The Maternal Effect in Lymnaea Is Such That the Genotype

question 5

Multiple Choice

The maternal effect in Lymnaea is such that the genotype of the egg determines the direction of shell coiling regardless of the genotype of the offspring.Apparently,the cause of this spectacular maternal effect results from ________.

• A) orientation of the spindle apparatus in early cleavage
• B) genophores present in the egg cytoplasm
• C) the F factor exerting its influence on the centrosome
• D) colicins "poisoning" one of the cleavage centers
• E) allelic substitution as demonstrated from RNA injection experiments

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Definitions:

Sacral

Relating to the sacrum, the triangular bone at the base of the spine formed from fused vertebrae.

Calcitonin

A hormone produced by the thyroid gland that helps regulate blood calcium levels.

Thymus Gland

A primary lymphoid organ located in the upper anterior part of the chest cavity, involved in the maturation of T lymphocytes (T cells).

Insulin

A hormone produced by the pancreas that regulates blood sugar levels by facilitating the uptake of glucose into tissues.