A homologous chromosome pertains to one of a pair of chromosomes with the same gene sequence, loci, chromosomal length, and centromere location. A homologous pair consists of one paternal and one maternal chromosome. In humans, there are a total of 46 chromosomes in the nucleus of a somatic cell. Half of them (22 autosomes + X or Y chromosome) are inherited from the father and the other half (22 autosomes + X chromosome), from the mother. Each maternal chromosome has a corresponding paternal chromosome; they pair up during meiosis. Typically, a female will have 23 homologous chromosomes whereas a male will have 22. That is because the sex chromosomes, X and Y, in males are not homologous. The pairing up of homologous chromosomes during meiosis is important to promote genetic variation. Because of the genetic recombination that occurs between homologous pairs at meiosis, the resulting haploid gametes contain chromosomes that are genetically different from each other. This amplifies the gene pool, thereby, increasing the chances of acquiring genes essential to biological fitness and survival.