and with the subtle variations in eye coloring.

GEDmatch eye color prediction for me

GEDmatch.com eye color prediction for me

So I ran the fun eye color calculator at GEDmatch.com and discovered that it shows many of the SNPs involved in my eye color with the details of what they each do.

I had not realized that blue eyes are caused by the lack of (brown) melanin, so really are no color. Blue happens the same way the color of the sky does: light is bounced around in a way that appears blue according to the wikipedia article on eye color. Maybe that is why my eyes appear greenish when I wear certain green shirts and turquoise when I wear those color shirts.

If the two blue-eyed parents have their lack of eye color melanin caused by different genes then they could have a brown-eyed child. I happen to know a brown-eyed child of green and blue-eyed parents (and she looks just like her Dad so not what you are thinking). This case got me curious about how that could happen. So I googled around and found this wonderful article that explains it: http://genetics.thetech.org/how-blue-eyed-parents-can-have-brown-eyed-children

Here is my attempt to simplify the ghist of that article:

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In defense of Ancestry.com’s DNA offering

Aug23

The recent good sales prices got to me, so I broke down and tested my brother with the Ancestry.com DNA test. I had held off testing there, not because of the low opinion of their DNA tools held by serious genetic genealogists, but because my ancestors emigrated to the USA so recently that I doubted whether I would have many useful matches in a database that is 99% American.

So why do the serious genetic genealogists complain? My DNA cousin and blogger Kelly Wheaton  on the DNA-NEWBIE yahoo list described ancestry’s offering as “a dumbed down product on steroids;” which really says it well.

ShipleyAncestryDNAsmllShe went on to say, “What Ancestry.com DNA testing does better than anywhere else for people with a decent sized tree (1,000 people or more), and who are American or Canadian, is make matches for you. If you have a DNA match and a tree match it does the work for you. Although these suggested matches may not be accurate in terms of who the ancestors in common are for two people who have multiple relationships, for most they do a fine job.” I completely agree with her.

By the way, the serious genetic genealogists do not like it because you cannot see where the DNA segment match is and thus triangulate with another cousin to prove that this is the right common ancestor. You have to load the raw data from ancestry to GEDmatch in order to look at the segment overlaps and not all your matches at ancestry will do this. But you have to give Ancestry.com credit for good marketing and for making it easy for folk who are not interested in doing the hard work to prove these relationships.
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My presentation on GEDmatch Tools is this Thursday in Carlsbad, CA

Aug19

If you live anywhere in the San Diego area, you might enjoy hearing me talk about the tools at GEDmatch this Thursday evening, August 21, at 6:30 to the DNA Interest Group of the North San Diego County Genealogical Society (known as DIGG  – click this link for location details) .  I will link to the presentation in the comments here by Thursday. Instead of powerpoint, I am using a cool online HTML 5 tool at slides.com to create the presentation. Here is one of the images I made for the talk.

Sample Admix MDLP World-22 Calculator

Sample Admix MDLP World-22 Calculator

In the left image, the pygmy is actually the smaller red slice and Sub-Saharan the larger – can you tell the colors apart? I cannot.

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How many ancestors do we all really have?

Aug16

In a post back in May, I discussed how there were not enough people on the earth in about the year 1000 A.D for all the ancestors we theoretically have.

Recently I found a great Utube video via a facebook post that explains the “how many ancestors” problem brilliantly. So here it is:

One can postulate that everyone alive at about 1000 A.D. in Europe, who has descendants, is the ancestor of every European person today. Therefore we are ALL descended from Charlemagne. I have at least 3 documented lines to him, how many do you have? See this page on my family history site for more.