Questions -

Q1. You make a cross between two completely homozygous lines (line A and line B)

Assume A and B differ at 6 loci that segregate independently.

Assume each F₁ plant produces 10,000 F₂ seed.

How many F₁ seed will you need for A x B in order to have a large enough F₂  population to represent the cross? 

a) 36 seed

b) 1 seed

c) 128 seed

d) 2 seed

e) 6 seed

Q2. You make a cross between two completely homozygous lines (line C and line D).

Assume A and B differ at 7 unlinked loci.

Assume that an F₁ plant produces 150 seed.

How many F₁ seed will you need for C x D to produce a large enough F₂ population to represent all the possible genotypes?

a) 50 seed

b) 14 seed

c) 110 seed

d) 1 seed

e) 196 seed

Q3. You make a cross between A x B.  Again, assume A and B differ by genes at 6 unlinked loci.

You make a top cross with another completely homozygous line C to construct the three-way cross A/ B//C. 

Assume C does not increase the number of segregating loci and that each three-way cross F₁ plant produces an infinite amount of F₂ seed.  Hence the of size of the F₂ population is not a concern.

How many F₁ seed will you need for A/B//C?

a) 1 seed

b) 2 seed

c) 6 seed

d) 64 seed

e) 128 seed

Q4. You make a cross between A x B.

Again assume A and B differ by genes at 6 loci.

You make a top cross with another completely homozygous line C (Final cross is A/B//C).

Again assume C does not increase the number of segregating loci.

This time, assume each top-cross F₁ plant produces 250 F₂ seed.

How many F₁ seed will you need for A/B//C to completely represent the population?

Consider F₂ population size in your calculation.

a) 64 seed

b) 16 seed

c) 47 seed

d) 128 seed

e) 256 seed

Q5. You make a cross between C x D, with another completely homozygous line F (Final cross is (C/D//F).

Again, assume C and D differ by genes at 7 unlinked loci.

Assume F increases the number of segregating loci by 2 new unlinked loci (C and D were homozygous and similar at these two loci).

Assume that each F₁ plant produces 250 F₂ seed.

How many F₁ seed will you need for C/D//F? Consider the F₂ population size.

a) 164 seed

b) 1049 seed

c) 128 seed

d) 262144 seed

e) 512 seed