Welcome to Ancestral DNA Explained!

 Are you trying to use DNA testing to grow your family tree, or find living relatives?   Having trouble, or just don't know what to do?
   
     LET COUSIN JANICE EXPLAIN IT FOR YOU!!!

      I have a Master's Degree in Genetics from San Diego State University.  Its from 1982, so I can't clone anything.  But, I explain Genetics and how to search using DNA testing.  I got mine from Ancestry, and I'm also on FTDNA and GEDmatch.
      I have some BIG holes in my family tree, and I trying to fill them using DNA testing.  It took me months just to get 3 DNA matches that correspond to people in my tree.  I've taken to asking my DNA matches from Ancestry and FTDNA to get on GEDmatch, which is very technical and scares off a lot of people.  And while emailing with my matches, I found that a whole lot of very bright people don't know how DNA works when it comes to finding ancestors or other relatives.
      So I'm starting this blog to help you all out.  My relatives, my husband's relatives, the relatives of our relatives, and so on, if you need some lessons on DNA, this is what my blog is about.  If I can help you and get some advertisers, feel free to click on them and send me some nickels.

Genealogy: your family tree

You can pay to do your family tree on Ancestry, or use a free site like Family Search, or both, or just do it on paper, and keep it somewhere.  Thats what my grandfather did, before he died in 1967, and lucky for me, I found in 1999 after my grandmother died.

Ok not the greatest, but he put some great info on here!   I have been able to really expand on this branch of my family:

But this is not a formal family tree.  I took some shortcuts here on this diagram, which I used to show my 2nd cousins the basics of this branch, as many of the descendants still live in the same area, and weren't sure how they related.  You can draw little diagrams like this with the basic Paint program that comes with most computers.  All I use are the writing function, rectangles, and lines.

          Basic  Human Genetics 1

You typically have 46 chromosomes in the nuclei of your cells.

         22 Pairs of Autosomes - the non sex chromosomes
           
          2  Sex chromosomes - so called because they determine your gender.


If you have 2 "X" chromosomes, you're a woman.

If you have an "X" and a "Y" chromosome, you're a man.


       These 46 chromosomes are in the nucleus of a cell.  The nucleus is the control center of the cell, and the chromosomes are like the computers that make code to run what the functions of that cell is.


Outside the nucleus, there are other parts, and one of those are the mitochondria.  They also contain their own DNA.

      The DNA in the Mitochondria is called mitochondrial DNA, or mtDNA.  It codes for the making of new mitochondria.

DNA is a very large molecule that makes up most of each chromosome.  When the cells gets ready to divide, the chromosomes coil up into the X shape that you typically see a chromosome depicted as.  Usually though, they are uncoiled so they can be accessed by the cell's machinery to make the code for all the enzymes and other proteins the cell needs.

    

 Basic Human Genetics 2

 

Regular cell division - "Mitosis"
       Say you need a new cell in your Big toe.  A cell's 46 chromosomes will each make copies of themselves, they will line up, and the pairs will be divided, each set going to its own part of the original cell, where they will each form their own nucleus.  The  cell then divides into two, which each new cell having one of the new nuclei.  The new cells will be genetic clones of each other.  So mitosis is the kind of cell division that happens in your TOE, and most other parts of your body.

Sex cell division - "Meiosis"

 Time to propagate the species!

In Women:  In the ovaries, the precursor cell to the eggs divide, but instead of each chromosome making a copy of itself, each of the 22 pairs of autosomal chromosomes lines up with its mate.  So, the Chromosome 1 you got from your father will line up with the Chr 1 you got from your mother.  Then they will "cross-over", meaning that they will exchange pieces with each other. There will be at least one cross-over, sometimes 2  or more, so you end up with a Chromosome 1 that has some from your Dad, then your Mom, then your Dad, etc.   The same goes for all the other Autosomal Chromosomes.  

 X chromosomes in women: there are 2, and they also cross-over.     

Because they divided with out making copies of themselves, the egg only has 23 chromosomes.

Mitochondria: mitochondria also go into the egg.

In Men: In the testes, the precursor to the sperm  does the same lining up and crossing over for the 22 autosomes

X and Y chromosomes in men:  because they don't match, the X and the Y don't cross-over in men.  They do hold onto each other at one end during this process though, which I think is kind of sweet.

Mitochondria: no mitochondria go into the sperm.

Sperm + Egg = Baby!!  well not most of the time. Either the egg is not there at the right time, or the sperm, or if you get fertilization the uterus is often not receptive to implantation, or something went wrong in meiosis or...but that's why they call it "The miracle of life"!

Family Math

How  you relate to your primary relatives:

Your mom:  You got 23 chromosomes from your mom.  22 autosomes and 1 X chromosome. You also got your mitochiondria, therefore your mtDNA, from your mom.   You are 1 generation separated from your mom.

Your dad: You got 23 chromosomes from your dad.  If you are a man, you got 22 autosomes and your Y chromosome from your dad.   If you are a woman, you got 22 chromosomes and your second X chromosome from your Dad. You are 1 generation removed from your mom.

Important concept here: If you are a woman, the X chromosome you got from your dad did NOT cross-over in him.  It is a nearly exact copy of the chromosome that your paternal grandmother passed to your dad.  It is a cross-over hybrid of your great grandfather's and your great grandfather's X chromosome.  LIke a little time capsule, but in DNA,

Your siblings: Cross-overs happen every time a sperm or an egg is made, but they are different every time.   You may get the tip of your grandfather's chromosome 1, while your brother got the tip of your grandmother's.  On average, full siblings share 1/2, or 50%, of their DNA.

Family Math 2

 How do you like these Family Math diagrams I made?  I did them for a teacher, so she could hook the youth of our country into genealogy!!

   Actually, I remember growing up with a lot of 1st cousins and 2nd cousins around, and the ones in between I never could understand.

DNA you get from your grandparents:

If you are a woman:  You got around 1/4 of your autosomal DNA from your paternal grandfather. Same for your other 3 grandparents. You did NOT get any of the DNA on your X chromosomes from your paternal grandfather.  This can be  helpful when you are looking at your X-chromosome matches on GEDmatch.  If you have an X match, its not from your paternal grandfather's side.   One of your X chromosomes came directly from your paternal grandmother, and the other is a cross-ove rmix of your maternal grandparents.

If you are a man: You got around 1/4 of your autosomal DNA from each of your grandparents.  You got your Y chromosome from your paternal grandfather.  You got your X chromosome from your mother, and it is a cross-over mix of your maternal grandparents' X chromosomes.  Anyone you is an X match to you, it is on your mother's side.

Basic Family Tree

Okay you've started on your family tree. You have the names of your cousins. aunts, uncles, grandparents, even some great-grandparents that you know came from Finland (where they love genealogy btw).    The convention for drawing a family tree are fathers on the left, mothers on the right.  A line directly connecting 2 people is a marriage or other kind of union.  Lines going down connect the children to the parents,  If there are more than one child, the line goes down to a horizontal bar, and lines descend from it to the children.

         You are the "you" in this family tree.  You know your paternal grandfather was born in Finland.  Your mother's parents, you know her father was a Polish Jew and her mother was part Hungarian.  But your Paternal Grandmother Susan, nobody knows anything about her background.

         Now lets go get DNA tested.  You buy the kit, swab your mouth or spit into a tube, send it in, WAIT 4 to 8 weeks to get the results back.

         Say you get these results:

          20% Finnish

          15% Ashkenazi Jewish

          15% East European

          10% Irish

          10% Native American

           9% Scandinavian

           8% Italy/Greece

           7% Iberian

           6% Great Britain

Hey, grandmother Susan might have been Native American.