The System to Ascertain the X:A Ratio Involves Interactions Between

Question

The system to ascertain the X:A ratio involves interactions between which of the following?
A) Maternally synthesized proteins that have been deposited in the egg cytoplasm, and embryonically synthesized proteins that are encoded by several X-linked genes
B) Embryonically synthesized proteins that have been deposited in the egg cytoplasm and maternally synthesized proteins that are encoded by several X-linked genes
C) Paternally synthesized proteins that have been deposited in the sperm cytoplasm and embryonically synthesized proteins that are encoded by several X-linked genes
D) Embryonically synthesized proteins that have been deposited in the sperm cytoplasm and paternally synthesized proteins that are encoded by several Y-linked genes
E) None of these are correct.

Accepted Answer

The X:A ratio is determined by the interaction between maternally synthesized proteins that have been deposited in the egg cytoplasm and embryonically synthesized proteins that are encoded by several X-linked genes. Specifically, the ratio of X chromosomes to the number of autosomes present in the embryo determines the amount of protein produced by the X-linked genes, which ultimately determines the developmental pathway of the embryo.