3. Muliple Allele And Dihybrid Crosses

Question 1

How are multiple allele crosses different to monohybrid crosses?

Answer 1

Although they still only involve one gene.

The gene can have more than 2 alleles.

(Monohybrid crosses look at inheritance of one characteristic only)

Question 2

Example of multiple allele crosses.

Answer 2

ABO blood group in humans
I0 blood group O

IA blood group A

IB blood group B

IO is recessive

IA and IB are co dominant

Question 3

Dihybrid inheritance

Answer 3

Inheritance of 2 characteristics which are controlled by different genes.

Each of 2 genes has different alleles.

Question 4

Dihybrid crosses

Answer 4

Show likelihood of offspring inheriting certain combinations of 2 characteristics.

Question 5

What will a dihybrid cross between a homozygous dominant parent and homozygous recessive patent (RRYY and rryy) produce?

Answer 5

ALL heterozygous offspring in F2 generation

Question 6

What will a dihybrid cross with 2 heterozygous parents produce ?

Answer 6

9:3:3:1