Example of an autosomal incompletely dominant trait

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Unformatted text preview: somal (Incompletely) Dominant Trait • Familial hypercholesterolemia: blood cholesterol is greatly elevated due to a defect in cholesterol transport. • Mechanism: • Low-density lipoprotein (LDL) is a principle lipoprotein in the transport of cholesterol. • Mutation in the gene encoding the LDL receptor • The LDL receptor transports LDL into cells to be broken down and cholesterol released for use by the cell. Example of an Autosomal (Incompletely) Dominant Trait • Inheritance: • Heterozygotes usually have heart attacks by age 35 (half is NOT enough) • Homozygotes are rare, and often suffer heart attacks by age 2. • Thus, the phenotype is dose-dependent. X-linked (or Sex-linked) Recessive Traits • More males are affected (affected females are rare). • Usual transmission is from a carrier woman to her son. • Daughters of carrier mothers have a 50% chance of being carriers. X-linked (or Sex-linked) Recessive Traits • Not passed from father to son. • Affected woman mu...
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