 The probability of chromosomal crossover occurring between two given points on the chromosome is related to the distance between the points . For an arbitrarily long distance , the probability of crossover is high enough that the inheritance of the genes is effectively uncorrelated . For genes that are closer together , however , the lower probability of crossover means that the genes demonstrate genetic linkage ; alleles for the two genes tend to be inherited together . The amounts of linkage between a series of genes can be combined to form a linear linkage map that roughly describes the arrangement of the genes along the chromosome . 
