I'm a Physics type myself and sit further from the facts.  We are on (at
least my call)
the brink of a greater enlightenment and discovery.

The fruit fly  has 4 letters - each with upper and lower case descriptors.

Mollusks have many more active ones.(?)  Without doubt due to the
complexity and such.

The Sapiens e.g. us - are even more complex than simple two descriptors
long since given.

Much of the enlightenment has been cloaked by misguided religious
beliefs, time,
and the dissemination of discovery.

Of late, the public announcement of the complex human track runner from
South Africa.
Neither XX nor XY . One researcher indicated a descriptor concept like:
XXXXXX:XXXXXY:...XYYYYY
where various counts of X's and Y's could be within.

The Sapiens are still being shaped up and shook out of the idealized box
we were put into.

But with regards to the Crepidula - I have seen tropical(Sword fish) fish
(we had a store when I was a lad)
that changed sex when the population in a tank was dominated in one
sex.  It wasn't
the offspring, but the adult.  I suspect chemical or hormonal
concentrations shut
down glands and the process begins.  A survival mode long since
programmed that insures
the species to live on.

That is my take.  Hope it doesn't raise an eyebrow.  We are all learning.

I'd think chromosomes could be sorted out but at what cost.  Since the
Crepidula is used
as an example (others as well) it might be analyzed on a short track.  I
see sometime
in the future that Bio classes in the Universities will have Chromo
machines.  Various
ones are specified as the focal point for a point - perhaps family level.


Martin

Doug Stemke wrote:
> Hello All.
>
>     Being a microbiology professional and only a shell-collecting hobbiest I
> sometime back myself into a corner when I teach my Biodiversity course using
> mollusk examples.  We were talking about genetics and a student asked me
> about species that change sex during their life.  I thought immediately of
> Crepidula and passed along the little tidbits I know about the sex change
> involved in that species being driven by bio-chemical control from the
> bottom female. That isn't a whole lot to give them and it ignited more
> questions that I was left scratching my head on.
>
> So, I had no clue as to the chromosomal characteristics of this or for that
> matter any mollusk species.
>
> What are the chromosomal numbers like in most species?  Any info on Crepidula?
>
> Normally what is the situation with sex-chromosomes in mollusks?
> female:male= XX:XY or XX:XO? Something else?
>
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--
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Charter Founder
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