In genetics, what are homozygous and heterozygous genes, and are they alternate for each other?
There were actually three different genes questions at the link you supplied. When an organism has two of the same genes for a trait, this condition is known as homozygous. When an organism has two different genes for a trait, this is called heterozygous. The alternate genes for a particular trait are called alleles. An example of various alleles for the same trait are the alleles for blood type. There is an allele for A, for B, and for O. The recessive allele is O and A and B alleles are codominant. So, for blood type, a person could be homozygous, if their gene combination is AA, BB, or OO. However, if a person has the gene combinations-- AO, BO or AB, they would be heterozygous for that particular trait.