01:119:115 Lecture 18: 18. Human Genetics (Chapters 14. and 15)
14 Jan 2016
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Document Summary
Genetics scientific study of inherited variation. Difficulties in studying human genetics: few offspring, long generation span (20-30 years, can"t do experimental mating between individuals unethical & illegal. Instead analyze results of mating that have already occurred: pedigree analysis study of family tree, dna sequencing identify order of nucleotides. Shows inheritance patterns within the family over several. Predict inheritance of phenotypic traits that are controlled by genotype at single locus. Offspring in birth order from left to right. Shaded = having a specific trait being studied. Many genetic disorders are autosomal recessive. Recessive allele codes for malfunctioning protein or no protein at all makes enough protein. Heterozygote = carrier normal phenotype dominant allele. Recessive allele defective or absent chloride transport channels in plasma membranes. Lead to buildup of cl- ions outside the cell. Symptoms = mucus buildup in internal organs: sickle-cell disease. Caused by the substitution of a single amino acid in hemoglobin protein in red blood cells.
