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Chapter14: Human Heredity

Chapter14: Human Heredity. Making a Pedigree. Pedigree A graphic representation of genetic inheritance. Track genotypes by looking at their phenotypes Genotype - allele combination for genes that express a trait (ex. AA, Aa, aa)

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Chapter14: Human Heredity

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  1. Chapter14: Human Heredity

  2. Making a Pedigree • Pedigree • A graphic representation of genetic inheritance. • Track genotypes by looking at their phenotypes • Genotype- allele combination for genes that express a trait (ex. AA, Aa, aa) • Phenotype- physical traits caused by a genotype( ex. AA= red flowers, aa= white flowers Carrier- person who can pass on a disease but it not effected by it

  3. Reading a Pedigree Recessive (aa) Aa Aa • Is this a dominate or recessive disease? • Which individuals MUST be carriers? • I-1,2; II-1 or 2; III-3,4 • What are the possible genotypes for III-1? • AA or Aa aa Aa Aa AA or Aa Aa Aa aa aa

  4. Reading a Pedigree aa AA or Aa Dominate (AA, Aa) • Is this a dominate or recessive disease? • Which individuals MUST be carriers? -None. Cannot have carries for a simple dominate disease • What are the possible genotypes for IV-1? -AA or Aa Aa Aa aa Aa Aa AA or Aa aa

  5. Simple Recessive Heredity • Recessive traits can remain dormant and can appear suddenly; carriers • Tend to skip generations • Some recessive disease are fatal and have late onset; disease starts when you are an adult

  6. Simple Recessive Heredity • Cystic fibrosis disease • 1/28 Americans are carriers • Thick mucus builds in the lungs • Makes physical activity difficult • Must be treated with medication

  7. Simple Recessive Heredity • Phenylketonuria (PKU) • Body lacks enzyme to change phenylalanine to tyrosine • Build up in the body leads to a damaged nervous system • Fetuses are tested to treat with diet

  8. Simple Dominant Heredity • Heredity of many physical characteristics • Widow’s peak hairline • Darwin earlobes • Hitchhiker’s thumb • Traits appear in every generation and is equally spread between males and females

  9. Complex Patterns of Inheritance • Multiple phenotypes from multiple alleles • Traits controlled by more than two alleles have multiple alleles • Blood Type IA, IB, or I, different combinations make blood types

  10. Complex Patterns of Inheritance • Polygenic inheritance • Polygenic inheritance is the inheritance pattern of a trait that is controlled by two or more genes. • Alleles are not dominate or recessive; they represent degrees of expression • All heterozygotes are intermediate in phenotype.

  11. Complex Patterns of Inheritance • Sex determination : • chromosomes, which determine the sex of an individual, are called sex chromosomes. • All other chromosomes are called autosomal chromosomes .

  12. Complex Patterns of Inheritance • Sex-linked inheritance

  13. W+W+ WW WW+ Results not possible using Mendel… WW+ WW+ WW? WW+

  14. Genes linked to X and Y Chromosomes

  15. Complex Patterns of Inheritance • Sex-linked traits: • Traits controlled by genes located on sex chromosomes are called sex-linked traits. • Red-green color blindness • Hemophilia

  16. Complex Patterns of Inheritance X Chromosome Inactivation • Females only need one X chromosome to survive • Inside each cell of a female, one of the two X chromosomes are randomly deactivated (barr body) • Females Calico Cats random colors

  17. Complex Patterns of Inheritance • Environmental Factors: • Temperature, nutrition, light, etc… can effect the phenotype of an individual by changing the expression of the genes • Ex. Arctic Fox • Internal Factors: • Hormones regulate gene expression so a genotype may not express the same phenotype it different individuals • Ex. Peacocks

  18. Human Genetic Disease Presentations • Disease to Pick: • Angelman • Syndrome • 2) Cri du chat • 3) Down Syndrome • 4) Neurofibromitosis • 5) Prader-Wili • Syndrome • 6) Tay-Sachs Disease • 7) Turner Syndrome • 8) Albinism • 9) Canavan Disease • 10) Haemochromatosis • Next Week: PPTs in groups of 4 • Select a genetic disease from the list today • NO LONGER THAN 10 MINUTES!!! • Tell explain the following: • What causes the disease? • What are the symptoms? • How common is the disease? • How can the disease be treated?

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