Which of the Following is NOT True Regarding Vertebrate Segmentation

Question

Which of the following is NOT true regarding vertebrate segmentation?
A) The presomitic mesoderm retreats tailward as new somites are generated.
B) The period of gene-expression oscillations in the presomitic mesoderm determines the size of each somite.
C) If feedback delays in the gene-expression oscillations are increased, somite size will consequently increase as well.
D) Notch-mediated lateral inhibition ensures that the segmentation clock is different in neighboring cells in the presomitic mesoderm.

Accepted Answer

A gene-expression oscillator acts as a clock to control segmentation in vertebrates. During this process, Notch signaling ensures that the oscillations are in synchrony in neighboring cells in the presomitic mesoderm (i.e. the segmentation clock is the same). Note that this is opposite to the role of Notch signaling in lateral inhibition.