BIOL 121 Study Guide - Midterm Guide: Photic Sneeze Reflex, Y Chromosome, Zygosity

• School: UBC
• Department: Biology
• Course: BIOL 121
• Professor: Brett Couch

Document Summary

Affected traits shown in the pedigrees is extremely rare, determine the most likely mode of inheritance for each pedigree. (these pedigrees are from griffiths et al. , introduction to genetic analysis. Answer key: a) assign genotypes to as many individuals as you can. Make sure to define the symbols that you use to represent various alleles. Let"s define a1 as the allele causing achoo and a2 as the allele not causing achoo. The affected woman must have at least one a1 allele, since she has achoo. Her husband must have at least one a2 allele, since he does not have achoo. The two unaffected daughters must also have at least one a2 allele, while the affected son must have at least one a1 allele. All modes of inheritance, except for y-linked, are possible in this case: Make sure that no other interpretation of the pedigree is possible (i. e. , all other possibilities can be ruled out).