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Key concept: genetic linkage

When 2 genetic loci or alleles of genes are physically near each other on a chromosome, they are more likely to be inherited together. By looking at how frequently they are inherited together rather than separately among a set of offspring from a cross, we can calculate how closely linked they are to one another.

In marker-assisted breeding, keep in mind that the marker and the gene for the trait of interest may not be at exactly the same locus, but tightly linked (very close together). We will discuss this further in the mapping and QTL sections.