A lizard with a striped tail and a normal head is crossed with one having a normal tail and a spotted head. All of the F1 progeny are normal (no stripes or spots). What progeny would be expected to be produced by mating the F1 progeny with each other, if the genes conferring stripes and spots were on different chromosomes?

The correct answer would be -9 normal : 3 striped : 3 spotted : 1 striped and spotted.

Explanation:

As the F1 progeny have no stripes or spots considered as normal, it means normal head and normal tail are dominant on their alternative traits. So, it is clear that the F1 progeny are heterozygous for both of the traits.

Henece the cross between the two F1 progeny is dihybrid cross of hetrozygous lizards which produces offspring in 9:3:3:1 ratio, where 9 are normal, 3 striped (dominant in one character), 3 spoted (dominant in other) , and 1 will be stripped and spotted (recessive).

Thus, the correct answer is - 9 normal : 3 striped : 3 spotted : 1 striped and spotted.

      n

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.