Genes which are located nearer to each other in chromosome and are not separated during crossing over are called linked genes. They are more likely to be inherited together during meiosis.
When two genes are located nearer to each other on the same chromosome, they do not get separated during crossing over and move as a single entity. Since, they are not separated into chromatids, they do not assort with other alleles and thus recombinant or new combination of alleles are not formed. Therefore, when two genes are located nearer to each other, chances of separation become low and thus frequency of recombination is low. More closer the genes are present, lower will be the frequency of recombination.