From: hal@finney.org
Date: Sun Feb 03 2002 - 13:38:51 MST
Damien Broderick writes:
> No. *Both* strands contain genes, running in
> opposite directions. Did you know that? Am I the only idiot in the room?
I did not know that, but come to think of it, it does make sense.
Let's consider ourselves a little transcriptor machine, looking to read
some DNA and make RNA from it. Here's some. Now, which strand is which?
And which way is "forward"? The DNA extends for thousands of miles in
each direction on our scale. It's twisted around itself so there is no
way to distinguish one strand from a passive mirror. And one direction
looks like the other. So there is no reason we can't read genes in
either direction, and on either strand.
The only reason I could see for evolution to prefer using a single
strand and a single direction were if that created a more compact and/or
efficient way of packing all the genes into the DNA. The real mystery
to me is why efficiency is seemingly not a factor and why junk DNA is
allowed to proliferate. But given that efficiency is not an issue,
then in hindsight it is predictable that both directions and strands
could be used.
Hal
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