dihybrid inheritance

Question 1

what does dihybrid inheritance show and when were the first experiments carried out?

Answer 1

dihybrid inheritance shows how 2 pairs of contrasting characteristics are inherited. again, the first experiments on this inheritance were carried out by Mendel on peas.

Question 2

in dihybrid inheritance, the two characteristics are _________ and assumed to be __ _________ _____ __ ___________

Answer 2

unrelated, on different pairs of chromosomes

Question 3

Purple flower (P) is dominant to white (p)
Tall (T) is dominant to dwarf (t)

pure breeding tall plants with purple flowers were crossed with pure breeding dwarf plants with white flowers. the resulting F1 generation were all found to be tall with purple flowers. when these were self crossed to produce an F2 generation, Mendel found that out of a total of 556 seeds, 315 were tall and purple, 101 were dwarf and purple, 108 tall and white and 32 dwarf and white. this was interpreted as a ratio of 9:3:3:1. this is known as the ________ _____.

draw a monohybrid cross and a dihybrid punnet square to show this

Answer 3

dihybrid ratio

see diagram

Question 4

what gametes will be produced from the following individuals?
AABB
AaBB
AaBb

Answer 4

AABB - AB
AaBB - AB aB
AaBb - AB Ab aB ab

Question 5

does a backcross also work for the dihybrid example?

Answer 5

as with the monohybrid examples, a backcross using a homozygous recessive allows identification of unknown genotypes. again expected ratios for the outcomes of each cross can be predicted.

Question 6

what happens when a sex linked disease is caused by a dominant allele?

Answer 6

some sex linked diseases are caused by a dominant allele. all female children of an affected father will also be affected in this case.