Final answer:
Linked genes are ones located on the same chromosome and are inherited together, unless separated by crossing-over during meiosis. The proximity of genes on a chromosome affects the likelihood of crossing-over and, therefore, the inheritance of linked traits. These relationships are depicted in linkage maps, which help geneticists understand genetic inheritance.
Step-by-step explanation:
Linked genes are genes that are found on the same chromosome. These genes tend to be inherited together because their alleles are close to each other on the chromosome and segregate together during the process of meiosis. This phenomenon occurs unless they are separated by a genetic mechanism called crossing-over which takes place during meiosis I. Crossing-over allows for the exchange of genetic material between homologous chromosomes, which can disrupt the linkage of the genes if they are not very close together on the chromosome. As a result, the closer two genes are to each other, the lower the likelihood that crossing-over will separate their alleles. Geneticists utilize the frequency of crossing-over events to construct linkage maps, which show the positions of genes on a chromosome.
Illustrating this concept further, imagine a dihybrid cross involving two linked genes, such as flower color and plant height. If the genes for tall plants and red flowers reside next to each other on one chromosome, while the alleles for short plants and yellow flowers are on the homologous chromosome, the gametes produced will carry the alleles in the same combinations as the parental genotypes. Consequently, in this scenario, the Mendelian 9:3:3:1 ratio expected for a dihybrid cross does not apply due to the phenomenon of linkage. However, if the genes are further apart, crossing-over is more probable and the genes can assort more independently, which is why linkage maps are invaluable tools for geneticists studying inheritance patterns.