DNA: The Little Thread of Life

That little thread of life with the big name - Deoxyribonucleic Acid (DNA) - is something I have known a little about for a long time. After reading two books on it, purchasing three spit tests, and trolling the interwebs I now know a little bit more.

This is what I already knew from being marketing director for a genetic testing lab.  First, what the 23 in 23 and Me is.  Do you know? The number of pairs of chromosomes at the center of most living human cells.  Chromosomes carry genetic information in the form of genes.  I once told a boss that he should have kids someday because there’s good things going on in his genes.  Not his jeans!

The other thing I knew about DNA was it told me where my ancestors were from.  As a lifelong genealogist, I was a beta tester for the Ancestry DNA spit test.  However, my family tree had far more information than I received.  Still, my info helps test takers who have not yet researched their family trees!

So, what did I learn?  There are four kinds of DNA that are useful for genealogists.  Let’s review the basics I discovered from Emily Aluchino in Genetic Genealogy.

1. Y-DNA

Y-DNA measures the male line in a family from father to son. My father got it from his father who got it from his father.  How much did I get!?  Nada!  This is because women don’t have the Y chromosome! We have 2 Xs instead. I have 3 exes but that has nothing to do with DNA.  (Wink!)

I purchased a Y-DNA kit from Family Tree DNA for my son Brad for a one name study. This is where they research only one surname, working to find the origins and all descendants.  Can you see the DNA transfer in his 4 generations!?

2. Mitochondrial DNA

Mitochondrial DNA traces the mother’s line from mother to child.  Notice I didn’t say mother to daughter?  That’s because it passes to all her children.  But only her daughters pass it on to their children. My grandmother Gertrude got it from her mother Eunice and passed it to her daughter Pat.  But great-great grandma Ella is Gertrude’s father’s mother, so that grandma passed it only her son where it stopped.

3. Autosomal DNA

 

Autosomal is DNA that everyone has and everyone shares no matter their sex. My grandma Gertrude got some from her father, her grandfather, and her great grandmother – Gunhild the Norwegian.  I was surprised to discover that just like my grandma, Gertrude’s grandfather became deaf as an adult.   We always thought a disease caused it, but now we know it was genetic.

4. X-Chromosomal

While all DNA research is new, the X-chromosomal is the newest, so your DNA lab may not provide the test.  Everyone has some of the X-chromosome, but do you know who will have more – the brother or the sister?  Blain Bettinger, in Genetic Genealogy in Practice, tells us the sister gets about a 1/3 more than her brother.

How much DNA do we inherit?  100% of all that we have!  And 50% from each parent!  As I learned from Christa Cowan, the Barefoot Genealogist on YouTube, it is random, so you never know what you’re going to get - just like in a bowl of fish soup or cioppino. 

My father and mother loved making cioppino.  And each would add the kinds of seafood they like.  It’s like mixing all their DNA together in one gene pool.  I get my DNA from each of my parents, but it could be a different 50% from each parent than what my sister gets.  Sometimes you get the muscles and sometimes you get the shrimp. (Wink!)

So, how many ancestors make up our gene pool?  In 10 generations, like back to King George during our American Revolution, we have 1,024 ancestors based on simple math. Two parents, 4 grandparents, 8 great grandparents, and so on.  But hold on! Some of them could be related (for example, a set of 2^nd cousins marry), so you may not have that many. 

If we go back 40 generations to Charlemagne, the math would equal about 2,000 times more people than who were alive at that time.  What does that say for us descendants today?  We are all related! Smile at the next person you see because they could be your 9th (or closer) cousin!

We can even prove that with my favorite part of genetic genealogy - the haplogroup - which looks at the Most Recent Common Ancestor (MRCA) from centuries ago! For example, the Y-DNA haplogroup starts at A  in which we all share the same base DNA.  Whenever there is a small variation in how the DNA patterns repeat adds a number to the letter like A1.  When there is a large variation called a mutation, the letter changes, like B. 

The R1 MRCA is from Southeastern Asia. And R-M2 MRCA is European. When getting more into the weeds and closer in time, the R-M269 haplogroup matches many of Mayflower Pilgrims based on their descendants.  It’s amazing how DNA led me to nine Mayflower Pilgrims that I have now confirmed by paper research!  Information that I wouldn’t have known if I hadn’t understood facts about that little thread of life!

Click the link to watch the video!