One of the possible forms of the same gene, containing information about a specific variant of the development of a trait, is located in the same regions (loci) of homologous chromosomes. In each cell of the body (except for the sex cells) there are usually two alleles of each gene – one from the mother, the other from the father. The germ cells (gametes) of an organism contain only one allele of each gene, rather than two, as in ordinary somatic cells, since germ cells are haploid and contain only one set of chromosomes.