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Genetic Disorders. In general…. Most traits are neither harmful or helpful Ex. Blood type – there is no advantage or disadvantage to having A or B blood type Some are helpful Ex. Coloration on an animal Mimicry Camouflage Some are harmful Ex. Health risks. Autosomal diseases.
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In general… • Most traits are neither harmful or helpful • Ex. Blood type – there is no advantage or disadvantage to having A or B blood type • Some are helpful • Ex. Coloration on an animal • Mimicry • Camouflage • Some are harmful • Ex. Health risks
Autosomal diseases • Autosomal traits – carried on autosomes • 22 pairs of autosomes • 1 pair of sex chromosomes • X and Y
Inherited Diseases • Some diseases are genetic (passed down from one generation to the next) • Many inherited diseases result from mutations • What is a mutation? • Most are autosomal • Cystic fibrosis • Huntington disease • Sickle cell • Others on sex chromosomes
Cystic fibrosis (CF) http://www.youtube.com/watch?v=L10W9MdRjPs • Disease affecting sweat and mucous glands • Chloride ions outside of cells lead to problems maintaining salt balance • Affects lungs – thicker and stickier mucous • Difficulty breathing • Supports bacterial growth • Also affects pancreas, liver, and sex organs • Autosomal recessive
Huntington Disease • Degenerative disease of the nervous system • Progressive – worse over time • Eventually breaks down nerves in the brain • Causes: • Uncontrollable movements • Mental deterioration • Premature death • Autosomal DOMINANT • Generally has late onset http://www.youtube.com/watch?v=MRZoM5L5dak
Sickle Cell • Changes in hemoglobin (a protein in blood) • Red blood cells fold into a sickle shape • Problems: • blockages in blood flow • Weakness and pain • Damanges brain, heart and spleen • Can be fatal • Autosomal recessive • Incomplete dominance • 1 allele means you have the sickle cell trait • Increases chances of surviving malaria
Hemophilia http://www.youtube.com/watch?v=uhyD0vdQDZs • Unable to produce normal clotting protein • Bruise easily • Can die from minor cuts – can’t stop bleeding • Commonly sex linked trait • Occurs mostly in what gender?
Genes and the Environment • Behavior or certain substances can affect the expression of a gene • Heart disease and diabetes • Genetic component accelerated by diet and exercise • Skin cancer • UV rays strongly related to skin cancer but a higher risk in fair skin and light hair and eyes
Pedigrees • Chart or family tree, that traces the inheritance of a trait • Carriers have one copy of each gene
Horizontal lines indicate marriage or parentage • Vertical lines are children • Generations are numbered • People are numbered • Males = squares • Females = circles • Solid = affected • Blank = unaffected