Question

In tomato (Lycopersicon esculentum), the following genes are located on chromosome-4.

                        d - dwarf plant                        + - tall plant

                        m - mottled green leaf             + - uniform green leaf

                        p - pubescent fruit                   + - smooth fruit

                        A testcross of a triple heterozygote for the above characteristics gave the following results.

                        Phenotypes                                          No.      ________________________________________

                        Wild type                                            29

                        Pubescent fruit                                    1

                        Dwarf                                                  23

                        Mottled leaf                                        430

                        Mottled leaf, pubescent fruit               24

                        dwarf, pubescent fruit                         462

                        dwarf, mottled leaf, pubescent                           30

                        dwarf, mottled leaf                                 1                                                                                           _________________________________________

What is the correct gene sequence?

Which are the non-crossover progeny classes and which are the crossover progeny classes?

What are the distances between the genes? Draw a genetic map, indicating the position of loci.

What do you understand by the term interference? Is there interference and if so how much?

What would have been the genotypes and phenotypes of the original true-breeding parents and of the F₁ triple heterozygotes.

Answer 1