Phenotype is the physical expression of the genotype. Sperm and unfertilized eggs are haploid. Most of the Y chromosome is considered haploid. Somatic cells are diploid in humans. One from the father and one from the mother.
Linkage requires minimally that the two loci be on the same chromosome.
Genotype More than one gene may affect a trait. This is called a polygenic trait. When one gene affects multiple traits, we call this pleiotropy . If multiple genes affect the trait, the genotype consists of all loci that affect that trait. Genotypes Note that two organisms with the same phenotype may have different genotypes.