HEREDITY AND THE ENVIRONMENT

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Chapter 3

• HEREDITY AND THE ENVIRONMENT

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Some questions well answer.

• How are genes transmitted from generation to
  generation?
• How do genes guide development?
• Do genes predispose us to certain disorders?
• What is genetic testing, counseling, and
  engineering, and what are ethical issues
  surrounding this fast-growing field?
• How does the environment influence the expression
  of genes?
• How might genes influence the environmental
  impact on a child?

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THE PROCESS OF GENETIC TRANSMISSION

• Genotype, phenotype
• Earliest genetic material ovum, sperm, zygote,
  chromosomes
• Process of cell division
• Mitosis cell division to duplicate any cell in
  the body-each pair duplicates
• Meiosis cell division to create reproductive
  cells only-each pair is halved

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THE PROCESS OF GENETIC TRANSMISSION

• DNA molecule (deoxyribonucleic acid)
• Function
• Structure
• Coding for genetic material
• Protein synthesis
• Central Dogma (DNA? mRNA ? protein)
• Functions of proteins

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THE PROCESS OF GENETIC TRANSMISSION

• Alleles
• Homozygous
• Heterozygous
• Intermediate
• Codominance
• Recessive/Dominant
• Alleles in the sex chromosomes

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GENETIC DISORDERS

• Recessive alleles
• Autosomal recessive disorders (PKU, sickle cell
  anemia)
• X-linked recessive disorders (hemophilia, color
  blindness, MD)
• Chromosomal abnormalities
• Autosomal abnormalities (Down syndrome)
• Sex chromosome abnormalities (Turner syndrome,
  Klinefelters, fragile X)

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Genetic diagnostics and engineering

• Prenatal Diagnostic Techniques (4)
• Gene Therapy
• In vitro fertilization

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Ethical Questions for In Vitro

• Frozen embryos-how long, how many
• Use of embryos that are not implanted
• Mixing of eggs and sperm between parents of child
  and donors
• Psychological impact on parents, on children
• Safety of process
• Selection of embryos (genetic disorders/health of
  embryo, better looking embryos, gender

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HEREDITY-ENVIRONMENT INTERACTIONS

• How the Environment Influences the Expression of
  Genes
• How Genetic Makeup Helps to Shape the Environment

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Gene-Environment Interactions

• Range of reaction
• - canalization
• Types of interactions
• - passive
• - active
• - evocative