You are studying a plieotrophic gene in dogs. One trait governed by this gene is tail length. For this trait the T allele is associated with normal length tails and the t allele is associated with short tails. The other trait governed by T/t is viability. In this case, T is associated with normal growth and development; whereas t is associated with embryonic loss of viability. In both cases T is completely dominant to t. You cross two dogs that are Tt heterozygotes. What ratio of offspring do you expect to see as a result of this cross?

a. 3 dogs with short tails : 1 dog with normal tail
b. 2 dogs with normal tails : 1 dog with short tail
c. 3 dogs with normal tails : 1 dog with short tail
d. 2 dogs with short tails : 1 dog with normal tail
e. None of the above

Explanation: 1 dog will be homozygote TT (is homozygote for normal tail length), 2 dogs will be heterozygous Tt (is the gene for embryonic loss of viability with short taill will be recessive or masked by the dominant T. While 1 dog will be homoxygote gene for TT(homozygote gene for embryonic loss of viability with short still.

3 dogs will altogether have normal tail while one will have short tail.

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