17.2 - Dihybrid Inheritance Flashcards
What a dihybrid cross is An example of dihybrid inheritance in pea plants Reasons for deviations from expected ratios
What is a dihybrid cross?
Show the simultaneous inheritance of two genes controlling separate characteristics
How is genotype written in a dihybrid cross?
Alleles for one gene followed by alleles for the second gene
What are the uses of dihybrid crosses?
Determine gene linkage
What is the law of independent assortment?
Alleles for different genes segregate independently
What are the four phenotypes in pea plant dihybrid inheritance?
Yellow round
What is a true breeding organism?
Homozygous for studied traits
What are the steps for setting up an F1 dihybrid cross?
Mate homozygous individuals
What happens in an F1 dihybrid cross between homozygotes?
All offspring have identical phenotypes and genotypes
What is the typical F2 phenotypic ratio in a dihybrid cross?
9:3:3:1
What are reasons for deviations from expected ratios?
Random fertilization
How does random fertilization affect ratios?
Small samples lead to skewed ratios
How do linked genes affect ratios?
Alleles inherited together unless crossing over occurs
