From genes to organisms

    • How do genes work?
    • Meiosis
    • DNA Code

      Review

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Other kinds of inheritance

  • Incomplete Dominance (flower color)
  •  

    Y

    gamete

    y

    gamete

    Y

    gamete

    YY

    Yy

    y

    gamete

    Yy

    yy
  • Other Kinds of
    Non-Mendelian inheritance

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    Genetics of Blood-types


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    Dominant alleles are not necessarily more common than recesive ones

    Blood
    Type
    U.S.A.
    Ave%
    JapaneseNative
    American
    A40%39%16%
    B10%22%4%
    AB4%10%1%
    O46%29%79%

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    Sex Chromosomes

      In Humans, the sex chromosomes - X & Y - carry different genes, for example, SRY on "Y"
      • If SRY is present, testes develop in the embryo 2nd mo. Swyer syndr.
      • If SRY is absent, ovaries develop
    • Most mammals: ♂ XY, ♀ XX
    • Most birds: ♂ ZZZW "heterogamety"
    • Some reptiles gender is determined by the incubation temperature of their eggs. Tuatara ++
    • Abnormalities

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    MEIOSIS: making gametes

    PROPHASE I homologous chromosomes pair
    METAPHASE I align at equator
    ANAPHASE I homologous chromosomes separate
    TELOPHASE I haploid chromosome number
    PROPHASE II begin 2nd division
    METAPHASE II chromosomes at equator
    ANAPHASE II chromatids separate
    TELOPHASE II four hapolid gametes
    Review Meiosis            Mitosis

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    MEIOSIS


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    From Genes to Organisms


    DNA > RNA > Protein > Enzymes, Hormones

    (Replication) Transcription Translation

    Primary structure of proteins
    is the sequence of Amino Acids


    (Peptide Bonds)


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    CODON: a sequence of 3 nucleotides in mRNA that selects for an Amino Acid.
    " A genetic 'code word' containing three 'letters.' "
    " More than one 'word' for each amino acid. "

    RNA Codon

    Amino Acid


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    RNA > Protein

  • 21 amino acids occur in nature (un-natural)
  • 64 possible combinations of 3 nucleotides
  • Amino Acid

    RNA Codons
    "synonyms"

    GCU
    GCC
    GCA
    GCG
    UAA
    UAG
    CUU
    CUC
    CUA
    CUG
    GUU
    GUC
    GUA
    GUG

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