Chapter 12 Patterns of Heredity and Human Genetics Section 1 Mendelian Inheritance of Human Traits

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<ul><li> Slide 1 </li> <li> Chapter 12 Patterns of Heredity and Human Genetics Section 1 Mendelian Inheritance of Human Traits </li> <li> Slide 2 </li> <li> Pedigree A pedigree is a graphic representation of genetic inheritance. Symbols are used to show the trait being studied and family relationships </li> <li> Slide 3 </li> <li> Slide 4 </li> <li> Answer the following about the above pedigree a. What is the sex of I 1? ___________________ b. How many children does IV 2 have? ___________ c. How many children of IV 12 have cancer? ____________ d. List all of the males who have polyps (carriers) __________ </li> <li> Slide 5 </li> <li> Dominant Autosomal Heredity Follow Rule of Dominance Tongue curling Free earlobes Huntingtons disease </li> <li> Slide 6 </li> <li> Huntingtons Disease Lethal genetic disorder caused by rare autosomal dominant allele Nervous system disintegrates causing loss of control of limbs and mental deterioration. </li> <li> Slide 7 </li> <li> Huntingtons disease Since onset occurs between ages 30 and 50, this defect can be transmitted to new generations before the parent knows that he is a carrier. </li> <li> Slide 8 </li> <li> Huntingtons Genetic testing can determine if a person is a carrier. Carriers will get disease because allele is dominant. </li> <li> Slide 9 </li> <li> www.about-dementia.com/huntingtons/hd-causes.php </li> <li> Slide 10 </li> <li> Recessive Autosomal Heredity Genetic disorders caused by recessive alleles. Most genetic disorders are caused by this type of allele. Cystic fibrosis, sickle -cell anemia, Tay - Sachs disease, Phenylketonuria (PKU). </li> <li> Slide 11 </li> <li> Cystic Fibrosis Most common lethal genetic disorder in white Americans. Characterized by thick mucus in lungs and digestive tract. Food is not digested properly Breathing is difficult - frequent lung infections </li> <li> Slide 12 </li> <li> Tay- Sachs Absence of enzyme that breaks down a lipid that is produced and stored in the central nervous system. Lipid builds up in brain membranes Common in Eastern European Jews and Pennsylvania Dutch. </li> <li> Slide 13 </li> <li> Symptoms of Tay-Sachs Disease Blindness Progressive loss of movement Mental deterioration Death by age 5. See pg 312 for pedigree </li> <li> Slide 14 </li> <li> Phenylketonuria (PKU) Most common in people of Norwegian and Swedish descent. Caused by absence of enzyme that converts phenylalanine to tyrosine (amino acids). </li> <li> Slide 15 </li> <li> Symptoms of PKU New born appears normal. Once baby starts drinking milk, which is high in phenylalanine, damage occurs </li> <li> Slide 16 </li> <li> Symptoms Build up in phenylalanine causes severe central nervous system damage resulting in mental retardation. </li> <li> Slide 17 </li> <li> Treatment of PKU All newborns are tested for PKU. Changes in diet can prevent damage. </li> <li> Slide 18 </li> <li> New Problems With PKU If a homozygous recessive female becomes pregnant, high levels of phenylalanine in her blood can damage baby. </li> </ul>

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