Final answer:
The marker closest to a factor causing testicular cancer is the bb genotype.
Step-by-step explanation:
The marker closest to a factor causing testicular cancer can be determined by looking at the genotypes and phenotypes of the different markers. In this case, the genotypes and phenotypes given are:
AA healthy: 1228, diseased: 217
Aa healthy: 434, diseased: 76
aa healthy: 38, diseased: 7
BB healthy: 1115, diseased: 10
Bb healthy: 560, diseased: 190
bb healthy: 25, diseased: 100
CC healthy: 1143, diseased: 202
Cc healthy: 502, diseased: 88
cc healthy: 55, diseased: 10
DD healthy: 612, diseased: 108
Dd healthy: 816, diseased: 144
dd healthy: 272, diseased: 48
From these data, we can see that the marker with the most significant difference between healthy and diseased individuals is the bb genotype. In the healthy group, there are 25 individuals with the bb genotype, while in the diseased group, there are 100 individuals with the bb genotype. This suggests that the bb genotype may be closest to a factor causing testicular cancer.