Worm Breeder's Gazette 1(2): 20

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Further Characterization of Intersex Mutants

G. Nelson

In Volume 1 #1 of the newsletter an autosomal temperature-sensitive 
sterile mutation (TS17) was reported to have sexually dimorphic 
phenotype: spermatogenesis defect in hemaphrodites and intersexuality 
in 'males'.
Further mapping of this mutation by Ken Lew and Johji Miwa has 
located TS17 in linkage group IV.  The second allele of this gene is 
also linked to IV.  Therefore, the intersex gene is distinct from 
either of the two known transformer genes.
Observation of Feulgen stained mutant worms shows that TS17 
hermaphrodites grown at 25 C are totally devoid of spermatocytes and 
mature sperm.  At the time of normal spermatogenesis gonadial cells in 
the position of normal spermatocytes begin to mature in the pattern 
characteristic of oocytes.  These oocytes can be fertilized by 
outcross sperm, but in the absence of mating they pass through the 
empty spermatheca and undergo endoduplication of their DNA becoming 
highly polyploid.  These polyploid oocytes are laid as 'squashy eggs'.
TS17 intersexes are variable in morphology.  They always have a 
normal-looking bursa and nearly always contain mature oocytes.  
However, the vulva is not always present and when present is often 
abnormal so that matings of intersexes to males have not yet been 
successful.  Consequently we do not know whether the intersex oocytes 
are functional.  The intersex gonads vary from normal hermaphrodite 
shape to male configuration.  Occasionally they contain sperm.  Often 
the gonad is broken up into lumps packed solid with nuclei, or it 
loops around in odd patterns and may contain highly polyploid cells 
distinct from polyploid oocytes.
For analyzing morphology I recommend the use of a camera lucida with 
stained preparations.  Feulgen is already in wide use amongst worm 
breeders and Hematoxylin/eosin or toluidine blue complements Feulgen 
by providing information about cytoplasm and nucleoli.