What does the term 'genotype' refer to?

The term 'genotype' specifically refers to the genetic makeup of an organism, particularly the combination of alleles present at specific loci in its DNA. This genetic composition determines potential traits and characteristics, although not all traits may be expressed due to environmental influences or interactions with other genes.

Understanding the genotype is crucial as it provides the foundational blueprint from which the phenotype— the observable traits—arises. While the phenotype can be influenced by environmental factors as well as the genotype, the genotype itself is purely about the underlying genetic instructions.

Other choices address different biological concepts. Observable traits relate to the phenotype, which is influenced by the genotype but is not synonymous with it. The dominant gene within a pair of alleles pertains specifically to the dominant allele's expression rather than the overall genetic makeup. Lastly, the total number of chromosomes refers to the chromosomal count in the organism's cells, which does not specify the combinations of alleles that define the genotype. Thus, the correct focus on the combination of alleles highlights the essential aspect of what genotype entails in genetics.