Chapter Eight

• Monohybrid cross


  A genetic cross performed to observe the inheritance of alleles and phenotypes for a single gene
• Punnett square


  A square diagram used to predict the genotypes of offspring
• Codominance


  Happens when two traits are independently and equally expressed
• Test cross


  When an individual expressing the dominant phenotype but with an unknown genotype is crossed with a homozygous recessive individual
• The results of a test cross indicate whether the individual with the dominant phenotype is homozygous dominant or heterozygous
• Dihybrid cross


  A genetic cross used to observe the inheritance of alleles and phenotypes for two genes
• Unlinked genes


  Genes located on different chromosomes, or far apart on the same chromosome
• Linked genes


  Genes that are found close together on the same chromosome and are likely to be inherited together
• Independent assortment


  The random orientation of homologous chromosomes along the metaphase plate during metaphase I
• Crossing over


  The exchange of genetic material between non-sister chromatids during prophase I of meiosis, resulting in new combinations of alleles in daughter cells
• Map units


  A measure of the distance between two genes on the same chromatid
• Recombinant chromosome


  A chromosome which is not identical to one of the homologous chromosomes in a diploid cell
• Parental chromosome


  A chromosome which contains the same combination of alleles as one of the parents’ chromosomes
• Pedigree chart


  A diagram showing the expression of a trait over multiple generations
• Consanguineous breeding


  Breeding of two individuals that are closely related, also known as inbreeding
• Carrier


  An organism that has inherited a copy of a recessive allele for a genetic trait but does not display the trait due to it being masked by the presence of a dominant allele