In fish of the species Perissodus microlepis, some individuals have mouths that open to the right and some individuals have mouths that open to the left. The direction of the mouth opening is a genetic trait controlled by a single gene. The allele for aright-opening mouth® is dominant to the allele fora left-opening mouth®. If two fish heterozygous for the mouth trait are crossed, what is the expected ratio of phenotypesin the offspring?

A 1 right-opening mouth : 3 left - opening mouth

B 2 right-opening mouth : 2 left - opening mouth

C 3 right-opening mouth : 1 left - opening mouth

D 4 right-opening mouth : 0 left - opening mouth

Question

Biology

Abbie Delgado

17 September, 04:56

In fish of the species Perissodus microlepis, some individuals have mouths that open to the right and some individuals have mouths that open to the left. The direction of the mouth opening is a genetic trait controlled by a single gene. The allele for aright-opening mouth® is dominant to the allele fora left-opening mouth®. If two fish heterozygous for the mouth trait are crossed, what is the expected ratio of phenotypesin the offspring?

A 1 right-opening mouth : 3 left - opening mouth

B 2 right-opening mouth : 2 left - opening mouth

C 3 right-opening mouth : 1 left - opening mouth

D 4 right-opening mouth : 0 left - opening mouth

+2

Answers (1)

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Timothy Mcneil · Answer 1

C

When crossing two heterozygous individuals for a dominant and recessive gene, the phenotypes (phenotypes!) are almost always 3 dominant to 1 recessive.

If ur not sure, make a Puneet square. You'll get.

P p

P PP Pp

P Pp pp