A genotype refers to the genetic makeup of an organism, specifically the alleles it possesses for a particular trait. It is the combination of genes inherited from both parents that determines various characteristics, such as eye color or height. Genotypes are often represented using letters, where uppercase letters indicate dominant alleles and lowercase letters indicate recessive alleles. Understanding genotypes is essential in fields like genetics and biology, as they help explain how traits are passed down through generations. For example, in the study of Mendelian inheritance, scientists analyze the genotypes of organisms to predict the likelihood of certain traits appearing in offspring.