In Aspergillus, the genes y (yellow), os (osmotic), c (colonial), leu (leucine-requiring), and a (aconidial) are located on the long arm of chromosome 3. A diploid was made between a haploid wild type and a haploid of genotype y os c leu a. From the green diploid, yellow diploid sectors appeared. When these were sampled and tested, the following was found:
56%were yellow, osmotic, aconidial, and leucine-requiring 40%were yellow, osmotic, colonial, aconidial, and leucine-requiring 4%were yellow, aconidial, and leucine-requiring
(a) What is the origin of the three types of yellow sectors? (Diagram it on chromosomes)
(b) What is the order and relative map distances of the five loci?
Help is given.
Whenever you have a diploid organism (expecially one that is usually haploid) you will often get expression of only one of the chromosomes at a time. But this can vary from one portion of the organism to another, (or in different organisms in a group). This is a little different than doing a cross and looking at the progeny.
So, let's start with part (b) because it's really the main answer. ...
This job explains diploid organisms. The diagram for linkages are provided.