BIOL239 Chapter Notes - Chapter 2,3: Sickle-Cell Disease, Consanguinity
6 Mar 2017
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Since can"t do controlled breeding for organisms such as humans and we must look at family tree. Heterozygotes can be resistant to malaria and not display the sickle disease due to co-dominance and the intermediate phenotype the exhibit. Sickle cell: abnormal hemoglobin, sickle-shaped red cells, anemia, blocked circulation, increased resistance to malaria. single nucleotide substitution resultsin incorrect amino acid, resulting in a change in conformation of the -globin protein when deoxygenated. Tay-sachs disease: missing enzyme; build-up of fatty deposit in brain; build-up destroys nervous development; blindness, paralysis, mental retardation. Phenylketonuria (pku): mutation in enzyme in metabolic pathway causes the amino acid phenylalanine to build up. Body deals with this by converting it to phenylpyruvic acid which interferes with early development of the nervous system; mental de ciency in untreated young. Huntington disease (dominant trait): results in a progressive mental and neurological damage; neurologic disorders by ages 40-70. But if errors occur then a certain code is repeated many times.
