Re: Primes in DNA (was: Definition Challenge)

Windy wrote:
topmind wrote:
Zachriel wrote:
"topmind" <topmind@xxxxxxxxxxxxxxxx> wrote in message

And so on. This is what we are looking for in the genome. Heavens! What are
we to do? Let me think. Something about the study of large collections of
data? It's on the tip of my tongue. Well, anyway, while we ponder that,
let's just group the quaternary digits and count them, shall we?

Yes, certain codons will occure more often than others. Please tell me
this does not take us back to the "they would have noticed" argument
again. You have not shown any evidence that they actually looked for
such on a large scale.

By the way, I don't think an obvious pattern like
AAAATTTTAAAATTTTAAAATTTT would last long because critters tend to keep
"junk DNA" because according to some studies it offers potentially
useful snippets to turn on and off (use) as needed, sort of like a
programming library: you keep the library around even if you don't use
all of it in a given project (eon). Simple repeating sequences like the
above would not serve that purpose very well and are thus likely to be
removed over time due to natural selection. Something that is more
random thus may last longer because it is more likely to coincidentally
contain something useful than repeats do.

You are wrong:
-random sequences are altered by mutation just the same as patterned
ones. So if the message is hidden in the "random" parts, it will get
altered anyway.

No, this is not really about mutations.

-how the hell is a programming library full of random code useful,
anyhow?

The alleged "junk DNA" is not necessarily junk. For example, maybe one
generation of bacteria had a pump to remove excess sulfur. The current
generation does not need a sulfur pump because sulfur is not a problem
in this generation. The gene is switched off and not used. However, the
DNA for it is still there, at least in parts, although nothing
references it or uses it in the current generation.

My understanding of the theory is that "junk DNA" is kind of like a
packrat mentality. A critter keeps "distant experiments" around so
that it does not have to invent everything from scratch. Over the
course of evolution needs come and go. Rather than start from scratch
everytime need X pops up every few million years or so, the bacteria
"learns" to keep stuff around. Using mutations to get new features is
generally slow, plodding, and risky. Borrowing partially-made designs
is generally quicker. Thus, some species keep old junk in their garage.

(Pressure to stay lean and mean means that some species will lose DNA
stuff not of immediate use. It depends on the niche.)

-most genomes are chock full of simple repeating sequences.

I meant "simple" repeats, like TTTTAAAATTTTAAAA.


-- w.

-T-

.

Relevant Pages

  • Re: Junk DNA: A hypothesis
    ... > explanation for junk DNA? ... Most likely selective forces acting on junk DNA are weak. ... great number of mutations, which do not affect the fitness ... Neutral networks are areas where many mutations are nearly ...
    (sci.bio.evolution)
  • Re: Junk DNA: A hypothesis
    ... >> explanation for junk DNA? ... > great number of mutations, which do not affect the fitness ... > Neutral networks are areas where many mutations are nearly ... Let's see if I understand the neutral network theory ...
    (sci.bio.evolution)
  • Re: Get your New Junk here!
    ... On the one hand organisms "wish" to reduce the number of detrimental mutations, which means that there is pressure to improve DNA proof-reading and repair, to the point where the cost of the mutations equals the cost of the proofreading and repair mechanisms. ... On the other hand organisms "wish" to increase the number of beneficial mutations, and in particular "wish" there to be sufficient beneficial mutations to track environmental changes, or keep up in intraspecific or interspecific arms races. ... If say, transposon activity, has a different ratio for these categories from say, point mutations, then increasing the amount of transposon activity (and hence junk DNA) might be beneficial. ...
    (talk.origins)
  • Re: Junk DNA: A hypothesis
    ... the evidence suggests that junk DNA is really junk? ... Selective forces being weak and them not being responsible for adaptations ... >> Neutral networks are areas where many mutations are nearly ...
    (sci.bio.evolution)
Loading