Loss of the gene encoding shugoshin in many multicellular organisms leads to sterility, suggesting defects in meiosis. What would you expect to occur in meiotic cells lacking shugoshin?
A) The homologs fail to separate in anaphase I.
B) The sister chromatids fail to separate in anaphase II.
C) All chromatids separate prematurely in anaphase I.
D) Removal of cohesion between homolog arms fails in prophase I.
E) Removal of cohesion between sister chromatids fails in prophase II.

Question

Quizplus · Accepted Answer

In the absence of shugoshin, cohesin complexes at the centromeric regions are no longer protected from phosphorylation. The phosphorylated cohesin subunits are then cleaved by separase in anaphase I. Consequently, the sister chromatids segregate randomly in anaphase II.

Loss of the Gene Encoding Shugoshin in Many Multicellular Organisms