Problem:
Question 1: In the nematode C. elegans, sup-5 is a Trp tRNA gene. Mutant alleles of sup-5 function as an amber (tRNA) suppressor.
a. What is the anticipated sequence change to the DNA sequence of the sup-5 gene that would be associated with the suppressor (mutant) allele?
Indicate the sequence of the double stranded DNA, as well as which strand is the template strand for transcription (or, the direction of transcription of the sup-5 gene).
b. Animals homozygous for the suppressor allele of sup-5 are viable. What does this suggest about the genome of C. elegans?
Question 1:
a. For the C. elegans sup-5 suppressor allele (of #14), do you expect this allele to be dominant or recessive to the wild type allele? Explain your reasoning.
b. The unc-22(s32) allele of the C. elegans unc-22 gene has a premature stop codon that is amber suppressible. Animals homozygous for unc-22(s32) have muscle defects, and exhibit a "twitching" phenotype. unc-22(s32) is recessive to unc-22(+). Let sup-5(s) = the suppressor allele, and assume that unc-22 and sup-5 are unlinked (on separate chromosomes). Animals of unc-22(s32)/unc- 22(+); sup-5(s)/sup-5(+) genotype are crossed with each other. Among the offspring, what proportion of normal-moving, and what proportion of "twitching" animals do you predict?
Show your calculations, but you do not need to write out any explanation.