The trait of an organism is determined by the combination of its alleles. Alleles are different variants of a gene, and an organism inherits two copies of each gene, one from each parent. These alleles can be dominant or recessive, and the particular combination of dominant and recessive alleles determines the phenotype or the physical characteristics or traits of the organism. The number of copies of the gene (other than the two copies inherited from the parents) generally does not determine a specific trait, although it may affect the expression or intensity of the trait.
