Under the genetic maternal effect, the phenotype of the offspring will express ?
A its own genotype
B the genotype of the mother
C the genotype of the offspring
D the genotype of the fater
The correct answer and explanation is:
The correct answer is B: the genotype of the mother.
The genetic maternal effect refers to the phenomenon where the phenotype of the offspring is determined by the genotype of the mother, rather than the genotype of the offspring itself. In this effect, the mother’s genetic makeup influences the development of the offspring, often through factors like proteins, RNA, and other molecules that the mother provides to her offspring during development. These molecules are typically deposited in the egg prior to fertilization and have a significant role in the early stages of development, such as the regulation of gene expression or the determination of body axes.
For example, in certain organisms like snails and some insects, the mother can pass on mRNA and proteins that affect the way the embryo develops. These maternal factors can lead to traits in the offspring that may not directly reflect their own genetic inheritance but instead reflect the contributions made by the mother’s genotype. A well-known example is the pattern of coiling in snails, where the direction of the coil (right or left) is determined by the mother’s genotype, not the offspring’s own genotype.
This maternal influence typically operates in the early developmental stages and may not be visible in the offspring once they mature. It’s important to note that the genetic maternal effect is different from other genetic inheritance patterns, such as Mendelian inheritance, where an offspring’s phenotype is primarily determined by its own genotype, inherited equally from both parents. In maternal effect inheritance, however, the mother’s genotype has a direct, albeit temporary, impact on the offspring’s phenotype.