* Gene Locus: Imagine a library with shelves. Each shelf represents a specific chromosome, and each book on the shelf represents a gene. The gene locus is the specific address or location of a gene on a chromosome. Think of it like the call number of a book.

* Allele: Now, consider a particular gene, like the one for eye color. You have two copies of this gene, one inherited from your mother and one from your father. These copies might be slightly different, like two editions of the same book. Each version of the gene is called an allele.

Here's the relationship:

* A gene locus is the address of a gene on a chromosome.

* Alleles are the different versions of a gene at that specific locus.

Example:

* Gene locus: Let's say the gene for eye color is located on chromosome 15. This location is the gene locus.

* Alleles: At that locus, you might have one allele for brown eyes and one allele for blue eyes.

In summary:

* A gene locus is the physical location of a gene on a chromosome.

* Alleles are the alternative forms of a gene that exist at a specific locus.