There’s a little “caveman” in all of us. About 1-4%, to be exact. That’s the proportion of the modern human genome that can be traced back directly to ancestral Neanderthal populations, which coexisted with “moderns” for hundreds of thousands of years, before going extinct about 30,000 years ago. You may or may not believe you’re a monkey’s uncle – but you surely are the distant child of Neanderthals.
Perhaps it’s a co-worker, or an old high school bully – maybe even your ex. I’ll bet you’re thinking of someone now who seems to have a little more Neanderthal than average – and probably also wondering how you measure up yourself. I’ll show you exactly how to find that out, and much more.
We have one of these confusing-looking blobs in every cell in our bodies (shown in computer-generated false-color to help differentiate individual chromosomes). Every cell nucleus contains 23 pairs of chromosomes: 22 “autosomes,” and one pair of sex chromosomes (XX in females; XY in males).
Each chromosome is a single strand of genetic material (DNA) about 2 inches long, very tightly coiled into a double helix. Stretched out, each strand would be around 6 feet long! Together, these encode over 3 million base pairs in 32,000 genes – the sum of everything we are, all we have been – and all that we might yet become.
Advances in Human Genomics
The technology for analyzing the human genome has improved enormously over the past 20 years or so. The Human Genome Project had the ambitious goal of sequencing the entire genome (i.e., decoding the double helix into an ordered list of the four basic amino acid constituents, represented by the letters C-G-T-A-…). When it began in 1990, few were optimistic that the project would be completed quickly, so daunting were the computational demands in those pre-Internet days. Yet by 2003 the work was done.
Since then, in parallel with computing power in general, the speed of genetic analysis has increased and the cost has come down to the point where it is no longer a luxury. Through the magic of mass-produced “microarray” chips, genotyping is now available to the masses.
Enter 23andMe, which was founded in 2006 to “empower individuals and develop new ways of accelerating research."
23andMe offers a personal genotyping service. You send them a sample of your saliva, and within a few weeks get back a complete analysis of your genome. From this information, they can determine your ancestry in truly astonishing detail.
Genetic mutations occur regularly, and some of them – those that are beneficial or at least not harmful – persist through all future generations. These are “markers” that can be used to identify from which pre-historic population your ancestors arose.
It is also possible to distinguish maternal from paternal descent, as mitochondrial DNA is only inherited from mothers. So for instance, if you have the K “haplogroup,” you belong to a population that split off from the original U8 group 35,000 years ago, then migrated in waves from the Near East into Europe.
Find long-lost relatives
Of course, the analysis can also reveal much closer relations. (Move over, Maury Povich!) I was adopted, and have been looking for my birth parents for many years. If anyone in my immediate or close biological family gets tested, they will show up as a “match." Finally, I have the means to find them!
In fact, the database does contain my biological 2nd cousin, and several 3rd-4th cousins. These people are also notified of the match, and by mutual consent can share information and contact each other. I have corresponded at length with a 3rd cousin; she is now working to get more of her relatives tested.
23andMe currently has over 650,000 genotypes in its database, with more being added every day.
The Heavy Hand of the FDA
As Matthew McConaughey can attest (well, as the character he portrays in “Dallas Buyer’s Club” could have), the FDA has been busy inhibiting innovation for some time. One of the major benefits of 23andMe used to be screening for genetic markers of health risks – for instance, the BRCA cancer genes that prompted Angelina Jolie’s mastectomy.
On November 22, 1963, President Kennedy was assassinated in Dallas. Exactly 50 years later the FDA, in one shot from a grassy knoll (they’re calling it a “directive”), took out 23andMe’s health-related results: including health risks, drug response, and inherited conditions. If you got tested before that date, you can see all those results. For instance, I am at higher risk for prostate cancer and macular degeneration, but at lower risk for MS and diabetes. If you buy the service today, you only get the raw data and ancestry results – including your Neanderthal percentage.
This makes me spitting mad! If you feel the same, at least now you have somewhere to send all that spit. (They do require a fairly large amount, so if you have an easy-going temperament you might have to work at it a bit to get enough.)
If you’re adopted like me – or want to make sure your child is really yours – it’s still a great deal. There are many heartwarming stories of family reunions made possible through this technology. We can only hope the FDA will eventually come to its senses and give people the benefit of the latest scientific knowledge about genetic influences on disease.
Note that 23andMe does genotyping – amplifying and searching for specific short sequences -- not comprehensive sequencing, which is more involved and still fairly expensive. They can (well, they previously could) tell you which variant of a gene you had – i.e., which SNP was present. An “SNP” is a single nucleotide polymorphism, essentially a point mutation.
What they cannot do is detect things like trisomy-21 (Down’s syndrome), or Huntington’s Chorea, since these arise from repeated sequential copies of otherwise “normal” genes, and can only be detected through sequencing.