Here's a breakdown:

* Genes: Units of heredity that determine specific traits. They are made up of DNA (deoxyribonucleic acid).

* DNA: A long, complex molecule that contains the genetic instructions for an organism.

* Chromosomes: Thread-like structures located inside the nucleus of cells. They are made up of tightly coiled DNA and proteins. Each chromosome carries many genes.

So, to summarize: Genes are located on chromosomes, which are made up of DNA.