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?