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Biology? Help in Genetics?????

A test cross was made between two Alaskan malamutes, a dominant phenotype for normal size and a homozygous recessive dwarf. Which of these results would indicate that the normal-sized dog is heterozygous?

a.) All puppies were phenotypically dominant.

b.)All puppies were phenotypically recessive.

c.) Some puppies were phenotypically dominant and some were recessive.

d.) none of the above.

Answers (5)

jasonwhitef89 profile image
0eb2zr0gaa profile image

If the normal-sized dog is heterozygous the puppies could be either normal-sized or dwarf (statistically 50/50), so they could be a or b or c. However, if all the puppies were normal-sized the parent could be either homozygous or heterozygous, so only a result of b or c would give an indication of heterozygosity.

aa11795477 profile image


A test cross is an unknown crossed with a homozygous recessive. If the offspring are 50% dominat and 50% recssive, you know your unknown was heterozygous.

eazz7jocaa profile image

C -

Say the dwarf is ss.

If you get some Ss, and some ss, it means the normal one has to have one S and one s, so its Ss.

ew5obytiaa profile image