HMB265H1 Lecture Notes - Lecture 19: In Situ Hybridization, Reading Frame, Haploinsufficiency

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

Document Summary

Sister chromatids are never separated from each other. This leads to copies that can be easily seen under a light microscope: in situ hybridization can then be used to find location of genes in this chromosome. Deletions: intragenic: small deletion within gene, multigenic: many genes deleted (shown below) Del (df) homozygotes offspring usually inviable or lethal. Gene imbalance in del heterozygotes (might result in haploinsufficiency) Consequences here are often more severe, as many genes are deleted. Deletion loop: when pairing of normal homolog with the deleted homolog will result in a loop, this lines up everything perfectly, but the portion that doesn"t have a pair will form a loop. Pseudodominance: deletions can uncover a recessive, mutant phenotype, normally recessive alleles, such as the one shown below, will appear to show dominance. It is not really dominance because it is within dominant region. These sites can be very useful for mapping on chromosomes via complementation.