Re: Appropriate for Gen Phys? was: comprehending electric/magnetic interactions

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 11:39 AM 7/4/2003 -0500, Jack Uretsky, you wrote:

>  /snip/ Enter the  Y-Chromosome.
>         A recent enjoyable, amusing, (and a bit ribald) book that got a
> rave review in Nature, is <Y: The Descent of Men> by Steve Jones.  Jones
> is an evolutionary biologist and a noted authority on Darwin, as you might
> guess from the title.
>         The theme of the book is the evolutionary self-destruction of the
> Y-chromosome stemming from the fact that there is only one in the male
> (note that I am not specifying species).  This leads to the well-known
> prediction that the human male will become extinct in about 10 Myears,
> simply as a result of reproductive errors.  That is, there is no second Y
> that can serve as a model for correction of an error.
>         The female line, by contrast, is much stronger because the X's
> descend in pairs, enabling the correction of errors in the reproductive
> process.
>         In the last couple of weeks, however, the prediction of the end of
> maleness has changed radically, and it appears that we've all swallowed
> the wrong model.  Analysis of the Y-genome has discovered that DNA,
> previously thought to be "junk", turns out to be duplicates of "real" DNA
> needed for reproduction.  In other words, the Y can correct reproductive
> defects using internal models, rather than an external model like the X
> does.
>         So in the year 2003 we can sing: Hallelujah, mankind (emphasis on
> the "man" syllable) is saved!  This is part of what I think to be the
> excitement of science.

This reminds me: long, long ago, when I worked as a regional field support
engineer for DEC - short for Digital Equipment Corp.,  (which was at that
pre-Intel time, the shooting star of high-tech) it fell to me to provide a
one week technical class in the "decTAPE" which was a reversible, block
addressable one inch spool tape drive.  This thing was intended to be
rugged and reliable and so not only were data tracks duplicated, across the
tape (like two half inch tapes stuck together, in a way) but the coding was
arranged so that if a data block was read in the other direction, the ones
which would play back as zeroes in this direction were arranged to decode a
compatible clock and addressing code.    I thought about it again for the
first time in many years, on hearing about the reverse redundant
transcription code on the Y chromosome.

And I thought: strange, it's usual for engineers to steal neat ideas from
nature, not invent them from scratch. The former method is so much more
common. As an example, it is a pleasure to use the utter simplicity of a
code embodiment of another natural process: the 'genetic algorithm' (GA).


No more than sixty lines of BASIC or Fortran or C  can juggle endless
combinations of multiple parameters describing a machine, a puzzle, an
optimization problem etc.,  and create increasingly better uber-manikins by
working out a given criterion of goodness of the combination, through
hundreds of generations, by saving promising sub-sets, randomizing others.

People sometimes talk of Designed species - but these engineers are aware
that the criteria which they provide to the GA are the 'teleological'
elements of the process,  and they find it not difficult to conceive of a
destructive environment, with the criterion of goodness being their
manikins' survival and fruitfulness.

 At any rate,  the concern in using the G.A. is not in duplication errors
between generations - the default transcription error rate is zero, and
so  mutation needs to be forced, in order to provide some unpredictable and
novel variation.

Brian Whatcott     Altus OK