HMB265H1 Chapter Notes - Chapter 3: Missense Mutation, Null Allele, Genetic Disorder

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

Document Summary

Hmb265 lecture 3 readings - molecular basis of genetic polymorphisms & their. Genes encode proteins that cells produce that dictate cellular structure/function. Can find out what genes determine pea colour, or inherited human disease cystic fib. Mutant allele causes sticky mucus secretion in lungs. Dominant allele = round, recessive allele = wrinkled. Rr homozygotes have lots of branched starch molecules = maintain round shape rr homozygotes less converted starch = wrinkled. Rr heterozygotes = enough starch to prevent wrinkling. Normal dominant cf+ allele encodes protein that forms channel in cell membranes of various organs including lungs. Normal allele produces protein that regulates flow of water through cell membranes. In cystic fibrosis, recessive cf disease alleles get nonfunctional versions of protein. Can"t regulate flow of water, so mucus builds up in cells. Scientists extracted healthy dominant allele from healthy mouse and put it in cystic fibrosis mouse and sick mouse was able to produce functional tissue.