Question

3. (2pts) A group of researchers working with Arabidopsis (a small weedy plant that is widely used as model organism by plant geneticists) is isolating new mutations that cause extra petals to be formed on the flowers. They isolate six plants from different mutagenesis experiments that all show the desired phenotype. They then establish true breeding strains A-F by self-fertilizing and further inbreeding the plants. They also established that the mutations in the strains were recessive, and gave a 3:1 (wildtype to extra petals) distribution in the F2 when mutants were crossed to wildtype and the F1 was crossed to itself. Crossing plants (transferring pollen to stigmata) from strain A to the other plants, the following results are obtained: Ax B: progeny all wildtype Ax C: progeny all have extra petals A x D: progeny all wildtype A x E: progeny all have extra petals. Ax F: progeny all wildtype a. Are any of the mutations isolated in the same gene? If so which ones? b. How would you proceed if you were interested in finding out how many different genes were identified in this mutagenesis experiment?

Answer 1

A. Strain A , C and E have same mutation because all the offsprings are mutated and that too with same mutation.

B. To identify the number of genes perform a complementation test i.e cross every individual with each other and then analyze the results.