What term describes the genetic makeup of an organism indicated by its alleles?

The term that describes the genetic makeup of an organism indicated by its alleles is "genotype." The genotype encompasses the specific set of genes and alleles that an individual possesses, which can influence various traits and characteristics. It provides the underlying genetic basis for the phenotypic expression observed in an organism, but does not refer to the observable traits themselves, which would be described as the phenotype. This distinction is essential in genetics, as it allows one to differentiate between the genetic information (genotype) and the physical manifestations of that information (phenotype).

The concept of a gene pool refers to the total collection of genes and alleles within a population, which is broader than an individual organism's genotype. Meanwhile, a Mendelian population is a specific group that shares a common set of genes, but again does not focus on the genetic makeup of individual organisms. Therefore, understanding the term "genotype" is crucial when discussing the genetic aspects of biology and anthropology.