HMB265H1 Lecture Notes - Lecture 4: Melanin, Retina, Genetic Load

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

Document Summary

Albinism is a recessive condition, its caused by mutations in different genes. Albinism is caused by a lack of lenanin, which is present in melanocytes which are found in the skin, hair, and the retina of the eyes. One particular gene codes for an enzyme known as tryosinase. In individuals with 2 wild types, these people have a pigmented phenotype. In people ith a mutated allele, they have a pigmthis means that the allele is haplo-sufficient. ented phentotype. If both alleles are mutated, no melanin is synthesized. These genes can be inherited in a dominant or a recessive fashion. The affected partent is hetero, the unaffected parent is recessive homo. Domanint is curly hair, recessive is straight hair. It"s a (cid:1007):(cid:1005) ratio of (cid:272)url(cid:455) to straight hair progeny. Only homo recessive individuals will exhibit the straight phenotype. Scientists construct pedigrees of many families or a pedigree that contains many generations in 1 family.