In mice, a short-tailed mutant was discovered. When it was crossed to a normal long-tailed mouse, 4 offspring were short-tailed and 3 were long-tailed. Two short-tailed mice from the F1 generation were selected and crossed. They produced 6 short-tailed and 3 long-tailed mice. These genetic experiments were repeated three times with approximately the same results. Part A Indicate whether short tail would be dominant or recessive.

Question

Malia Mcintyre

Biology

1 December, 20:42

In mice, a short-tailed mutant was discovered. When it was crossed to a normal long-tailed mouse, 4 offspring were short-tailed and 3 were long-tailed. Two short-tailed mice from the F1 generation were selected and crossed. They produced 6 short-tailed and 3 long-tailed mice. These genetic experiments were repeated three times with approximately the same results. Part A Indicate whether short tail would be dominant or recessive.

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Answers (1)

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Koen Bradshaw · Answer 1

Dominant

Explanation:

Let the allele for short tail trait be represented by "T" and allele for long tail trait be represented by "t"

When a short tailed mutant with genotype "tt" is mated with long tailed mouse, following offspring will be produced -

Tt * tt

Tt, Tt, tt, tt

so the ratio of short tailed and long tailed mouse is 1:1

Here it is given as 4:3. Hence, there are chances that short tail trait is dominant

In the second generation, two short tailed mouse are crossed. The following offspring will be produced

Tt * Tt

TT, Tt, Tt, tt

The ration of short tailed and long tailed mouse is 3:1

Here it is given as 6:3 i. e 2:1. Hence, short tail trait is dominant over long tail trait.