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Unformatted text preview: by X rays, and two tryptophan-requiring mutants (A and B) were isolated. These tryptophan-requiring strains were plated in large numbers to obtain rever-tants to wild type. You failed to recover any rever-tants from mutant A and recovered one revertant from mutant B. This revertant was crossed with a normal wild-type strain. a. What proportion of the progeny from this cross would be wild type if the reversion precisely re-versed the original change that produced the trp 2 mutant allele? b. What proportion of the progeny from this cross would be wild type if the revertant phenotype was produced by a mutation in a second gene located on a different chromosome (the new mutation sup-presses trp 2 )? c. Propose an explanation of why no revertants from mutant A were recovered. (Dana Burns-Pizer.) 44200_16–p521-544 3/17/04 9:12 AM Page 544...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08