1. Chapter 5 Outline 5.1 Dominance Is Interaction between Genes at the Same Locus, 100 5.2 Penetrance and Expressivity Describe How Genes Are Expressed as Phenotype, 102 5.3 Lethal Alleles May Alter Phenotypic Ratios, 103 5.4 Multiple Alleles at a Locus Create a Greater Variety of Genotypes and Phenotypes than Do Two Alleles, 103

2. Chapter 5 Outline 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype, 105 5.6 Sex Influences the Inheritance and Expression of Genes in a Variety of Ways, 114 5.7Anticipation Is the Stronger or Earlier Expression of Traits in Succeeding Generations, 122 5.8 The Expression of a Genotype May Be Influenced by Environmental Effects, 122

3. 5.1 Dominance Is Interaction between Genes at the Same Locus Genes at the same locus – two versions of the same gene; each version of the same gene is defined as allele.

5. 5.1 Dominance Is Interaction between Genes at the Same Locus Incomplete dominance Codominance

7. Penetrance: percentage of individuals having a particular genotype that express the expected phenotype Expressivity: the degree to which a character is expressed 5.2 Penetrance and Expressivity Describe How Genes Are Expressed as Phenotype

8. 5.3 Lethal Alleles May Alter Phenotypic Ratios A lethal allele: causes death at an early stage of development, and so some genotypes may not appear among the progeny

11. More than 2 alleles at a locus Relationship between allele pairs determines outcome Could be exhibited as dominant/recessive relationship as in duck feathers Could be exhibited in codominance as in ABO blood type

13. 5.4 Multiple Alleles at a Locus Create a Greater Variety of Genotypes and Phenotypes than Do Two Alleles ABO blood group

15. 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype Gene interaction: Effects of genes at one locus depend on the presence of genes at other loci. Gene interaction that produces novel phenotypes

17. 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype Gene interaction with epistasis Epistasis: One gene masks the effect of another gene. Recessive epistasis

19. 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype Dominant epistasis

21. 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype Duplicate recessive epistasis

24. 5.5 Gene Interaction Occurs When Genes at Multiple Loci Determine a Single Phenotype Complementation: determines whether mutations are at the same locus or at different loci The complex genetics of coat color in dogs: Agouti (A) locus Black (B) locus Extension (E) locus Spotting (S) locus

27. 5.6 Sex Influences the Inheritance and Expression of Genes in a Variety of Ways Sex-influenced and sex-limited characteristics

28. Sex-influenced characteristics

32. Sex-influenced and sex-limited characteristics Sex-limited characteristics

36. Sex-influenced and sex-limited characteristics Cytoplasmic inheritance

39. Sex-influenced and sex-limited characteristics Genetic maternal effect

44. Sex-influenced and sex-limited characteristics Genomic imprinting: differential expression of genetic material depending on whether it is inherited from the male or female parent Epigenetics: phenomena due to alterations to DNA that do not include changes in the base sequence; often affects the way in which the DNA sequences are expressed

45. 5.7 Anticipation Is the Stronger or Earlier Expression of Traits in Succeeding Generations Anticipation: A genetic trait becomes more strongly expressed or is expressed at an earlier stage as it is passed from generation to generation.

46. 5.8 The Expression of a Genotype May Be Influenced by Environmental Effects Temperature-sensitive allele: a n allele whose product is functional only at a certain temperature