DNA again

It’s time for another look at DNA. I will attempt a brief and somewhat simplistic description of DNA in the following paragraphs, but you should not take this as a completely accurate definition. For a better description, this is a good place to start: http://dna-explained.com/2012/10/01/4-kinds-of-dna-for-genetic-genealogy/.

DNA gives each cell in our bodies instructions for its function (hair, eye, lung) and characteristics (brown, blue). Most of the DNA in each cell resides in 23 pairs of chromosomes. Chromosome 23 determines our genetic gender. We all get an X Chromosome 23 from our mother. If we get an X Chromosome 23 from our father, we have an XX pair and are female. If we get a Y from our father, we have an XY pair and are male.

Chromosomes 1-22 are called autosomes. Our autosomal DNA is inherited in equal proportions from each of our biological parents. Conversely, we only inherit half of each parent’s autosomal DNA, meaning that half of what they inherited from their parents is passed on to us and half is not. With the exception of some multiple births, each sibling receives a different mix of DNA segments from each parent.

A tiny percentage of our DNA, called mitochondrial DNA, is separate from our chromosomes. Whether sons or daughters, we all have it, but only daughters pass it on to their children.

Aside from our autosomal DNA being divvied up and passed out to children in different combinations with each generation, pieces of DNA are subject to minor changes from time to time through the generations. These mutations help us define different subfamilies in genetic genealogy and human history. Because Y-DNA and mitochondrial DNA are less prone to change than autosomal DNA is, they provide a strong map for all-male and all-female ancestry.

So what kinds of tests are available for DNA?

• Autosomal tests reveal DNA information from all of our ancestral lines, not just our all-female or all-male lines. DNA analysis tools for autosomal tests can show us, by comparing our DNA with the DNA of our matches, what segments of DNA came from different ancestors. The segments can be from Chromosomes 1-22 and I think also from X chromosomes in the Chromosome 23 pair. Autosomal DNA testing is generally useful for common ancestry within the last two centuries or so. DNA test results can be used hand-in-hand with traditional genealogical research to find or confirm what neither alone might be able to determine.
• Mitochondrial DNA tests identify people who share common ancestors on their all-female lines, that is our mothers, their mothers, their mothers, and so on. Because mutations occur only rarely in mitochondrial DNA, these common ancestors might be hundreds or even thousands of years back.
• Y-DNA tests identify people who share common ancestors on their all-male lines. Y-DNA mutations occur seldom enough that these common ancestors can be much further back in time than is likely with autosomal DNA matches.

At the beginning of this year Dee and I tested our DNA with 23andMe. Later in the spring Mom and Dad tested with 23andMe as well. I have previously talked a bit about some resulting discoveries and confirmations. Later in the year, Dee and I tested with AncestryDNA and recently with Family Tree DNA. Each of these companies offers something different.

• 23andMe provides useful DNA tools and has a history of genetic health reports that the FDA suspended for a time but are again permitting.
• Ancestry DNA doesn’t offer DNA analysis tools, but their DNA results are tied into family trees from a very large customer base.
• Family Tree DNA provides DNA tools and offers additional DNA tests for all-male and all-female ancestry.

In general, mitochondrial and Y-DNA tests are more expensive than autosomal tests, but 23andMe recently doubled their price for autosomal testing in conjunction with the inclusion of health-related genetic reports.

With 23andMe’s renewed provision of genetic health reports, they have overhauled their website, consolidating and at least temporarily dropping some of their genealogy-related functions. I have been able to communicate with other testers who share DNA with me and my parents. Some of the DNA shared between one of my parents and other testers was not passed on to me but might well have been passed on to one or more of my siblings.

Dad’s family hasn’t had many close relatives test with 23andMe. One unknown tester shares enough DNA with Dad to be estimated as a first or second cousin. Dad has hundreds of other DNA matches, many of whose identities are known, but they all share less than 1% of their DNA with Dad. Nevertheless, comparing matching DNA segments with others who know something about their ancestry can provide clues for finding common ancestors.

