Tag Archives: Just so Stories

The butterfly effect in embryology

How the snake lost its legs. No, this isn’t a Just So story a la Rudyard Kipling, but a fascinating paper in Cell (vol. 167 pp. 598 – 600, 633 – 642 ’16 ). All it takes is a 17 nucleotide deletion in ZRS (Zone of polarizing activity Regulatory Sequence), an enhancer of gene expression involved in limb development. The enhancer is at least 1,300 nucleotides long (but I can’t find out just how long ZRS is). The deletion removes a binding site for a transcription factor (ETS) which turns on some limb development genes.

ZRS has long been known to be involved in limb development, and mutations distributed over 700 nucleotides are associated with a variety of human limb malformations. So the authors sequenced the enhancer in a variety of species (including many snakes) and found that only snakes had the deletion.

Then they put the snake ZRS into genetically engineered transgenic mice and found markedly shortened limbs. That was all it took. Reintroducing the missing 17 nucleotides into the transgenics restores normal limb development. Staggering what genetic technology is capable of.

Where does the butterfly effect come in? Because the enhancer is 1,000,000 nucleotides away from some of the genes it controls. If you were studying sequences around the genes it controls, you’d never find the deletion (until you’d run through a large number of grad students). Human biology (with limb malformations) told the authors where to look.

Straightened out 1,000,000 nucleotides is 3,200,000 Angstroms,or 320 microns (32 times the size of the average 10 micron nucleus). Remarkable how it finds its target. You might be interested in a series of posts which try to imagine these goings on at human scale — blowing up the nucleus so it fits in a football stadium with our double stranded DNA blown up to the size of linguini with a total total length of 2840 miles. Start here –https://luysii.wordpress.com/2010/03/22/the-cell-nucleus-and-its-dna-on-a-human-scale-i/

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Book Review — The Kingdom of Speech — Part II

Although Darwin held off writing up his ideas for 20 years, fearing the reaction he knew would come from the church, the criticisms that really bothered him the most were those of fellow intellectuals about the evolution of language. They began immediately after the Origin of Species came out in 1859, by linguists and later by Wallace himself. Even worse, one critic mocked him. The idea that language evolved from animal sounds was called the bow wow theory, or language arose from sounds that things made (the ding dong theory).

This is all detailed in pp. 54 – 87 of The Kingdom of Speech, about which I knew very little. If any real experts on the early history of evolutionary theory are out there and reading this and disagree, please post a comment. I am assuming that the facts as given by Wolfe are correct (I’ve already disagreed with him about his interpretation of some of them — https://luysii.wordpress.com/2016/10/03/book-review-the-kingdom-of-language-part-i/).

The real attack on Darwin’s ideas is that man’s mental capacities were so far above those of animals, that there was no missing link (particularly since there were lots or primates still around). By this critique man was so special, that a special act of creation (not evolution) was called for.  It’s theology getting in the back door, but of course this is essentially the claim of all theologies — special creation by a superior being(s).

In his later book “The Origin of Species and the Descent of Man” – 1871 (which I’ve not read), according to Wolfe Darwin made up all stories (many involving his beloved dog) to show the antecedents of all sorts of things in animal behavior — Darwin actually said that language originated with the songs birds sang during mating. Female protolanguage persists today in mothers cooing to their babies. Darwin spent a lot of time discussing his dog — how it recognized other dogs as a sign of intelligence. Religion came from the love of a dog for his master (Wolfe claims that Darwin said this in the book– I haven’t read the Descent of Man).

Darwin’s second book didn’t get much response. Postive reviews avoided his reasoning, and negative reviews said it was thin. In 1872 the Philological Society of London gave up on trying to find out the origin of language, and wouldn’t accept patpers about it. The Linguistic Society of Paris did this even earlier (1866).

Evolutionists basically stopped talking about language from 1872 to 1949.

As soon as Mendel’s work on genetics was discovered, evolution went into scientific eclipse. Here was something that wasn’t just armchair speculation about things happening in the remote past, something on which experiments could be done.
Mendel’s experiments with green peas took 9 years and involved 28,000 plants.

In a fascinating aside, Wolfe notes that Mendel actually sent his work to Darwin. Tragically it was found unread with its pages uncut in Darwin’s papers after his death. In all fairness to Darwin, he and his peers had no idea how heredity worked and there are parts in The Origin of Species in which Darwin appears to accept the inheritance of acquired characteristics (the blacksmith’s large muscles passed on to his son etc. etc.). I don’t think you can read the Origin without being impressed by the tremendous power of Darwin’s mind, and how much work he put in and how far he got with how little he had to go on.

Wolfe says Darwin’s ideas about the origin or language were mocked by Gould  one hundred years later (1972) as “Just So Stories”, fantastic bizarre explanations for why animals are the way they are — see http://etc.usf.edu/lit2go/79/just-so-stories/. I’m not so sure, the citation for this gives an article  Sociobiology which Gould and Lewontin (see later) relentlessly attacked. Gould himself saw what he wanted to see in his book “The Mismeasure of Man” — for details see — https://luysii.wordpress.com/2011/06/26/hoisting-steven-j-gould-by-his-own-petard/

As you can see,The Kingdom of Speech is full of all sorts of interesting stuff, and I’m not even halfway through talking about it.

Next up, linguistics, to include Noam  Chomsky and his admission that he doesn’t understand language or where it came from.