Three genes with recessive mutant phenotypes are located on thesame chromosome in maize: short stem (ss), purple aleurone(pr), and knotted leaf (kn). A plant with allthree mutant phenotypes is crossed with a true-breeding, wild-typeplant. Resulting F1 plants are then backcrossed to the parentalmutant line to produce the following progeny:Â Â (7 points)
Short       Purple    Knotted      Number
ss                      +                kn                 2342
+                       pr               +                  2297
ss                      pr               kn                 4095
+Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 3963
+                       +                kn                 979
ss                      pr               +                  992
ss                      +                +                  77
+                       pr               kn                 75
       Â
        A.  Howmany non-recombinant progeny were identified?
        B.  Howmany of the F2 plants contained a crossover between the short stemand knotted leaf genes?
        C.  Draw a chromosome map with the correct distances (rounded to onedecimal point) noted                                         between adjacent pairs ofgenes.
        D.  What is the gene order and arrangement of alleles for the P and F1plants used in these crosses?