Question

Freckles are dominant to no freckles. Two people who have freckles and are heterozygous marry. What are the genotypes and phenotypes of all the offspring? Use F and f.

Answer 1

Gene coding the Freckles have Two allele .They are F and f.

F allele is dominant over the f allele and it is coding for Freckles .

f is the recessive form which is only expressed in homozygous recessive form

dominant homozygous --->FF

Dominant heterozygous --->Ff

Recessive homozygous --->ff

Here the both parent are having freckles and they are Heterozygous.So the genotype of the father and mother are "Ff"

Crossing Father and mother

Ff X Ff

Punnett square

	F	f
F	FF	Ff
f	Ff	ff

Genotype of the offsprings are FF : Ff :ff = 1:2 :1

1 offspring will Homozygous dominant

2 offspring will be Heterozygyous

1 offspring will be Homozygous recessive

Phenotype are Freckles :no freckles = 3:1

75% of the offsprings will be having freckles and 25% of the offspring will not have freckles.