BSC 315 Lecture Notes - Lecture 10: Mutagen, Wild Type, Epistasis
8 Feb 2017
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Mutant allele: an allele with low frequency in the population, typically one that results in a non-wildtype, rarely observed phenotype: mutation: the alteration itself, e. g. , the substitution of base g for a in dna. Also mutant allele: mutant: an individual that contains the mutation. In contrast to polymorphic genes: alleles ia, ib and i are alternative wildtype alleles of a polymorphic gene, not mutant alleles. Mutations rise spontaneously (very infrequent) or can be induced (infrequently) by treatment with mutagens (chemicals or radiation that damages dna) P: seeds from true-breeding purple plants (genotype pp) treat seeds with mutagen (x- rays) F2: plant multiple offspring from each f1. Look for f2 families in which plants have wihte flowers. No mutation (>99%): pp seeds mutation, pp seeds, f1: pp plants self, f2: all pp (purple) New mutation (>1%): pp seeds mutagen, pp* seeds, f1: pp* plants self, f2: p- (purple_ p*p* (white) Suppose seven new white flower strains are discovered.
