ANHB1102 Lecture Notes - Lecture 9: Lactose Intolerance, Sickle-Cell Disease, Lactase
4 Dec 2018
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Race has no biological basis - social construct. Skin colour occurs in a cline - variation geographically and within areas. Eumelanin (brown black) and pheomelanin (reddish yellow) Believed races existed due to sampling problem - observed distinct populations rather than the cline. Very little of the genome is associated with skin colour. Australia and africa high uv light so same protective mechanism - same adaptation so same external body form not classi cation based on genes. Blood group distribution is also clinal - no relation to skin colour. Not due to an adaptation like skin colour with environment but due to founder effect. Most genetic variation is within human populations (85%) Patterns in external features are not representative of the entire genome. Race emphasises variation between groups when most of the variation is within a group. Eg. pathogens, predators, prey (food) - act as selective pressures. Malaria (pathogen) - plasmodium parasite carried by anopheles mosquito (vector)
