Homozygous organisms have two identical alleles for a trait. They may have two copies of dominant alleles or two copies of the recessive allele of a gene. For example, both RR and rr are homozygous genotypes. However, a heterozygous or hybrid genotype has one dominant and one recessive allele for a gene. Here, "Rr" genotype would be an example of hybrid or heterozygous genotype.
