BIO207H5 Lecture Notes - Lecture 7: Epistasis, Wild Type, Zygosity
Document Summary
Prof will post what we"re expected to know for the test (up to today"s material) Inherited variation of 1 gene produces mutant phenotype. Not complete depiction of genetic reality because many genes interact together. Mutation of one gene may prevent production of end product. Allele of 1 gene modifies or prevents expression at another gene. Example figure - vermillion pigment (from 1st gene) and brown pigment (from 2nd gene) delivered by white gene product (3rd gene) in fruit flies. No mutation - both pigments delivered -> red eyes. 1st gene mutated - no vermillion pigment produced, brown pigment delivered -> brown eyes. 2nd gene mutated - no brown pigment produced, vermillion pigment delivered -> vermillion eyes. 3rd gene mutated - both pigments produced, but not delivered -> white eyes. All genes mutated - no pigments produced & no delivery -> white eyes. Occurs when genes must act in tandem to produce a phenotype.
