Dihybrid inheritance

Question 1

What is dihybrid inheritance

Answer 1

How two characters, determined by two different genes located on different chromosomes, are inherited

Question 2

What two characteristics did Mendel experiment with research dihybrid inheritance

Answer 2

. He investigated the inheritance of two characters of a pea plant at the same time:
. Seed shape: Where round shape is dominant to wrinkled shape
. Seed colour, where yellow seeds are dominant to green ones

Question 3

What did Mendel do with the peas

What were the parental genotypes
What were the gametes

Answer 3

. He carried out a cross between the following two pure breeding types of plants:

. One always producing round, yellow seeds (both dominant features)
. One always producing wrinkled, green seeds (both recessive)

Genotypes were RRGG and rrgg
So gametes were RG and rg

So all the offspring produced were RrGg so were all round and yellow

Question 4

What did Mendel find in the F1 generation when breeding his seeds together

What were the results when he crossed them with each other

Answer 4

. He obtained plants all of which produced round, yellow seeds (all dominant features)
. Then he crossed two of these
so two RrGg made 4 types of gamete:

RG, Rg, rG, eg
So in a punnet square, this makes
9 round yellow seeds
3 round green seeds
3 wrinkled yellow seeds
1 wrinkled green seed

So ratio 9:3:3:1

Question 5

What would the gametes be in the parental genotype was RRGG

What if it was rrgg

What is it was RrGg

Answer 5

RG

rg

RG, rG, Rg, rg

Question 6

From Mendels results from dihybrid inheritance, what law did he come up with

Answer 6

Law of independent assortment:

Each member of a pair of alleles may combine randomly with either of another pair