Chapter 12 Patterns of Heredity and Human Genetics

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Chapter 12 Patterns of Heredity and Human Genetics. Section 1 Mendelian Inheritance of Human Traits. Pedigree. A pedigree is a graphic representation of genetic inheritance. Symbols are used to show the trait being studied and family relationships. . - PowerPoint PPT Presentation


<ul><li><p>Chapter 12Patterns of Heredity and Human GeneticsSection 1Mendelian Inheritance of Human Traits</p></li><li><p>PedigreeA pedigree is a graphic representation of genetic inheritance.Symbols are used to show the trait being studied and family relationships </p></li><li><p>Answer the following about the above pedigree</p><p>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) __________</p></li><li><p>Dominant Autosomal HeredityFollow Rule of DominanceTongue curling Free earlobes Huntingtons disease </p></li><li><p>Huntingtons DiseaseLethal genetic disorder caused by rare autosomal dominant alleleNervous system disintegrates causing loss of control of limbs and mental deterioration.</p></li><li><p>Huntingtons diseaseSince onset occurs between ages 30 and 50, this defect can be transmitted to new generations before the parent knows that he is a carrier.</p></li><li><p>HuntingtonsGenetic testing can determine if a person is a carrier.Carriers will get disease because allele is dominant.</p></li><li><p> </p></li><li><p>Recessive Autosomal HeredityGenetic 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).</p></li><li><p>Cystic FibrosisMost common lethal genetic disorder in white Americans.Characterized by thick mucus in lungs and digestive tract.Food is not digested properlyBreathing is difficult - frequent lung infections</p></li><li><p>Tay- SachsAbsence of enzyme that breaks down a lipid that is produced and stored in the central nervous system. Lipid builds up in brain membranesCommon in Eastern European Jews and Pennsylvania Dutch.</p></li><li><p>Symptoms of Tay-Sachs DiseaseBlindnessProgressive loss of movementMental deteriorationDeath by age 5.See pg 312 for pedigree</p></li><li><p>Phenylketonuria (PKU)Most common in people of Norwegian and Swedish descent.Caused by absence of enzyme that converts phenylalanine to tyrosine (amino acids).</p></li><li><p>Symptoms of PKUNew born appears normal.Once baby starts drinking milk, which is high in phenylalanine, damage occurs</p></li><li><p>SymptomsBuild up in phenylalanine causes severe central nervous system damage resulting in mental retardation. </p></li><li><p>Treatment of PKUAll newborns are tested for PKU.Changes in diet can prevent damage.</p></li><li><p>New Problems With PKUIf a homozygous recessive female becomes pregnant, high levels of phenylalanine in her blood can damage baby.</p></li></ul>