I read an essay by Richard Dawkins recently that gave me pause ("An early flowering of genetics"). Dawkins, the most gifted and persuasive proponent of natural selection since Charles Darwin, reports of Darwin's nascent notions of heredity revealed in his correspondence. The essay by Dawkins appeared as the foreword of Darwin's Descent of Man, and again in an anthology of essays titled A Devil's Chaplain.
Darwin recognized the biggest shortcoming of his theory was that it failed to provide a mechanism for the transmission of heritable traits. But in Dawkins' essay, we learn that Darwin indeed had some insights about that mechanism. He understood that heredity must preserve the variation in traits expressed by progenitors of the next generation. If not, his theory of natural selection would fail. More importantly, competing "blending" theories of heredity contradicted the observation that successive generations of organisms do not become monotonous intermediate forms of the varied ancestral population.
Coincidentally, Darwin at one point argued for a "particulate" theory of heredity citing his experiments with pea plants as evidence. Again, this anticipates Gregor Mendel, the cleric-botanist (only in the Victorian era!) who elucidated the particulate theory of heredity decades later in classic, exhaustive experiments on pea plants in his monastery.
The essay is a wonderful illustration of the depth of Darwin's insight. Dawkins points out that Darwin was nevertheless a product of his time, and revisits some of Darwin's jarring biases and pronouncements on race, as if to expose Darwin's fallibility. Perhaps to set himself apart from darwin's bias, Dawkins curiously advocates for the abolition of the concept of race, arguing that more variation exists within races than between them.
The point was also made in Scientific American a couple of years ago in an article entitled "Does Race Exist?". The argument strikes me as dubious since the physical traits which evolve in certain areas function to confer a selective advantage in some cases (skin color, eyelash length, body habitus), or are culturally selected (lip shape, rump size) and these must co-segregate with other medically important genetic loci. I concede that race is getting tougher to accurately identify in places like Europe, North Africa, and North America, where racial blending has been fairly extensive. I also concede that except for some genetically uniform populations, the concept of race is not useful medically. In more stable populations, such as North Korea, Sri Lanka, or Mongolia for example, the genetic traits that account for race are not mere illusions.
You do not have to claim that race does not exist to passionately defend freedom from prejudice.