BIO207H5 Study Guide - Sickle-Cell Disease, Histone H3, Chromatin Remodeling

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20 Jul 2014
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Complete genetic linkage; no crossing over, only parental forms. Incomplete genetic linkage; more common, mixture of parental & recombinant. Recombination frequency (r=no of recombinant gametes/total no of meioses) varies between different pairs of genes depending on distance between the genes. 10. 1 sickle cell disease (scd) autosomal recessive. Scd is caused by structural abnormality of hb affects in carrying capacity of o2. Hb has hundreds of variants, most are rare. Symptoms include severe muscle pain when sickle-shaped blood cells in the circulation are numerous enough to reduce blood flow in small vessels, leading to o2 deprivation in tissues causing pain and long-term damage. Sickled rbcs are easily damaged and are removed from the circulatory system & cannot be replaced quickly enough leading to chronic anemia. Hb are tetramers with two -globin & two -globin. Each carries one heme (iron) which reversibly binds to o2. (141aa) & (146aa) are structurally & functionally similar (3 exons, 2 introns).