What defines a linkage group in genetics?

A linkage group in genetics is defined by all genes that are located on the same chromosome. This is significant because genes that reside on the same chromosome tend to be inherited together during meiosis, particularly if they are close together on the chromosome. The closer the genes are to each other, the less likely they are to be separated by recombination during crossover events in meiosis. This principle underlies the concept of genetic linkage and mapping of genes.

In contrast, genes on different chromosomes or those that can recombine freely do not fall under the definition of a linkage group. Independent inheritance of genes typically occurs when they are located on separate chromosomes or are far apart on the same chromosome, making them less likely to be inherited together due to recombination. Thus, defining a linkage group specifically involves the proximity of genes on a single chromosome, which highlights the concept of linkage in inheritance patterns.