GENE20001 Lecture Notes - Lecture 4: Wild Type, Mendelian Inheritance, Zygosity

• School: University of Melbourne
• Department: Genetics
• Course: GENE20001
• Professor: All

Document Summary

Twinzy is a classic case of gene interaction. Twinzy is a result of a fusion event. In mendel"s mutations , we"ve got something to do with pigmentation, tall and short plants, wrinkled or not. Agouti phenotype causes yellow pigmentation, which is a dominant phenotype (dominant to the brown). It causes a range of other phenotypes such as obesity, wanting to eat too much, not being able to regulate your insulin level and increased tumorigenesis. When one particular variant causes multiple phenotypes, we call it pleiotropic. The mutant allele leads to the over expression of a particular protein. Mutation causes ubiquitous over expression which means that it is expressed in all the cells of the body. When you are heterozygous the dosage of this overexpression is high but not extreme, whereas in homozygotes it"s lethal and we call it recessive lethal. So you cannot be homozygous for 2 copies of the agouti gene.