MUTATIONS

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MUTATIONS HUMAN GENETICS

• Chapter 11.3, Chapter 12

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Mutations (11.3)

• Mutation change in DNA sequence
• Mutations can be caused by errors in replication,
  transcription, translation, cell division, or
  external agents.
• Mutations in reproductive cells can affect
  potential offspring (ex inheritable genetic
  disorders)
• Mutations in body cells do not get passed onto
  offspring (ex if an individual develops skin
  cancer)

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MUTATIONS

• THE DOG RAN ALL DAY becomes
• THE DOG ANA LLD AY
• or
• THE DOG RAN ALL DAY becomes
• THE DOG SRA NAL LDA Y
• What happened in each sentence?

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Types of MutationsCan alter the genetic code
causing changes to amino acids and then protein
produced.

• Frameshift - moves reading frame to the left or
  right.
• Deletion a base is deleted
• Insertion a base is added

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Mutations

• THE DOG RAN ALL DAY becomes
• THE DOG RUN ALL DAY
• or
• THE DOG RAN ALL DAY becomes
• THE DOG RAN
• or

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Point Mutation/Substitution One base is
substituted in place of another possibly altering
amino acids (a.a.) produced

• Missense Mutation changes a.a.
• Silent Mutation doesnt change a.a.
• Nonsense Mutation changes a.a. to a stop codon

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• http//highered.mcgraw-hill.com/sites/0072556781/s
  tudent_view0/chapter11/animation_quiz_4.html

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• Non Coding Chromosomal Mutations missing or extra
  pieces of chromosomes, switched pieces, extra
  chromosomes (nondisjunction)
• occurs frequently in plants, super sized
  strawberries
• Few chromosomal mutations get passed onto
  offspring because
• The zygote dies or the mature offspring cannot
  reproduce and is sterile

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• Mutation of genetic material will affect the
  proteins produced

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Sickle Cell result from the change in one base
on Chromosome 11.
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Cause Repair

• Some mutations are spontaneous others can be the
  result of long term
• Mutagen any agent that causes DNA change (ex
  harmful chemicals, radiation)
• Cells have repair mechanisms and special enzymes
  that can fix incorrect DNA.

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HUMAN TRAITS

• Chapter 12, Section 1

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Pedigree

• Pedigree map of inheritance of genetic traits
  from generation to generation

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Karyotype

• Chromosomes come in pairs, inherited from parents
• Karyotype a chart of chromosome pairs, can be
  used to visualize chromosomal abnormalities
• Humans have 23 pairs of chromosomes, 46 total
  chromosomes

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• Autosomes any chromosome that isnt a sex
  chromosome
• Sex Chromosome genes that determine an
  individuals gender (X and Y)
• Sex chromosomes are the last pair on the
  karyotype

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Recessive Heredity

• Caused by recessive alleles
• Attached earlobes, Cystic fibrosis (defective
  protein leads to excessive mucus production in
  lungs), Albinism
• Individual will only display the recessive
  phenotype if its genotype is homozygous recessive

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Dominant Heredity

• Caused by dominant allele
• Freckles, Widows peak, Hitchhickers thumb,
  Huntingtons disease (brain degeneration, doesnt
  appear until later in age), immunity to poison
  ivy
• Individual will display the dominant phenotype if
  its genotype is heterozygous or homozygous
  dominant

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When Heredity Follows Different Rules

• Chapter 12, Section 2

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Incomplete Dominance

• Complete Dominance one allele completely
  dominates over another
• Incomplete Dominance phenotype of a
  heterozygote is in between the dominant
  recessive phenotypes, appearance of a third
  phenotype

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Codominance

• Both alleles for a gene are expressed in a
  heterozygous individual
• Neither allele is dominant or recessive
• Ex Blood type
• BLOOD TYPE.ppt

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Sex Determination Sex-linked Inheritance

• Combination of sex chromosomes (X and Y)
  determine an individuals gender
• Males XY, X chromosome comes from mom Y
  chromosome comes from dad
• Females XX, both mom dad give an X chromosome
• Sex-linked Traits traits controlled by genes on
  sex chromosomes

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• Red-Green colorblindness
• Hemophilia (blood doesnt clot properly)
• Male Pattern Baldness
• Duchenne Muscular Distrophy (muscular
  degeneration leading to eventual paralysis)

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• Most of sex-linked traits are found on genes on
  the X chromosome (X-linked trait) because it is
  larger than the Y chromosome
• X-linked traits display more in males because
  they only have 1 X chromosome, whereas females
  get 2 X chromosomes so they can be carriers of
  the trait but not display the phenotype

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Polygenic Inheritance

• Characteristics that are influenced by several
  genes