I thought the narrative was that race doesn't exist? That we're all the same race?
Yup. We're all the same specie. "Race" is just an arbitrary label used to make convenient distinction among a group of individual that would other wise mate together : e.g.: breeds of dogs, etc.
How then is is possible that one can determine so called race by examining the genetic profile of a person?
Is it possible we were lied to and that race is indeed something that can be determined as a composition of genes and other genetic data?
Short answer: Nope, it's not possible.
Not so short answer: Well depend on what you define as "races" i.e.: you'll need to constantly redefine your arbitrary "race" label along as the set of gene that you try to use to map it. With that definition of "race" drifting farther and farther away from what biggots with an agenda would like it to be.
Long answer: Remember that the only valid real barrier is *specie*. i.e.: between groups that *cannot* mate together. Inside that division, all individual can mate together. Humans are specially good at that "mating" (well, maybe except some basement dweller): because from our dawn we've been one of the most mobile specie, only bested by birds and some big aquatic animals. Humans do tend to get around a lot. As a result our specie is constantly under heavy genetic mixing.
You can put some arbitrary labels (hey, let's put together individual that have darker skin tone in one big arbitrary bunch and call them niggers!)
You can even find some labels that are actually convenient (statistically, people who typically come from Caucasian ancestry tend to have a bit higher probability for some disease and a bit lower for others).
But if you got into the details, it starts to get muddy, you'll find that some people that you put in one of your arbitrary categories come from completely different lineage that split quite some time before, whereas other that you wanted to put out of that label actually share much more recent ancestry.
(That white supremacist biggot over there ? He want to be put in a special category, aside "non whites" ? well on the surface it might look like some vague idea like correlating it with skin pigmentation. Except that among those non-white he'll probably put native american, but also african and north african. And his grand-dad happens to be from an italian immigrant family, and over the course of history southern european have had a lot of exchange with northern africa. See where I'm heading ?)
So, in short what works well to separate breeds of dogs (which are bred in very controlled manners and you can somewhat keep something like a breed more or less pure) absolutely doesn't work with human that fuck around a lot.
Same for the genetics.
You'll be able to spot a few marker (let's say: a gene that helps control the base amount of melanin in the skin). But once you start using this, you'll notice that a lot of the "wrong people" end in the "wrong category".
That specific list of markers you've assembled together, will consider some of the white supremacists as non white (because of the complex mixed ancestry most people have) while failing to cast aside one of their usual target.
An idealist (like me) would dream that this would help some of the biggots to realise that we aren't that much different under the skin, we're so much mixed that there's a high probability that the biggot has a bit in their blood what their usual target is.
Saddly, the reality will be that they'll be still endlessly tweaking around their genetic definition of "race", to constantly keep itt more or less matching their agenda. They'll never have a definite set of markers, they'll constantly need to patch them. And over time it will evolve to something that at the genetic level doesn't remotely look like what they pretend to be (by the time they manage to include all their friend and exclude all their targets, melanin-related gene probably won't be significant as much as some weird genetic disease that happen to be differently distributed between the groups they consider).
So overall, the the genetic make-up of the population doesn't conveniently split it into separate races. Due to the constant intermixing over time, it's more or less a complex continuum with a few blurry tendencies that you could make here and there. We do tend to fuck around a lot. We're not arbitrarily bred into separate breeds. (Well except maybe in some very isolated cases, like royal families. You could probably manage something to genetically sort royalty in a few categories. Probably based on the distribution of hemophilia :-D )
Cue in all the various genetics and statistic studies that get reported on slashdot about most recent common genetic ancestror, etc.
Something that can be determined as a composition of genes and other genetic data?
There are *other* things that can be determined using a composition of gene.
Using the kind of approach mentioned the slashdot entry, it would be possible to make a control code that only allows a category like "most of the people with anemia".
i.e.: you could use it as a way to filter people based on the few disease that have a very simple and very well known genetic composition. (some of the anemias, some of the hemophilia, some form pulmonary cystic fibrosis, most of dawn syndrome, etc.)
and guess what: these *are* routinely used as medical tests.
with enough work you could also design something that could detect the eyes of elisabeth taylor. as in the real eyes or the real cleopatra actress.
a genetic signature specially crafted around the genetic make up of a specific individual.
and then, even that will probably report a few positive match in complete random people spread across random places on the world (most of whom will propably have the same more or less general shade of blue), while still failing to detect a few people who have very similar eye, but have a different set of genes that happen to have mixed in a different way but ending up with the same shade in result.
eye colour are polygenic (lots of genes contribute to them) and complex. same situation for all the other characteristics that a biggot might want to split races. environmental factors are also in play.
You can't make a perfect "this is a nigger" or "lynch / do not lynch" genetic test. The whole idea doesn't make any sense.