Allelic interactions

Question 1

What is the F2 phenotypic ratio seen for a typical monohybrid cross with complete dominance?

Answer 1

3:1

Question 2

What is the F2 phenotypic ratio seen for a typical dihybrid cross with complete dominance?

Answer 2

9:3:3:1

Question 3

What is haplosufficiency? What kind of allelic interaction has this?

Answer 3

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

Question 4

What is haploinsufficiency? What kind of allelic interaction has this?

Answer 4

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

Question 5

What is the F2 phenotypic ratio seen for incomplete dominance in a monohybrid cross?

Answer 5

1:2:1

Question 6

What is the F2 phenotypic ratio seen for codominance in a monohybrid cross?

Answer 6

1:2:1

Question 7

Which allele is dominant when traits are codominant?

Answer 7

Neither one is dominant over the other, so they both show

Question 8

What is the F2 phenotypic ratio seen for a lethal allelic interaction in a monohybrid cross?

Answer 8

2:1. The homozygous dominant die early in embryonic development

Question 9

How do we define what sort of interaction certain alleles have?

Answer 9

Defined with respect to a single specific phenotype

Question 10

How do allelic interactions work when there are multiple alleles?

Answer 10

A diploid individual can’t have more than 2 alleles at a time, but they all might interact differently

Question 11

What are the 3 alleles for human blood type?

Answer 11

IA, IB, i

Question 12

What is the allelic interaction between IA and i?

Answer 12

Complete dominance

Question 13

What is the allelic interaction between IB and i?

Answer 13

Complete dominance

Question 14

What is the allelic interaction between IA and IB?

Answer 14

Codominance