A haploid strain of the Aspergillus nidulans carried the auxotrophic met-eight mutation conferring a requirement for methionine. Several million asexual spores were placed on minimal medium, and two prototrophic colonies grew and were isolated. Such prototrophs were crossed sexually with two dissimilar strains, with the progeny shown in body of following table, where met+ means that methionine isn’t required for growth and met- means that methionine is needed for growth.
Crossed with: Prototroph 1:
Prototroph 2:
a) Describe the origin of both of original prototrophic colonies.
b) Discuss the results of all 4 crosses, by using clearly defined gene symbols.