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Crossing Over in Sordaria

APBIO-2KQ1F4

"Fcpage05." Fcpage05. N.p., n.d. Web. 05 Mar. 2016. http://www.virofond.ulg.ac.be/Collectif/fcpage05.htm.

The fungus Sordaria fimicola exchanges genetic material when two mycelia meet and fuse. The resulting zygote undergoes meiosis and then mitosis to produce asci. Each ascus contains eight haploid spores. A single gene determines the spore color.

A cross was made between black and tan strains. The resulting asci are shown above.

Which of the following can be concluded from the pattern of the spores seen in the picture?

A

A pattern of four black and four tan spores in a row (4:4 pattern) is consistent with crossing over.

B

A pattern of 2 tan: 4 black: 2 tan spores in a row is consistent with non-recombinant events.

C

A pattern of 2 tan: 2 black: 2 tan: 2 black would indicate crossing over occurred.

D

All spore patterns would show meiosis has occurred during Prophase I.