The great mystery of genetics

I’ve been thinking a bit lately about what I consider to be the greatest mystery in the realm of neuroscience and genetics. Since I have no doubt you will be fascinated by this, I will describe it here.

In a lecture I caught on video, neuroscientist Robert Sapolsky described an interesting behavior exhibited by a certain kind of monkey or ape — I can’t remember the specific creature. This particular beast lives in a harem style social network — there’s one male and he gets all the chicks. This alpha male usually has a two or three-year run before a younger, stronger male beats him up and takes control the harem. What does this younger, stronger male do upon ascending to the throne? He finds all the infants currently being nursed by the females in his harem and kills them. As brutal as this may be, it makes a certain sense. This new alpha male has a limited window of time to pass his genes on via sex. Nursing mothers can’t get pregnant, so he needs to do whatever it takes to get them fertile again.

Of course, the question is: how does this monkey know this? Monkeys don’t have language, and even if they did I’m not sure they could understand such complex topics as the timing of fertility. (To be honest, even I was unaware that nursing mothers couldn’t become pregnant while nursing until I watched the video, and I’m a pretty smart monkey.) Since this information can’t be passed on through learning or culture, it must be passed on genetically.

At first, that seems preposterous — how can bands of DNA and RNA pass on something like, “kill your predecessor’s children in order to make sure your new harem will become fertile”? But animals have all sorts of behavioral instincts that seem to be programmed into them by evolution. Dogs circle around three times before taking a nap, for example.

What’s happening in this monkey’s head when he decides to kill these infants? Presumably he’s driven into an excitable, murderous rage — his heart races, adrenaline shoots through his body, muscles tense. And somehow he knows the targets of this rage — baby monkeys. But how can information encoded into DNA “know” that the creature it’s coding for will ever encounter baby monkeys? In a sense, DNA is dumb enough to not even know what kind of creature it is coding for. (Humans share 50% of their DNA with a banana.) How does DNA code for complex behaviors? (Complex always being a relative term.) That is the great mystery of genetics.

My best guess at an answer is somewhat cloudy. I would presume DNA is not saying, “if you ever get to be king alpha monkey, make sure you kill everybody’s kids.” DNA is operating on a much more basic level. Let’s turn to computers for an analogy. You might be running an e-mail program. But that program can be deconstructed to the raw program code written in a particular language like Visual Basic. And that code can be broken down further to what’s called machine language which appears to the human eye as an indecipherable series of meaningless characters. And even that can be broken down to electrical signals traveling the circuitry of your computer. You could say the same for the reality we sense about us. If I am an alpha monkey and I see a baby monkey, what’s really happening is that I’m sensing the light waves reflecting off that baby monkey. Those light waves are hitting my retinal cells, firing off neurons in being interpreted as a psychological construction — a baby monkey — in my brain. And that psychological construction is somehow the connection of lots and lots (thousands? Millions?) of neurons. So perhaps the DNA is programming at this simplified, deconstructionist level. It’s not saying, “when you see a baby monkey, kill it!” It’s saying, “when you encounter a certain pattern of sensory information deconstructed to this very basic level then fire off a complex set of behaviors (which ultimately will lead to the monkey killing the baby monkey.)” This is complex stuff to think about, but I’m essentially saying DNA programs on the biological analogue to the most basic level of computing: the firing of electrical signals.

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