Chapter 6.1 Interactions Between the Alleles of a Single Gene: Variation on Dominance.

  1. What are multiple alleles or an allelic series?
    What is dominance?
    • Multiple alleles or allelic series are the mutant alleles of a gene and its wild-type allele.
    • Dominance is a manifestation of how the alleles of a single gene interact in a heterozygote.
  2. What is the simplest  type of dominance?
    When will a fully dominant allele be expressed?
    • The simplest type of dominance is full, or complete dominance.
    • Only when one copy is present in a heterozygote.
  3. When DNA molecules replicate, what do they form?
    What is haploinsufficiency?
    What is a null mutation?
    What is haplosufficiency?
    • When DNA molecules replicate, they form identical chromatids.
    • Haploinsufficiency is when one wild type dose is not enough to achieve normal levels of function.

    • Null mutation is a mutation that produces a nonfunctional protein that causes a dominant genotype in where there is an inadequate concentration of a regulatory protein for proper functioning producing a dominant mutant.
    • Haplosufficiency is when a single copy is adequate for full expression (wild type) and the null mutation is fully recessive.
  4. What are three dominant mutations?'
    What is dominant negative?
    How does the spoiler polypeptide work?
    The three dominant mutations are null mutation, dominant negative, and codominance.

    • Dominant Negative is when the polypeptide acts as spoilers or rogues that ruins the wild type polypeptid..
    • The spoiler polypeeptide binds to the wild-type polypeptide and distorts it or otherwise interferes with the function.
  5. What is an incomplete dominance?
    What is an example?
    Incomplete dominance is the term used to describe the general case in which the phenotype of a heterozygote is intermediate between those of the two homozygotes, on some quantitative scale of measurement.

    The four-o'clock flower red and white pedals mating.
  6. What is codominance?
    What is an example?
    How does the ABO system work?
    If there are three alleles in the ABO system, how many genotypes are produced and how many are heterozygotes and how many are homozygotes?
    Codominance is the expression of both alleles of a heterozygote.

    An example of codominance is the ABO example seen in the human ABO blood groups, where there is a codominance of antigen alleles.

    There are three alleles that lead to four blood types of the ABO system.

    There are six genotypes with three homo- and three heterozygotes.
  7. What is a pleiotropic allele?
    A pleiotropic allele is an allele that affects several properties of an organism.
  8. What are the temperature-sensitive (ts) mutations?

    What are the two types of temperature categories?
    The temperature-sensitive mutations are a general class of mutations that activated at higher temperatures and inactivated by permissive temperatures.

    Permissive and restrictive temperatures.
Card Set
Chapter 6.1 Interactions Between the Alleles of a Single Gene: Variation on Dominance.
Chapter 6.1 Interactions Between the Alleles of a Single Gene: Variation on Dominance.