Inheritance

• What are dihybrid crosses?


  Punnett Square crosses involving two heritable traits. This works out for 16 possible off-spring options
• What does a Heterozygous, Homozygous dominant genotype look like in a dihybrid cross?

  BbYY
• What is co-dominance?


  When both alleles in a heterozygous individual are expressed, resulting in a phenotype that shows both traits.
• What is incomplete dominance?


  When each potential genotype is unique, so a new intermediate phenotype is shown
• What is multiple alleles?


  When more than two alleles correspond to a genotype. Examples include blood-type.
• What is pleiotropy?


  When a single gene influences multiple traits or phenotypes. For example the allele for sickle-cell anemia influences blindness, heart attacks, and liver faliure.
• What is Polygenic Inheritance?


  When multiple genes contribute additively a small amount to a phenotype. For example, skin color, height, or weight.
• What are lethal alleles?


  A mutated gene that disrupts biological processes, causing partial or complete lethality of an organism.