l. ExTEND YouR UNDERSTANDING wITH ADDITIONAL TRC PROBLEMs Total fingerprint ridge count exemplifies a polygenic inheritance Penrose (1969) and others have suggested that a minimum of seven gene loci contribute to TRO, but a four-locus model is hypothesized in the problems that follow. Thus, AA represents the genotype for maximum ridge count and dabbccda symb the genotype for the minimum ridge count. that each active allele adds 15 ridges to the TRO of the male and 12 to the TRO female genotype aabbccdd produces a baseline TRC of 7o for males and 50 and that having the for females.