HMB265H1 Lecture Notes - Lecture 4: Tyrosinase, Genetic Load, Mutual Exclusivity

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

Document Summary

Lecture 4 mendelian traits in humans and human pedigree analysis. Segregation and independent assortment also applies to humans, such as the molecular basis of albinism, an autosomal recessive condition. Individuals with at least one dominant allele can synthesis tyrosinase enzyme, which converts tyrosine into melanin, a dark pigment. Individuals who are homozygous dominant or heterozygous produce sufficient tyrosinase enzyme, resulting in a pigmented phenotype. Individuals with two loss-of-function recessive alleles don"t synthesize any functional enzyme, so melanin can"t be produced, and you end up with an albino phenotype. This is just one example of dominant and recessive phenotypes in humans: thousands of examples are described in the database, autosomes, not sex chromosomes, are chromosomes 1-22, can be inherited in dominant or recessive fashion. Autosomal inheritance: human autosomal traits are located on the non-sex chromosomes (1-22, they may be inherited as autosomal dominant or autosomal recessive.