Do genes that occupy a similar locus on the genome have correlated function, specifically in human beings? It is my understanding that adjacent genes are inherited together, and so location plays a role there. However it terms of function, I don't know to what extent location plays a role. Furthermore, if say two adjacent genes have the same expression, does this necessarily mean that their function is correlated, or is that interpretation stretch?
In bacteria, this is often true. This is because more than one gene is often transcribed onto a single RNA. This grouping of genes is called an operon. It is usually true that these have a related function because they are being translated to protein in very much the same proportion - a convenient way to regulate the function as a whole.
Once you get into eukaryotes this is no longer true (except for v. rare cases most of which are viral genes), one mRNA transcript contains just one translation region. This is true even for yeast and other single celled organisms. Gene regulation can be correlated, but the relationship on the genome has little to do with it.
There is some importance to the genomic relationship of two genes because of the crossing over that occurs in meiosis, but this is more of a relationship that is important in speciation and evolution, it doesn't have any recognized importance to how the genes act within the eukaryotic cell.
A group of tightly linked genes that are involved in similar molecular pathway is called a supergene.
For the pleasure to formulate a slight opposition to @shigeta's answer, I will give some examples of supergenes in eukaryotes.
- In Primula, heterostyly is controlled by a supergene.
- In Papilio memno, mimicry is controlled by a supergene.
- In some species of ants, some social behaviour is caused by a supergene.
- Sexual chromosomes (and this is quite common) can be considered as supergenes.
Globally speaking, every locus that is under antagonist sexual in different sex/castes/ecotype/whatever is likely to start forming a supergene as soon as another locus that has antagonist effect appears in its vicinity because the presence of two such genes on the same chromosomal region will select for arrest of recombination.
But of course, those represent exceptions (however common these exceptions might be) but in general, I don't think you should expect that adjacent genes would have similar functions.