The beautiful unpredictability of heredity

When I get up off the ground from working in the garden, I walk just like my grandfather walked when he was doing the same thing. It’s embarrassing, but I can’t stop until I’ve gone a few paces and can straighten up. I’m not sure why I find it embarrassing except that he was really old, and I am still so young.

Sometimes my wife says, “That’s just like your father.” Somehow the way she says it doesn’t sound as if she is pleased. She says while she doesn’t want to be married to my father, she isn’t necessarily displeased that I act like him. She just finds it humorous. 

Most people think children are just some strange conglomeration of their parents’ attributes. My parents thought I was a strange conglomeration, but they used to argue a lot about which part of the conglomeration I inherited from each of them. But it’s more than that. An equal number of colored beads from each parent isn’t poured into a jar and mixed together. Somewhere, in all the combining of cells, genes get recombined in mysterious ways. 

Actually, the way they are mixed isn’t entirely mysterious. Scientists now know quite a bit about how these things happen. We know where the chromosome might break and know how another different chromosome might connect. The process is mysterious in that the results are, so often, totally unavoidable and completely unexpected.

Even if we know a great deal about the parents, we are absolutely helpless at predicting the details of the offspring. We simply can’t predict in advance the details of the new body, let alone the spirit and soul. Every birth is a lonely miracle, a new color, a new star.

There are numerous cases where a son or grandson has the same twitch that the grandfather has. But there are zero cases in which anyone has successfully predicted who will inherit that twitch. Heredity happens and, when it does, we note it. But no one is crazy enough to try to predict it. 

This is probably a good thing. If my parents knew what they were going to get when they got me, they might not have bothered. It’s human nature to think that the things we want will be good for us no matter how much history shows us that it isn’t always so. In fact, it seems that the very things we want are often the sources of our greatest sorrows. I’ve always said that the secret of being a good parent is in choosing the right kids. Thankfully, I delegated that to my wife and she is an excellent “child chooser.”

As good as it might be that parents cannot predict their children, it’s probably even better that the children get little say in who their parents will be.  My parents were pretty good given their circumstances, but some kids really suffer. Then, of course, my parents weren’t the same as my brother’s parents.  They were 10 years older when they had me and had already put up with him for 10 years. Whew!

While predicting physical inheritance is hugely difficult, predicting the spirit and soul of new children is impossible. I’ve been reading a book called “The Fellowship.” It’s about the early lives of four of the Inklings, the group of friends and academics J.R.R. Tolkien, C.S. Lewis, Owen Barfield and Charles Williams. That such minds and abilities could come from those of such diminished childhoods is truly miraculous. 

I know scientists don’t like to use words like miraculous, although I suspect many great scientists think of themselves as pretty special. They seem to think that what they’ve accomplished they did all by themselves and that their parents played no part. Anyway, it is still a mystery how two things can be twirled together into one, and the result can be so unavoidable and unpredictable in nature and nurture.

Gary McCallister, .(JavaScript must be enabled to view this email address), is a professor emeritus of biological sciences at Colorado Mesa University.


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