Marbles is a Manx cat whose tail is so short that she appears not to have one.The genotype for short tail in Manx cats is heterozygous (Mm).Cats that are genotype mm have normal length tails,but cats that are genotype MM die before birth due to highly abnormal brains and spinal cords.Marbles has one copy of a dominant _____ allele.2-14-2013
A)pleiotropic
B)penetrant
C)lethal
D)polymorphic

Question

Quizplus · Accepted Answer

Marbles has one copy of the heterozygous genotype for the short tail trait in Manx cats, which is a dominant lethal allele. This means that if Marbles had two copies of the dominant allele (MM), she would not have survived past birth due to abnormal brain and spinal cord development. The other answer choices are not applicable in this scenario.

Marbles Is a Manx Cat Whose Tail Is So Short