Allelic interactions Flashcards
What is the F2 phenotypic ratio seen for a typical monohybrid cross with complete dominance?
3:1
What is the F2 phenotypic ratio seen for a typical dihybrid cross with complete dominance?
9:3:3:1
What is haplosufficiency? What kind of allelic interaction has this?
When one allele is sufficient to have that phenotype show. The heterozygote will have the same phenotype as the homozygote for that allele. This is occurring for complete dominance
What is haploinsufficiency? What kind of allelic interaction has this?
When a single allele isn’t enough for that phenotype to show, rather the heterozygote will be a blend of the two alleles. This occurs for incomplete dominance
What is the F2 phenotypic ratio seen for incomplete dominance in a monohybrid cross?
1:2:1
What is the F2 phenotypic ratio seen for codominance in a monohybrid cross?
1:2:1
Which allele is dominant when traits are codominant?
Neither one is dominant over the other, so they both show
What is the F2 phenotypic ratio seen for a lethal allelic interaction in a monohybrid cross?
2:1. The homozygous dominant die early in embryonic development
How do we define what sort of interaction certain alleles have?
Defined with respect to a single specific phenotype
How do allelic interactions work when there are multiple alleles?
A diploid individual can’t have more than 2 alleles at a time, but they all might interact differently
What are the 3 alleles for human blood type?
IA, IB, i
What is the allelic interaction between IA and i?
Complete dominance
What is the allelic interaction between IB and i?
Complete dominance
What is the allelic interaction between IA and IB?
Codominance
