The Human Evolution Blog

For my podcast this week, I interviewed Dr. Michael Campbell of Howard University about a new technique he and his colleagues have created to detect recent natural selection in coding regions of DNA, i.e., genes. This work is published in the Journal of Molecular Biology and Evolution and you can read it here.

Anthropologists, geneticists, and evolutionary biologists have long been consumed by the question, “What makes humans so different from other apes?” This is a very intriguing and difficult question because all of us know intuitively that humans appear and behave very differently from our closest relatives, the African apes. However, if you look at our DNA sequences, we are actually not very divergent from our fellow apes.  In fact, we share about 99% of our DNA sequence with chimpanzees verbatim. So how can so few genetic differences lead to such different outcomes?

I should also say that anyone who reads this blog or my recent book knows that I am a big proponent of the idea that humans are not really all that different from other animals. Our advanced reasoning serves to cloud the underlying behavioral programs that are strikingly similar to those that operate in other animals.

Despite all that, there are some pretty big differences that are undeniable. Our brain is about three times bigger than chimps; we walk with two legs; we’re much taller and much weaker; we’re less hairy (most of us anyway); and we also wear clothes, cook food, build power plants, and make death metal music. So yeah, we have accumulated some genetic differences and those differences are key to what makes us human.

If we take a look at the 1% difference we have with chimpanzees, those few and far between mutations, we see that they are not spread evenly throughout the genome, but rather occur in “hot spots.” These hotspots are likely the sites of recent natural selection and thus, scientists are keenly interested in discovering and characterizing them. This is what inspired the project that Dr. Campbell and his colleagues embarked upon.

Listen to the episode to learn about this new genomic method and the interesting results that were found. And don’t forget that we create teaching guides to accompany each episode of This World of Humans to help high school and college science instructors incorporate the podcast and its featured articles into their classes.

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