Monday, December 16, 2013

Inheritance of Acquired Characteristics

I'm a layman when it comes to biology and evolution, but I know ideology when I see it, and this latest attempt to reanimate Lysenko's corpse is ideology-driven.  Let's back up. Back in the old days, there were two basic theories of evolution — Darwin's and Lamarck's. Now, where life comes from is one question, but the fact that evolution at least occurs on a small scale is pretty clear.  That is, organisms change over time because of pressure from the environment. Lamarck's notion was that over its lifetime, a giraffe actually stretches his neck longer to reach food, so when he reproduces, his offspring inherit that longer neck.  The next generation stretches it still more, till we get long-necked giraffes.  Darwin's notion was that some giraffes, because of random mutations and genetic combinations, are born with longer necks, and that they have an advantage over their short-necked brethren for reaching food, so they tend to survive more, and to reproduce more.

The mechanism for the latter theory is at least intuitively imaginable, but for the Lamarckian view, what mechanism could "tell" the reproductive organs to make the next kid's neck longer? Nothing obvious springs to mind.

Well, the Lamarkian view formed the basis for how communists thought about such things, so that was their notion about how to create an egalitarian paradise — Force everybody to live according to communist ideology, and the next generation would be born tending to do so, and sooner or later the whole human race would be born communists, and the state would wither away.

And since communism itself has mutated and evolved a bit into political correctness, attempts are being made to revive Lamarkism, so we can start up some intense social engineering with the knowledge that we'll be remaking following generations into natural-born liberals with all the right characteristics.  Greg Cochran demurs.  From his Blog HERE.

Inherited memories

In a recent paper in Nature Neuroscience, Dias and Ressler trained mice to fear the smell of acetophenone.  They claim that this reaction was passed on to their offspring, and to the following generation.
I don’t believe a word of it.  It would require a mechanism that takes the epigenetic states of genes in the brain, sends that information down to the testes, and then somehow imprints it on the germ cell precursors.  And it would have to do this in a very special way, because many epigenetic changes that are the product of learning wouldn’t be the right thing at all during embryogenesis and development: somehow you’d have to pass timing information as well – info that says “methylate this sucker when you’re three weeks old, but not before”.  Genes are like a recipe, but this patch would be more like a program.  And it’d take a tnuctipun – or better – to prepare it.
According to the blurb at Nature, Kerry Ressler is a neurobiologist and psychiatrist at Emory University. In other words, he’s already a good deal more likely than average to be a flake.  He became “interested in epigenetic inheritance after working with poor people living in inner cities, where cycles of drug addiction, neuropsychiatric illness and other problems often seem to recur in parents and their children.  So he’s motivated.  He’d like this to be true.  Too bad.
We’re going to see more and more articles like this: people want to hear it. Tyler Cowen certainly does, but then he may not really be people.  None of this research will ever be replicated by anyone careful and honest, but that has hardly stopped a flood of analogous nonsense in the social sciences – for example, how poverty reduces your IQ, unless your name is Abel or Ramanujan.
If the progress of Science were inevitable and unstoppable,  I wouldn’t worry, but that is not the case in the human sciences.  Look at mental illness, where Freudians supplanted people who were at least trying to figure things out.  Look at archaeology, which progressed from halfway accurate ideas about European prehistory to pots-not-people: if we just click our heels together, we can make past violence disappear.
There are more things yet to be discovered than are dreamt of in our philosophy – but there’s even more bullshit.  And that’s what this is.

1 comment:

  1. Poverty will contribute to low IQ as a consequence of brain damage due to poor diet and medical care. However, consider the following: over time people with higher IQ's due to genes escape poverty, those with lower IQ's for the same reason get stuck. Those who get stuck then engage in substance and alcohol abuse, damaging their germ plasm leading to a dumber next generation. Mostly Darwin but a hint of Lamarck maybe?

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