peter hunt, CSIRO, a previous letter for any/any worms

fodoran at LUDENS.ELTE.HU fodoran at LUDENS.ELTE.HU
Sat Mar 25 13:00:51 EST 1995


From:	LUDENS::FODORAN      23-MAR-1995 20:24:10.66
To:	MX%"jamison at news.cso.uiuc.edu"
CC:	FODORAN
Subj:	Re: strange patterns of inheritance

You can deinitely say more if you put single any/any NON MUTANT phanotype
hermaphrodites (virgin L4-s, of course) to plates and see what they do (or do
not) segregate). What is the phenotype of the male (any/0) progeny of the
any/any X any/0 crosses? Are they all (ANY) phenotypes?

If your any mutants is a conditional mutant, I would not be surprised with this
I used to cross dpy-8 (e1321ts) males to dpy-8 (e130) hermaphrodites and found
some Non-Dpy guys.

Do your any/0 males carry the same allele as any/any hermaphrodites?
What is the situation if you cross your any/any homozygous with any/0 males
and than cross the resultant males back to the maternal stock? Do you have the
same unusual inheritance?

One more question. If you were who isolated any, did you crossed out your
strain properly? Whenever I used to find a mutant in Sydne's lab his first
comment always was: "Just cross out!"

If everything is all right and no mistake or devil or mite did troubles, I
would suspect the genetic background. 

I can imagine, for instance, that for complete expression of any in the
phenotype another mutation is needed somewhere in the genome. Most probably on
the X chromosome, close to the locus of any. Suppose you did cross out your
mutant strain, you made them homozygous for both any, and for this second,
closely linked mutation, let's call it some. When the animal is homo,- or
hemizygous for both some and any (that is, some any/some any or some any/0
phenotypes the penetrance is 100%. But animals heterozygous for some but
homozygous for any produce less then 100% penetrance. If it were so, my logic
is wrong. So some must be located on one of the autosomes rather than X.

The less probable explanation is that some is an extrachromosomal
gene which is under the control of an autosomal recessive gene. When your
animal of any/any genotype is heterozygous for this autosomal gene (let me call
it body), that is any(X)/any(X); body(+)(A)/body(A);some (mitochondrial) so,e
is inactive and the exression of any is troubled. This question should easily
be answered if you make reciproc crosses between any/+ X any(+)/0; and any/any
X any(+)/0 and any(+)/any X any/0 males and compare the segregation of the
phenotypes in both sexes as well as the expected and found sex ratio.

Any of the hypothetical gene (either some and/or body) may also influence the
sex specific expression of any. If any is a moderately male chauvinist allele,
its expression maybe sutrubed only in one of the sexes (in the hermaphrodite).

It is definitely something what you should not passed by.

Let me return if your mutant is a conditional or became conditional in a
different genetic background.

The only way is tro make back crosses and reciprocal crosses, I think.

Sorry for the long letter.

Andras Fodor
 
result.





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