Bio3400 Chapter 4 Extensions of Mendelian Genetics
  1. Alternative forms of a gene are called          ; the allele that occurs most frequently in nature is called the       type.

  2. A           (change in the DNA) that causes the reduction or loss of a wild-type function is called a loss of           mutation. If the loss is complete, the allele that results in a       allele.
  3. Some loci exhibit             dominance, where neither allele is dominant.

  4. Some genes exhibit              , where both alleles contribute to the phenotype of a               . An example is the     blood group.
  5. Some traits are controlled by           alleles. Examples include the human      blood group and the        locus in Drosophila.

  6. A loss of           mutation may behave as a recessive         allele in the homozygous state, but exhibit a separate           phenotype in a heterozygote.

  7. Genes present on the    chromosome exhibit unique patterns of inheritance due to the presence of only one X chromosome in males.

  8. Some phenotypes are affected by sex           and can be either sex -          if the phenotype is restricted to one sex, or sex -             if restriction is not absolute.
  9. Phenotypic expression may also be influenced by the              as well as by genotype and result in variation in the               and             of the genotype.

    • One component of the              is genetic             , such as the position effect.

    • Another component of the              is temperature, and many phenotypes show temperature sensitivity.

  10. In cases of genomic             , phenotypic expression may depend on the           origin of the chromosome.