Homozygous mutant _InR_ gene lethal for D. melanogaster?

[George P. Masologites]

Hello,

I am reading over a report by Tatar et al in the 6 Apr 2001 issue of
Science (v. 292 pp 107-110) on the effects of mutant InR (insulin-like
receptor) genes.  It is noted that "genotypes homozygous for mutant
InR have been reported to be lethal."  At what point is it lethal?  It
is always/usually so?  Does it matter which allele of InR?

Thanks,

George
guilds at mail.serve.com