Chromosomes resemble a string of beads with the beads being individual genes and the location of each gene along the chromosome is known as the locus. The locus is a fixed point where an individual gene will always be located on that chromosome. There are estimated to be tens of thousands of genes on each chromosome. Each individual gene determines a particular characteristic of the hamster such as shape, colour, coat, etc.
Individual mutant genes are symbolised with a letter or combination of letters. The use of a capital letter indicates that the gene is dominant and lower case indicates that the mutant gene is recessive. This symbolisation is a form of shorthand for working with genetics.