Re: What's smallest known "self-sufficient" genome


"John Edser" <edser@xxxxxxxxxx> wrote in message news:e3t3av$1ht0$1@xxxxxxxxxxxxxxxxxxxxxx


"Perplexed in Peoria" jimmenegay@xxxxxxxxxxxxx wrote:-

JE:-
What has any of the above got to do with the question? This was: when
one
cell divides by mitosis on an almost equal basis into two cells how does
what you wrote enable anybody to decide between:

1) Just the one original fitness independent parent is now deceased
reproducing itself 100% efficiently into two fitness independent
individuals.

2) The original fitness independent parent remains alive reproducing
just
the one fitness independent individual.

JM:-
Rather than challenging people to provide an experiment that
distinguishes,
John, why don't you suggest the experiment, if you think there is one.

snip<

I have: TDF. Self consistent to what I have argued for over 5 years in sbe,
the less efficient but more complex case of unequal budding will be selected
over the less complex but more efficient equal mitosis if and only if, the
TDF using the unequal budding system increases compared to the TDF of the
equal mitotic system which remains maximized at just 2 (within the same
population).

I'm sorry, John. I still don't get it. I asked how you distinguish
equal mitosis from unequal budding when at first glance it looks pretty
equal. Your answer deals with which of the two cases will be favored
by selection. It doesn't answer the question I thought we were talking
about which is, for example, how could we determine that E. coli is a
budder, but Salmonella is a symmetric divider?

Hunt and IRR have suggested one way of answering the question. Keep track
of which of the two 'daughters' inherits the 'old' pole of the parent and
which inherits the 'new' pole. Then observe whether one or the other of
the two daughters exhibits a senescence in its long-term reproductive
potential.

Of course, at the genomic level, we know from the classic Meselson-Stahl
experiment that neither model is correct. We don't get two new genomes
and we also don't get one old genome and one new genome. Instead, we
get two genomes that are half old and half new. But, as you point out,
genomes aren't everything, so the experiment that Hunt and IRR are talking
about also tells us something about the truth.

My main point is that we don't and can't ever know the whole truth. Instead
we have models of the truth that work reasonably well within limits.


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