Genes = A segment of DNA

Genes are a segment of DNA which codes for the production of a specific trait such as:

Eye colour, or

Height

It depends on which gene you are discussing.

Memory aid depicting genes and segments

An orange segment wears jeans (genes).

Example

Magnification of a chromosome located in the nucleus of a cell

Further magnifications of inherited chromosomes from mother and father

NOTE:

A gene segment on a chromosome is often represented in diagrams by bands of colour around the chromosome, see below:

A signature of genes of a chromosome segment