Question

In a cross between homozygous recessive and a heterozygous dominant, the phenotypic and genotypic ratios respectively are ______

Options

• 1:1 and 1:1

• 3:1 and 1:1

• all are dominant phenotypes and all are dominant heterozygous genotypes

• all are recessive phenotypes and all are recessive genotypes

Answer 1

In a cross between homozygous recessive and a heterozygous dominant, the phenotypic and genotypic ratios respectively are 1:1 and 1:1.

Explanation:

Phenotypes:	Heterozygous dominant	×	Homozygous recessive
Genotypes: Gametes:		×
F1 generation:		t	t
	T	Tt	Tt
	t	tt	tt
Phenotypic ratio:		1:1	(Tall: Dwarf)
Genotypic ratio:		1:1	(Tt: tt)