Further thoughts on people at the beach
September 14, 2012 § Leave a comment
I wrote recently about my experience at the beach — the occasion on which I (re?)-discovered how badly we were made.
This only confirmed something I had known already from ornithology: bird atlases prefer to use artists renditions (drawings/paintings) than photos of the actual birds because the artist rendition can picture the idealized, perfect bird of its species (Plato!) while the actual photo will show an actual bird, which is more likely than not to be somehow different from the mean — i.e. not representing the “correct look”.
Think about what this means: whenever you take a photo of a specimen in nature you are more likely than not to be photographing a mutant — a reproductive “mistake”. These mistakes are a necessary part of nature, of course, without which (“mutation”) there can be no “selection” — i.e. no improvement, everything will be static, we will all look the same, and probably will be exterminated by the next common cold virus; but they are mistakes all the same.
Ergo, my observation at the beach was right on.
Now, here comes an article in The Economist:
“The latest study to this effect has just been published in Nature by Kari Stefansson and his colleagues at deCODE Genetics, a genetic-analysis company based in Reykjavik that was founded to take advantage of Iceland’s excellent medical records and its unique genealogical history. Recent immigrants apart, the relationship of almost everybody on the island to everybody else is known back as far as the first census, in 1703. In many cases it is known back to the first human settlement of the island, in 874.
Dr Stefansson’s study does not reach as far back as that. He and his colleagues examined 78 trios of father, mother and child who are all still alive. In some cases they looked at grandchildren as well. Their goal was to examine the number of new mutations—traits not found in the normal body cells of either parent—in children.
The average answer is about 63.
The average answer is about 63. That number, however, varies widely—and the main factor involved in this variation is the age of the father. Mothers transmitted an average of 14 mutations to their children, regardless of age. Fathers showed a much wider range: 20-year-olds passed on an average of 29 mutations; 30-year-olds (the average age of fatherhood in Dr Stefansson’s sample) passed on 49; and 40-year-olds passed 69.”
Think about it: there are at least 63 mistakes (on average) in the way your genome has attempted to reproduce those of your parents. Sixty-three!
And here is a further complication:
“According to Alexey Kondrashov of the University of Michigan, an expert on the matter who wrote an article in Nature to accompany Dr Stefansson’s study, about 10% of mutations are damaging.”
On average, each of us carries 6.3 damaging mutations — ways in which our genome has changed in reproduction for the worse; ways in which it differs from that of our parents to our detriment. I have 6.3 times as many faults as my father!
The ancient sages were right: each successive generation is worse than the one before!