1. (4 PTS) In humans the dominant allele N causes anabnormal shape of the patella in the knee (n is the normalallele).  A separate gene affects finger length, and thedominant allele B causes abnormally short fingers, whereasb gives normal length.   

            

A  study focused on people who have both abnormalpatellae and short fingers (they most likely have the genotypeN/n B/b).  They inherited the N allelefrom one parent and the B allele from the otherparent.

These N/n B/b individuals mated with normalspouses.  (The spouses had no history of abnormalpatellae or short fingers in their families; they can be assumed tobehomozygous        normal.)  40progeny were born; they are classified as follows:

                                     Normal                                                3

                                     Abnormalknees andfingers           2

                                     Abnormalkneesonly                     17

                                     Abnormalfingersonly                    18

            (a)Using the chi square test, determine whether there is significantlinkage between the B/b and the N/ngene.                                                                                

                         

                        

            (b)  Ifyou conclude there is linkage, what is the distance between the twogenes?