AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

FORKED LINE METHOD

• The other method for determining the outcome of a cross is the forked line or branch diagram method which is based on phenotypic rather than genotypic distributions.
• The forked line method is especially useful when three or more characteristics are crossed simultaneously.
• Each branch point represents the expected distribution of phenotypes at a particular locus.
• To determine the overall probability of a particular phenotype, all of the probabilities along a particular line are multiplied.
• Example for a dihybrid crosses:
  • Round and Yellow (RRYY) are dominant over Wrinkled and Green (rryy) respectively.
  • Selfing of the F_1.