Poor Willi Hennig?

Jonah Thomas JEThomas at ix.netcom.com
Mon Sep 25 14:05:27 EST 1995

In <schwarze.ccomail-2109951724280001 at> 
schwarze.ccomail at starbase1.caltech.edu (Erich Schwarz) writes: 

>Couldn't resist this one....I have only one question, seeing as how I do not
>like to flame people in public. I dont understand how Ludvig, the original
>poster, can think that molecular systematics is bullshit seeing as how it is
>the only method I know of that utilizes only homologous characters! (If you
>take the care to align the sequences properly) How can you build a phylogeny or
>a taxonomy using anything else and call it realistic?

I don't think it's bs, but here's a possible way to imagine Ludvig
thinking so:

The molecular techniques seem to me to be ideal for estimating
ancestry.  You get a solid feel for what's related to what, and a
better feel than is otherwise available for how closely things are
related.  OK, but suppose that isn't your problem?  What if you're
actually interested in selection and responses to selection?  Then the
molecular data is mostly misleading.  It gives you megs of data with
maybe tens of kilos of changes and perhaps dozens to hundreds of them
that were somehow strongly selected, and no indication which is which.

At least we're getting beyond the frontier days, when people found
"the" E coli beta-lactase sequence, or "the" rabbit myoglobin sequence.

Or maybe Ludvig has some other question he thinks is very important.
If it's a question that molecular techniques tend to steer people away
from, he might reasonably feel that molecular techniques are bad.  We
swerve the questions we _can_ swerve just as we look for the kiss where
the light is goo.

I'd like to see more effort in other directions, provided we had some
solid indication that the effort might pay off.  Lacking that, we might
do better to collect a lot more sequence data and look for interesting
questions (and answers to questions we hadn't thought to ask) from the
results.  But I can understand the frustration.

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