Recombination is a process that results in genetic exchange between chromosomes or chromosomal regions. Cells and organisms with pairs of homologous chromosomes are called diploid. Meiosis involves the intimate pairing of homologous chromosomes and recombination between them. Genetic testing identifies changes in chromosomes, genes, or proteins. Multifactorial systems involve rearrangements of sex chromosomes and autosomes. The first subgroup consists of seven genes that map to six different chromosomes. A numerical hybrid results from the fusion of gametes having different haploid numbers of chromosomes. The process of pairing the homologous chromosomes is called synapsis. All animals have a set of DNA coding for genes present on chromosomes. The majority of eukaryotic genes are stored on a set of large, linear chromosomes. Women have two homologous sex chromosomes (XX). Cumin is a diploid species with 14 chromosomes (i.e. 2n = 14). DNA usually occurs as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. Maize is a diploid with 20 chromosomes (n=10). It synthesizes telomeres at the ends of chromosomes.