Biology 1001A Lecture Notes - Lecture 12: Cyclic Adenosine Monophosphate, Melanocortin 1 Receptor, Melanocortin

• School: Western University
• Department: Biology
• Course: Biology 1001A
• Professor: Tom Haffie

Document Summary

Crossing two pure bred parents will always result in 100% heterozygous ofspring: (pp x pp) = 4 x pp. Crossing two f1 generaions (ofspring of pure parents) results in a phenotypic raio of 3:1: (pp x pp) = pp pp pp pp helps us idenify the dominant allele. Pigment producion is the result of melanin producion: 2 types of melanin produced by melanocytes: 2)red (pheomelanin: stored in melanosomes exported out to skin cells (kerainocytes, mc1r (melanocorin 1 receptor protein) embedded in melanocyte membrane controls melanin producion. W allele high cyclic amp (camp) levels --> black melanin. Low cyclic amp (camp) level --> red melanin. Agoui signalling proteins (asp) deacivates mc1r and lowers camp levels. Mc1r is always on insensiive to hormones --> camp levels are always high --> eumelanin. Heterozygote"s have both the b and w allele: b allele always produces eumelanin --> camp levels always high, w allele produces eumelanin because of high camp levels.