Genetic mapping is a way to identify exactly which chromosome has which gene and exactly pinpointing where that gene lies on that particular chromosome. Mapping also acts as a method in determining which gene is most likely recombine based on the distance between two genes. The distance between two genes is measured in units known as centimorgan. A centimorgan is a distance between genes for which one product of meiosis in one hundred is recombinant. The further two genes are from each other, the more likely they are going to recombine. If it were closer, the opposite would occur.