Homozygous

Homozygous means that the genome of a cell has two identical alleles, i.e. two identical copies of a particular gene on the two chromosomes that contain the gene. A homologous chromosome is a chromosome that matches another chromosome in terms of the shape and sequence of genes.

Heterozygosity is the heterozygosity in relation to a genetic trait. An individual with two sets of chromosomes (diploid) is heterozygous or heterozygous with respect to a characteristic if a gene in these sets of chromosomes is present in two different expressions (alleles).