Final answer:
The correct answer is d. the genes are probably located close to each other. Linked genes on the same chromosome tend to be inherited together unless separated by crossing-over, with closer genes being less likely to be recombined. Genetic mapping helps illustrate the relationships and distances between these genes.
Step-by-step explanation:
If two genes are on the same chromosome and rarely assort independently, the answer is d. the genes are probably located close to each other. This occurs because the proximity of genes on a chromosome affects their likelihood of being recombined during crossing-over. Crossing-over can occur at various locations on a chromosome, but the closer together two genes are, the less likely they are to be separated by this process.
Linkage is the term used to describe genes that are located on the same chromosome and tend to be inherited together unless crossing-over separates them. When genes are linked and close together, the parental genotypes are often preserved in the offspring, leading to a higher frequency of inheriting these genes together. In contrast, genes that are further apart on the chromosome have a higher probability of being separated by crossing-over, which results in a greater variety of genetic combinations.
Geneticists have been able to construct genetic maps by measuring the proportion of recombinant gametes, which indicates the relative distances between genes. These maps are useful for understanding how genes are arranged on chromosomes and can predict the likelihood of genes being inherited together or separately.