Answer:
The number of linked genes, which are common to the group.
Step-by-step explanation:
A gene map signifies towards a chromosomal map, which illustrates the spatial organization of genes on a chromosome. The genes, which are situated on distinct chromosomes or, which are situated far away on the similar chromosome are illustrated as unlinked genes, while the genes that are near to each other on the similar chromosomes are considered to be linked.
The linkage maps are formed by determining recombination frequency for many pairs of genes. The linkage maps demonstrate the order and relative distance of the genes on the chromosome. In order to form a linkage map for an array of organisms, the scientists have to predict the number of linked genes, which are common to the group.