HMB265H1 Lecture Notes - Lecture 6: Mendelian Inheritance, Null Allele, Dihybrid Cross

• School: UTSG
• Department: Human Biology
• Course: HMB265H1
• Professor: Maria Papaconstantinou

Document Summary

Lecture notes: extensions of mendelian genetics (part 2) Middle is a null mutation - in the coding section. Last is a mutation within the promoter - nothing made. Phenotypes of last two would be the same. When mutant allele at same locus can"t complement each other, they are allelic. Two mutant alleles can"t complement each other - indicator of allelism. Long history of breeding, so a good genetic model. Take red tomatoes, and subject to chemical and ionizing mutagens. Looking for mutants in the progeny - different colour. Cross the mutants together to find where the mutations occur in. All individuals after are green, so it is allelic. At the molecular level, it"s two diff mutations - but still non-functional. Two genes acting on the same trait is complementation. These two genes function as a regular dihybrid cross. Same method of transmission as seen in the pea plants, genetically.