Question

Crossing over plays a critical role in increasing the genetic variation among offspring of sexual reproduction. It is important to understand how crossing over occurs and its consequences in meiosis. Look carefully at the diagrams depicting different stages in meiosis in a cell where 2n = 6. Assume that the red chromosomes are of maternal origin and the blue chromosomes are of paternal origin.

Drag the name of the appropriate stage of meiosis to the target above each diagram. Then, in the pink target below each diagram, specify whether the configuration of the chromosomes related to crossing over is possible or impossible/unlikely. Note that the diagrams are in no particular order.

Answer 1

a) anaphase II

b) metaphase II

c) prophase I

d) metaphase I

e) impossible/unlikely

f) impossible/unlikely

g) possible

h) impossible/unlikely

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Answer 2

Answer: Prophase 1

Explanation: Crossing over BEGINS in Prophase 1, but tetras are aligned at the "equator" in Metaphase 1.