No - there is not a single marker distinguishing races, to the best of my expectations.
But that's not where this article is going. There are statistical differences between groups, even though the groups are not well defined at the boundaries, and though there is no single clear way to distinguish them.
Indeed, the groups almost totally overlap. Almost any white man can find some black man he can out jump, and almost any black man can find a white man who can outjump him. The biggest strongest NBA center is a black man, and since George Mikan usually has been. But there are usually both black and white centers succeeding in the NBA at any given time.
These differences are biological and exist, with 99% overlap and no clear boundary. This article doesn't dispute that, though it does its darndest to cloud that fact. Why? What agenda is it persuing? Not one I subscribe to, of that I'm confident.
The question isn't simply how great the differences are statistically between lightly and darkly complected people (ie do they meet some arbitrary threshold). Folk theories of race consist of claims like the following: "He's fast because he's black." That's a causal claim. What's the most charitable way to construe it? Surely the claim isn't that skin pigmentation itself makes one run faster, otherwise sprinters would train in tanning salons. The most charitable interpretation is that there's some genetic marker for skin pigmentation that is also responsible for one being fleet footed. Ie, the skin pigmentation the running ability have a common genetic cause. A genetic vindication of a folk theory of race would find those common causes. But when we look, they're not there.