langreiter.com plain, simple: 2008-02-16

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2008-02-16

CREATED BY chris • LAST EDITED BY chris 6126 days AGO

Olivia Judson: A Mutant Obsession

The start of a, if the firstling is any clue, fantastic series surveying "the mutational landscape". I haven't ever seen a description of proteins and amino acids that packs more intuition into a single short paragraph:

"The canonical mutation [...] alters the part of a gene that contains the instruction to make a protein. In case you don't have an intuitive feeling for what proteins are, the easiest way to think about them is as small objects, each with a shape and a function — just as a teacup has a shape for holding tea. Proteins are built out of a kind of molecular Lego; the bits of Lego that are required are listed in the gene. So a mutation to the protein-coding part of a gene often has the effect of altering the protein's shape — like substituting a big Lego brick for a small one, or one with a hinge for one that's rigid."

And where things get really interesting (regulatory elements, a rather amazing system of control structures):

"[...] whereas sequences that encode proteins often evolve rather slowly, so you can sometimes recognize the same gene in humans and jellyfish, switches appear to evolve fast [...]. Altering the way a gene is turned on or off has the advantage of leaving the protein itself unaffected."

"[...] while the number of genes that different animals have does not vary nearly as widely as everyone expected, and does not seem to correlate closely with how complex organisms are, the complexity of gene regulation differs greatly from one group to the next. This allows the same basic set of proteins to be used in ever more elaborate ways."

2008-02-16-mutOb

Jean-Claude Wippler: The strength of Tcl (2003)

"Tcl is one of those languages (along with Scheme and [create Forth]) which are well-suited for creating small domain-specific languages. The reason for this is its total absence of syntax and parsing. When a command is invoked, the arguments are handed over to it - if these are enclosed in braces, then virtually no processing takes place. That means one can define a command which takes a string and interprets it in some very domain-specific way."

2008-02-16-tclTngl