Bio1151 Chapter 14 Mendel and the Gene Idea
  1. Gregor Mendel studied the              of several characters with peas.

  2. Mendel proposed "heritable          " (now known to be genes) to explain his results based on two principles of inheritance.

    1. Law of              .
      • The           allele determines a heterozygous individual's trait, or            .

      • The phenotype ratio of the offspring can be calculated from a              model called the          square.

      • A testcross can be used to determine the           of an organism with the dominant phenotype.
        Monohybrid Cross activity

    2. Law of Independent             .
      • Crossing true-breeding parents differing in two traits produces            in the F1 generation heterozygous for both traits, and       phenotypes in the F2 generation.
        Dihybrid Cross activity

    Review: Mendelian genetics activity
  3. Extending Mendelian genetics.
    • In             dominance, the phenotype of                is somewhere between the phenotypes of homozygotes.

    • In              , two dominant alleles affect the phenotype.

    • Some traits exhibit            inheritance which often shows               variation.

    • In            , a gene at one locus may alter the phenotypic expression of a gene at a second locus.

  4. Inheritance in human families can be studied by analyzing a           showing the inheritance of alleles across generations.