The Rec8 protein holds sister chromatids together during meiosis. If an individual has a mutation that prevents degradation of Rec8, this would most likely prevent

Question

A.  normal segregation during meiosis I.
B.  normal segregation during meiosis II.
C.  synapsis of homologous chromosomes.
D.  crossing over during prophase I.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

  Gather Content
  · What do you know about meiosis? How does it relate to the question?
  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?  

  Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

B.  normal segregation during meiosis II.

Clarify Question
· What is the key concept addressed by the question?
        o The question asks about the role of Rec8 on chromatid separation.
· What type of thinking is required?
        o You are being asked to apply your knowledge of chromatids to predict what would happen if they could not separate.
· What key words does the question contain and what do they mean?
        o Rec8 protein holds sister chromatids together – Rec8 is part of the cohesin that holds sister chromatids together.  It needs to be degraded to allow sister chromatids to separate in anaphase II of meiosis

  Gather Content
  · What do you know about meiosis? How does it relate to the question?
        o In meiosis there are two stages, in meiosis I the chromosome pairs line up on the equator and separate.  Then in meiosis II the sister chromatids separate.
  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?
        o If the sister chromatids cannot separate this would happen in meiosis II and not meiosis I.
        o Rec8 is part of cohesin, it won’t be involved in crossing over or synapsis.

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?  
        o The best answer is that without being able to degrade Rec8 and cohesin the chromosomes will not be able to segregate normally during meiosis II.

  Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to apply your understanding of the role of Rec8 and cohesin to predict what would happen if it was inhibited during meiosis. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you recall that Rec8 was part of cohesin and holds sister chromatids together until it is degraded in meiosis II?  Did you think that the sister chromatids separate in meiosis I?  Did you think that Rec8 was involved in crossing over or the synapse instead of being part of cohesin?