In diploid cells, chromosomes come in pairs. These pairs of chromosomes are called homologous chromosomes.
Homologous chromosomes are not identical. They carry different alleles (versions) of the same genes.
An individual inherits one chromosome in each homologous pair from either parent.
In a pair of homologous chromosomes, one chromosome may carry the allele for brown eyes while the other carries the allele for blue eyes.
Genes on a pair of homologous chromosomes lie on the same locus (plural loci). This means that the two genes occupy the same position on both chromosomes.
Important! The sex chromosomes X and Y are not homologous. They do not contain the same genes.