My Journey Down the DNA Rabbit Hole

The field of consumer DNA research is exploding, with more and more companies popping up all the time, offering different tests and services.  Since I first read about it, I’ve been fascinated by the idea of DNA analysis. As a result, I have spent several hundred dollars pursuing information about my genetic makeup. I’d like to share some of the things I’ve learned.

Over ten years ago, after reading several books and articles on ancestral DNA testing, I had my husband’s Y-chromosome DNA tested. This traces the males in your line (but only the males) back through the generations. I also had our mitochondrial DNA analyzed. Mitochondrial DNA comes from your mother, so this test traces your genetic heritage back through the females (and only the females) in your ancestry.

The results of my husband’s Y-chromosome test were interesting, as he has a haplotype (basically a genetic profile) associated with a group of Bronze Age nomadic herders called the Yamnaya. About 4,000 years ago, the Yamnaya migrated across Europe, reaching all the way to Ireland. With them they brought horses, distinctive pottery styles and burial methods, and very likely the proto Indo-European language that became the basis for all modern European languages. They also introduced their DNA and were very successful at leaving it behind. Indeed, even today 90 percent of men in northwest Ireland carry the R1b1 haplotype of these ancient horsemen.

There are only seven distinct haplotypes of mitochondrial DNA in people of European descent, and both my husband and I tested as having the “Helena” haplotype, common in the British Isles and northwest Europe. Unfortunately neither mitochondrial or Y-chromosome DNA tells you anything about your ancestors who are not in your direct male or female lines. Plus, you will discover you are a “match” to literally dozens of people, so it ends up being fairly meaningless. To really learn about your ancestry, it’s necessary to do autosomal DNA testing, which analyzes the chromosomal profile of your non-sex related chromosomes.

My brother-in-law had his tested by the National Geographic Genome Project. The test showed he was primarily of Western European heritage, with no mention of Irish DNA. But the test did reveal that 3% of his DNA came from the Neanderthals and 1% from the Denisovans, another very ancient group of humans. Not all companies test for this link to ancient peoples. You may be wondering why anyone would care. But the more scientists learn about the Neanderthals, the more they realize how much influence they’ve had on us genetically.

I was perplexed by my brother-in-law’s lack of Irish genetic markers until I learned that each sibling can have a completely different mixture of ethnicities. When my husband’s autosomal DNA test came back, his results were indeed much different. He tested 86% Irish. In fact, he had such distinct Irish DNA markers that Ancestry, which did the test, linked him to likely having ancestors from southwest Ireland.

I had my autosomal DNA tested at the same time. My test, like my brother-in-law’s didn’t really match up with what I knew about my family’s history. I tried another company and the results were even less enlightening. I was going to give up, but my daughter talked me into doing the health testing offered by 23 and Me. They will only do the health portion if you pay for the heritage test as well. Reluctantly, I sank even more money into my personal DNA project. This time I was rewarded with an analysis that made sense and matched what I knew about my parents’ family history. The test said I was 35% Irish/British Isles ancestry, 32% German/French and 8% Scandinavian. The rest was a mixture of unknown, Eastern European and Finnish DNA. I especially liked that the analysis showed how long ago each ethnic marker appeared. You may wonder why these results were so much different than those of the other two companies. I think it’s because they all use different genetic markers to determine ethnicity, as well as different algorithms to analyze the results. It’s an imperfect “science” at best.

The health part of the test was interesting, but not particularly meaningful. I found out I am of average risk for getting Alzheimer’s disease and low risk for Parkinson’s, and fortunately, not a carrier for any of the 42 common genetic diseases covered in the test. Of course, if I had tested differently, the information potentially could have been life-changing. Beyond the health testing, a lot of the things I learned were rather silly and obvious. I already knew I was a restless sleeper, have light to medium color hair, no dimples and fair skin.

I thought I was finished with DNA analysis. Then I stumbled onto a company, Geneticoncept, which will take your 23 and Me results and analyze them on a deeper level (for a fee, of course). They promised to give me information on my brain chemicals, how my liver metabolizes drugs and hormones, vitamin absorption and my likely response to 141 commonly prescribed medications.

The results provided a tremendous amount of data, so much that it’s overwhelming. And I do have concerns that not all of it is necessarily accurate, as most of the results/recommendations are based on very small sample sizes (750 or fewer people tested). And sometimes one gene that predisposes me to a certain condition appears to be canceled out by another. But it did suggest that for many drugs I am a fast metabolizer, so I should probably start off with low doses for most medications. It also suggested I have trouble absorbing certain vitamins and even advised what supplemental dose to take. As for the results on prescription drugs, I think they could be useful, at least if you have a doctor like mine who is open to suggestions (some doctors aren’t).

In summation, I don’t think the Y-chromosome or mitochondrial tests are that meaningful, although it might be interesting if you wanted to pinpoint your father’s line for some reason. In terms of the autosomal tests, if I had time to do a lot of genealogical research, I would probably recommend Ancestry, as they currently have the most tools to use your data for genealogy and the best database and process for connecting with people who share your heritage. On the other hand, 23 and Me definitely gave me the most clearly defined ethnicity results. I was disappointed in Family Tree DNA, as they were unable to narrow down my ethnicity beyond Western Europe. But I used them because they have high ratings from other consumers, so they might provide better results for someone who has different genetic markers.

As for as the health DNA testing, this area is so new that I’m a bit wary. In fact, I just read an article about a study that had concluded 2 out 5 people using the tests received false positive results. But enhancements are continually being added. For example, 23 and Me recently announced they will soon begin testing for the BRCA1 and BRCA2 genes, which are associated with increased risk for breast and ovarian cancer in women, and breast and prostate cancer in men.

As they collect more data, do more research and refine their analytical techniques, I believe in a few years these companies will be able to offer consumers information that is truly meaningful. Someday doctors may decide what specific drug and what dosage to give you based on your DNA. They may be able to tailor a weight loss and/or fitness program exactly to you, based on your genetic markers. I don’t regret the testing I’ve done, because I find the historical implications of DNA ethnicity testing fascinating. In terms of my personal health, the more information I have, the better. But overall, as is true for pretty much anything offered for a profit, the best advice is caveat emptor:  Let the buyer beware.

~Mary G.