A maternal effect can cause the offspring phenotype ratio to depart from that of classic Mendelian inheritance. In a species of
snail, the dominant allele N codes for right-handed shell coiling and recessive allele n codes for left-handed shell coiling. If an Nn female with right-handed shell coiling males with an Nn male, what is the shell coiling phenotypic ratio of their offspring?
a. 4 right-handed coil:0, left-handed coil
b. 3. Right-handed coil: 1.left-handed coil
c. 3.bidirectional coil: 1.left-handed coil
d. 0.right-handed coil: 4.left-handed coil
a. 4 right-handed coil:0, left-handed coil
b. 3. Right-handed coil: 1.left-handed coil
c. 3.bidirectional coil: 1.left-handed coil
d. 0.right-handed coil: 4.left-handed coil
1 answer:
Response:
A) 4 right-handed coils: 0 left-handed coil
Clarification:
Referring to the MENDELION CROSS:
We can observe NN, Nn, Nn, nn
NN, Nn, and Nn represent the 3 instances of right-handed coiling while nn denotes left-handed coiling.
In the case of shell coiling in snails, maternal inheritance plays a role, where the phenotype alone determines the offspring's traits.
Maternal traits: Since the female parent possesses right-handed shell coiling, all offspring will inherit this characteristic.
Thus, the observable phenotypic ratio is:
4 Right-handed coils: 0 Left-handed coils
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