BIOL 205 Lecture Notes - Lethal Allele, Citrulline, Signal Transduction
8 Nov 2013
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Gene that controls heart formation brain formation cell divisions. In diploids, recessive lethal alleles can be maintained as heterozygotes. In haploids, temperature sensitive lethal allele are useful. Their phenotype is wild type at the permissive temperature (often room temperature) but mutant at some higher restrictive temperature. Missense: still function but maybe not optimally at higher temps. Isolation of an arginine auxotropic mutation (beadle and tatume 1941) This brillian model, which was initially known as the one-gene-one enzyme hypothesis, then later was changed to one-gene-one-polypeptide. Don"t have arg-3: behaves like arg-3 mutant. General strategey for geneticists using model organisms step 1: treat cell or organisms w/ mutagen (ex: x-rays). Each mutant is checked to confirm single-gene inheritance. Gene interaction is inferred from the phenotype of the double mutant. All three mutant white strains behave as they are recessive as when you cross to wild type we get the typical mendelian 3:1 rations for a monohybrid cross:
