Zygosity refers to the genetic condition of a zygote. In genetics, zygosity describes the similarity or dissimilarity of DNA between homologous chromosomes at a specific allelic position or gene. Every gene in a diploid organism has two alleles at the gene's locus. These alleles are defined as dominant or recessive, depending on the phenotype resulting from the two alleles. If a gene's two alleles are both dominant or both recessive, that specific gene is homozygous. If one allele is dominant a… (More on Homozygous)