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dominant markers

Garth I. Patterson patterson at frodo.mgh.harvard.edu
Wed Nov 16 11:59:46 EST 1994

As I promised, I have collated the answers I got to the following post
from last week:

>I would like to be able to do crosses with some existing strains used as
>females.  These strains have no markers that will allow me to identify
>hermaphrodite cross progeny.  Are there any dominant markers that I 
>could introduce into my male strain that I can use to let me identify cross
>progeny?  One suggestion that I have already gotten is a lin-12 dominant 
>allele.  However,  the hermaphrodites that result will be unable to mate, 
>which is not the most convenient for me.  If anyone knows of a dominant 
>marker that allows males to mate, e-mail it to me.  I will post a summary 
>of the results.

As you can see, I got a terrific response.  You have your choice of a
large number of dominant markers.  I have done minimal editing of people's
responses to get this summary into an easily read format.  Thanks to
everyone for your help!

--For both you would have
to find cross-progeny under Nomarski, which is a pain in the butt.  from 
hengartn at cshl.org (Michael Hengartner)

deg-1 (u38). 
--I use deg-1(u38), which is X-linked, so the males are hemizygous.  It is 
tricky to score, but it has worked for me. (from 
rhind at mendel.Berkeley.EDU ( Nick Rhind))

dpy-5 (e61)I
dpy-13 (e184)IV
Several dpys also work, but you need a practiced eye:
Strategy:  het males mate, score semi-dpy progeny.From: cori at itsa.ucsf.EDU 
(Cori Bargmann)

--I always had really good luck with dpy-13(e184). It's a semi-dominant, 
so that dpy-13/+ is a semi-dpy male which mates quite well. You'll only 
pick up half your cross progeny, though. (from jamison at csl.ncsa.uiuc.edu 
(Curtis Jamison) and from David.Greenstein at mcmail.vanderbilt.edu)

Some people can score dpy-10/+ and dpy-11/+, but they are almost
subliminal.From: cori at itsa.ucsf.EDU (Cori Bargmann)

dpy-25(e817sd) II
--dpy-25(e817sd) II/+ hets are semi-dpy, nonetheless males are rather 
good maters. (from lmichel at lgme.u-strasbg.fr  Michel Labouesse)

flu-3 (from JJTHADEN at life.uams.edu)
--flu-3, which according to Siddiqui & Babu (Science 210:330-2  1980 ,
gives rise in heterozygotes to mosaic patches of 
intestinal cells with altered autofluorescence under UV light.  I have no 
idea about ease of scoring, but how many people have a UV light source on 
their dissecting scopes? (from JJTHADEN at life.uams.edu)

lin-12 (n137)
--only the heterozygous males mate, het hermaphrodites and homozygous 
do not, so that can be a problem later.  The muv phenotype is fairly easy to 
score. (From Josh Kaplan via Garth Patterson 
patterson at frodo.mgh.harvard.edu)

--mec-4(e1611dm)X males mate.(from David Greenstein 
(David.Greenstein at mcmail.vanderbilt.edu)
also from lmichel at lgme.u-strasbg.fr  Michel Labouesse)

--For rol-6(su1006), I have used unintegrated transgenes, which are nice 
because they are easy to get rid of, and homo- or heterozygous integrated 
transgenes.  The males mate fairly well in my hands.(from 
rhind at mendel.Berkeley.EDU ( Nick Rhind)   

--sqt-3(sc63)is a useful marker. It is temperature sensitive, homozygous 
Dpy, heterozygous Roller. Het males raised at the permissive temp mate 
fine. You'd have to then do your crosses at 25 and look for Roller cross 
progeny. (from meera sundaram, Han lab sundaram at beagle.Colorado.EDU>)

--We have had fairly good luck mating the dominant alleles of
unc-1.  They are coilers as males, and I will have to look back
in my lab book from a couple years ago to see how many males
we put on a plate.  However, I know we were successful and it
gives a phenotype easy to score.  (from pgm2 at po.CWRU.Edu (Philip G. 

--unc-22, the nicotine-induced "twitch" or vibration in a background
of paralyzed wild type is supposed to be dominant.  I like the twitch 
test but I've only tried it with homozygotes so far.

--One marker I once used is unc-70(e524ts)V. The e524 males are very 
active in moving and mating well at 25C, the nonpermissive temperature, 
and e524/+ het is easy to tell by its curly movement at 25C. You can find it 
in the worm book(Wood, CSH)P551.  Since e524 males mate more 
effectively at 15C(it looks wt) than 25C, I would keep  the parents at 15C 
for mating, and transfer the eggs to 25C.
(from Chenhui Wen, Iva Greenwald's lab, columbia university  
<wc47 at columbia.edu>)

unc-108 (n501)I
unc-103 (e1597)III
unc-8 (n491)IV
unc-70 (n493)V
--Use heterozygous males of the following strains (dominant alleles of the 
uncs).   These heterozygous males all mate, and it is easy to score cross-
progeny as
semi-uncs.  (From: cori at itsa.ucsf.EDU (Cori Bargmann); also from "Leon 
Avery" <leon at eatworms.swmed.edu 

unnamed locus
--I have dominant alleles at two loci on X.  The males are still able to mate
fairly well (I use a higher mating ratio than with N2's; about four males
per hermaphrodite).  The phenotype that is dominant is ivermectin
resistance (they are also recessive or semi-dominant for a dyf phenotype).
You can make males and mate them with your strain on NGM plates 
overnight (or longer; up to about 36 hours) and then transfer the
hermaphrodites to drug plates (add 5 ng/mL IVM to warm agar 1% DMSO).  The
hermaphrodites will lay eggs before they die, and only outcross progeny
will survive.  I have done this many times and it always works providing
the cross works (I can check this because I usually use an unc strain as
the hermaphrodite, and I can see whether or not there are non-unc progeny
on the "crossing" plates).  Anyway, I hope I have explained this well
enough. If you are interested in getting these strains or want to know
more please write back.  Also you can see an article I put in WBG (issue
before last).  (from phunt at chiswick.anprod.CSIRO.AU (Peter Hunt)) 

unnamed locus
--I also have a roller integrant on X.  from 
David.Greenstein at mcmail.vanderbilt.edu   

Other strategies:

Another thing you can do is purge the hermaphrodites of sperm.
Transfer them every day untill they are laying unfertilized
oocytes and mate them.   (from David Greenstein 
David.Greenstein at mcmail.vanderbilt.edu; also from cori at itsa.ucsf.EDU (Cori 

use PCR markers with Bergerac males. (from cori at itsa.ucsf.EDU (Cori 

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