BIOLOGY 1M03 Lecture Notes - Lecture 21: Overdominance, Phenylketonuria, Epistasis
18 Oct 2015
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Document Summary
Gene: part of the genome that codes for some part of the protein. Allele: a part of that gene (the allelic variants of a gene cause diseases) Mutation/selection balance: purifying selection vs. deleterious alleles, mutation selection balance is what maintains the mutation for achondroplasia (the dwarfism gene) Drift: occurs in small or isolated populations. Tay-sachs disease: when you have a defective protein that messes up your lipid metabolism. Lipids build the sheets of neurons so it messes up your neuron construction and neurological system: a recessive trait (you can be a carrier and not have any effects) If you"re homozygous for this allele you die immediately: present in small pockets of populations that have gone through bottlenecks in the past, evidence suggested drift caused it. If you have one copy of the sickle cell allele, your blood cells are normal and it gives you resistance to a certain type of malaria (falciparum malaria).
