[Drosophila] Re: initial population and inserts

Mark Thorson via dros%40net.bio.net (by nospam from sonic.net)
Wed Sep 12 11:23:05 EST 2012

Laurence Mueller wrote:
> The rover and sitter polymorphism is a larval behavior that is naturally
> polymorphic in D. melanogaster populations.  Larval crowding increases the
> frequency of the rover phenotype. Marla Sokolowski has done most to the
> research on this behavioral trait and her publications should be read to
> understand this trait. Larval and adult crowding also has many non-trivial
> effects on the evolution of a host of life-history traits in Drosophila too
> numerous to summarize here. However, if you consult my web site below you
> will find ~20 years' worth of research on this topic including some review
> articles.

Thanks for the link.  You certainly have a lot
of experience!  Refs 2 and 29 didn't help me much,
but 50 is great!  I'll have to read it again.
You mention some factors that I've been wondering
about, such as the effect of using adults from
young vs. mature cultures.  In general, all of
my cultures are propagated when young, but I've
been considering whether I should propagate from
the very first adults to emerge to apply selection
pressure favoring short life cycles.

I haven't been expecting much genetic variation
in my cultures, which are based on what I assume
are a highly inbred strain.  Out of about 2000
cultures, I've only had one case of a wild fly
somehow getting into a culture and contaminating
the genetics.

Currently, I propagate from the most vigorous
cultures.  If there is any genetic variation,
I assume these are the winners.  I'm thinking
more about variation due to bacteria the flies
carry with them on their feet and in their gut.
Because I'm not sterilizing my media or using
methyl paraben, I assume my media has its own
ecology of yeast and bacteria, and I believe
a lot of the variation in the productivity of
my cultures is due to the bacterial component.
My working theory is that good cultures have
good bacteria -- bacteria that don't overgrow
the media or don't overgrow until late in the
life of the culture.

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