DNA and GENEALOGY

I've been reading up on DNA and how researchers use it to help them learn about where a person's ancestors came from and what migration routes they might have taken over thousands and tens of thousands of years. 

The most interesting thing I have learned so far is about mitochondrial DNA or mDNA.  DNA, as I'm sure you know, is a coded message, in the form of chemicals attached to each other, that tell the cells which proteins to make. Every cell nucleaus contains a full set of DNA.  Half comes from the father, half from the mother.  But there is another type of DNA.  This is called mitochondrial DNA or mDNA and it exists in the liquid cytoplasm surrounding the nucleus of the cells of the body.  This type of DNA comes only from the mother and it has to do with the size of eggs compared to the size of sperm. During fertlization, the small amount of mDNA in the tiny sperm is destroyed, while the amount of mDNA in the larger egg is much higher.  Thus, you inherit MDNA only from your mother. 

Scientists use mDNA to trace matrilineal lines.  And, although all humans have mDNA in the cytoplasm of their cells, only females can pass on that type of DNA.  So my great great great grandmother, Anna Maria Elizabeth Gerdemann, passed on her mDNA to my great great grandmother, Maria Bernadina Wrocklage, who passed it on to my great grandmother, Mary Gertrude Frecker, who passed it on to my grandmother, Mary Bernadine Schulien, who passed it on to my mother, Frances Joan Brennan, who passed it on to me.  I, in turn, have passed it on to my daughter, and she to her daughters. 

Just for fun, I decided over the weekend to see how many descendants of my great great great (or 3rd great) grandmother are living with her mDNA.  I was quite shocked that there may be only two lines remaining that carry her mDNA - mine and that of one other family.  And this is quite remarkable, as I have many female ancestors among the descendants of Anna Maria Elizabeth Gerdemann.  I will only report the female descendants below.  Keep in mind there are also many male descendants, but they cannot pass on the mDNA.

Anna Maria Elizabeth (1801-1840) had three daughters.  One never married.  One had two daughters, two granddaughters, and one great granddaughter.  The female line stops after that.  The third daughter was my great great grandmother, Maria Bernadina Wrocklage Frecker.  She had three daughters.  One of those daughters  had three daughters herself.  Of those three daughters, one became a nun, one died young, and the third had one daughter.  The line of daughters ends at that point. The second daughter of Maria Bernadina had three daughters, all of whom had only sons, so the line of women stops there.  The third daughter of Maria Bernadina is Mary Gertrude Frecker, my great grandmother.  She, too had three daughters.  One had no children, and another had one daughter who is still living.  This daughter has four of her own daughters, and they produced several granddaughters who are all living.  The third daughter of Mary Gertrude was my grandmother, Mary Bernadine. She also had three daughters.  One never married and one had only sons.  The third daughter, my mother, had one daughter - me.  I have one daughter and two granddaughters.

So even though Anna Maria Elizabeth had a large family, including three daughters, 5 granddaughters, 11 great granddaughters,  today there are only a handful of women and girls who have passed on or will be able to pass on her mDNA.

While this tidbit of genealogical information may not seem all that exciting or even relevant, it was very interesting to me.  In a time when sons are still valued more than daughters, at least in many parts of the world, and in a time when the male surname is still passed on much more than the female surname (though that seems to be changing a bit) it is comforting to note that some things only women can pass on - and one of thse things is their mDNA, which gives researchers some of their best clues as to where our ancestors came from.  I think that's pretty nifty.