HMB265H1 Lecture Notes - Lecture 17: Wild Type, Brca2, Alu Element

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

Document Summary

Transposition: first discovered in the 1940s by mcclintock, she noticed that tere were frequent breakages on chromosomes in maize. Breakage at ds locus caused a loss of wt: examples: spotted kernel is an unstable phenotype, there are two heterozygous alleles at different loci. One of the loci has lost the wt allele due to breakage at the ds locus. Because of the breakage/loss of wt, there is an expression of recessive alleles in some cells. A different phenotype will be expressed (colourless/shrunken/not shiny: the ds has jumped out (needs the presence of ac to do so) of the c locus (pigmented locus), interfering with the wt function. This causes the recessive colourless phenotype from most of the cells. It needs ac in order to move . It is a non-autonomous element: if ac is in the c locus, there will be the wt allele (spotted phenotype).