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

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    16-Dec-2015

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  • Slide 1
  • Chapter 12 Patterns of Heredity and Human Genetics Section 1 Mendelian Inheritance of Human Traits
  • Slide 2
  • Pedigree A pedigree is a graphic representation of genetic inheritance. Symbols are used to show the trait being studied and family relationships
  • Slide 3
  • Slide 4
  • 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) __________
  • Slide 5
  • Dominant Autosomal Heredity Follow Rule of Dominance Tongue curling Free earlobes Huntingtons disease
  • Slide 6
  • Huntingtons Disease Lethal genetic disorder caused by rare autosomal dominant allele Nervous system disintegrates causing loss of control of limbs and mental deterioration.
  • Slide 7
  • 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.
  • Slide 8
  • Huntingtons Genetic testing can determine if a person is a carrier. Carriers will get disease because allele is dominant.
  • Slide 9
  • www.about-dementia.com/huntingtons/hd-causes.php
  • Slide 10
  • 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).
  • Slide 11
  • 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
  • Slide 12
  • 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.
  • Slide 13
  • Symptoms of Tay-Sachs Disease Blindness Progressive loss of movement Mental deterioration Death by age 5. See pg 312 for pedigree
  • Slide 14
  • Phenylketonuria (PKU) Most common in people of Norwegian and Swedish descent. Caused by absence of enzyme that converts phenylalanine to tyrosine (amino acids).
  • Slide 15
  • Symptoms of PKU New born appears normal. Once baby starts drinking milk, which is high in phenylalanine, damage occurs
  • Slide 16
  • Symptoms Build up in phenylalanine causes severe central nervous system damage resulting in mental retardation.
  • Slide 17
  • Treatment of PKU All newborns are tested for PKU. Changes in diet can prevent damage.
  • Slide 18
  • New Problems With PKU If a homozygous recessive female becomes pregnant, high levels of phenylalanine in her blood can damage baby.

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