Taking a look at my closest matches, you will notice a few McCalls near the top of the list. Janet McCall manages the testing profiles for several members of her family including two more not shown here. My Grandma Sovereign, born as Marie Fisher, was Betty (Abell) McCall’s first cousin. However, I never knew anything about the McCall family until we connected through 23andMe. Betty’s mother Grace (Dennis) Abell was Marie’s mother Idell’s youngest sister. Mom and Betty are about the same age, but Betty’s grandparents John Dennis and Rachel (Powell) Dennis were Mom’s great grandparents.

You might also notice that Dad’s closest DNA match appears in my list of matches but not all of the DNA shared between Dad and our anonymous cousin was passed to me. Dad shares 6.99% of his DNA with Mr. Anonymous in 17 segments. I received a 4.08% share of common DNA in 12 segments.

I have posted previously about Dad’s fifth cousin, found through 23andMe, who shares a small amount of DNA that came down the line to Dad through Staats Springsteen. That DNA was not passed on to me.

AncestryDNA provides tools to associate people with shared DNA. They don’t reveal the shared DNA segments but they do indicate how much is shared. AncestryDNA also maps the matching testers to their family trees in Ancestry, a definite genealogical benefit. They have also introduced DNA Circles, which shows clusters of people who share common DNA and suggest their common ancestor. I have been assigned to three DNA Circles so far, the John Samuel Dennis Circle, the Rachel Powell Circle, and the James Kidder Circle. The first two circles have four members and consist, of course, of the same members. The James Kidder Circle currently has ten members assigned to it.

AncestryDNA maps out the relationship between DNA matches when they can identify the connection based on our Ancestry family trees. I learned the identity of J.M. from one of his first cousins at a recent visitation for his aunt Merilyn Fisher.

Like 23andMe and AncestryDNA, Family Tree DNA offers autosomal DNA testing that is useful in finding distant cousins who share DNA in any of our chromosomes. Family Tree DNA’s autosomal test is aptly called Family Finder, casting its net wide to find cousins. We found a second cousin from Dee’s Czech family in Family Finder who could then be identified as a recent tester with 23andMe.

In addition to autosomal tests, Family Tree DNA offers mitochondrial and Y-DNA tests. As indicated earlier, these tests are suitable for finding people who share female-line or male-line ancestry far back in history. Our results from these tests have just been reported in the last few days, so I don’t have a good handle on using the resulting information yet.

Dee and I have both been tested at an intermediate level for mitochondrial DNA (mtDNA). She has 1000 matches at that level and I have 830. Again, these matches are people who almost certainly share common ancestors with us somewhere up our all-female ancestral lines. By contrast, autosomal DNA matches can be coincidental by virtue of repeated recombination of segments through the generations.

My Y-DNA results were quite surprising. I have only one match among those who have invested in Y-DNA testing:

Did you notice the next surprise? My sole Y-DNA match is not named Springsteen. Yet we come from the same male line. I imagine that Mr. DePew has been waiting for a Y-DNA match to show up and might be just as surprised as I was.

I am fairly sure that my paper trail for male-line ancestry is valid back at least to Staats Springsteen based on the small amount of DNA Dad apparently inherited from him, so I changed the base line for percentage calculation to five generations. With 93% chance of a common ancestor within twelve generations, that could reach back to a time before surnames were used in our male line. Dutch families on both sides of the Atlantic were commonly known by patronymics in the seventeenth and eighteenth centuries. In my line, Symon Casparse was the son of Caspar Melcherse, who was the son of Melchior Casparse. The surname Springsteen was associated with these families in the new world, but not everyone in those times used a surname at all. Another obvious explanation is that someone in either my family or Mr. DePew’s might not have been the daddy. Nevertheless, we have a big fat question mark. I wish more Springsteen men, preferably in other lines, would have their Y-DNA tested.

This exploration of family history just keeps getting more interesting.