Final answer:
Homologous chromosomes are chromosome pairs with genes at identical locations but may contain different alleles. Homologs undergo recombination during meiosis, leading to genetic diversity in gametes. Homozygosity and heterozygosity result from inheriting identical or different alleles, respectively, for a given gene.
Step-by-step explanation:
Homologous chromosomes, often referred to simply as homologs, are pairs of chromosomes in a diploid organism that have the same morphology with genes located at the exact same positions, or loci. Every individual receives one chromosome of each pair from each parent, thus having pairs of homologous chromosomes. These chromosomes are the same length and have the same gene sequence order, but they may contain different versions of the same genes, known as alleles.
Alleles are alternate forms of genes responsible for the variations in traits that organisms display. When organisms have two identical alleles for a specific gene, they are said to be homozygous for that trait, whereas different alleles for the same gene result in heterozygosity. This genetic variation is the basis for diverse characteristics within a species, as individuals inherit unique combinations of alleles from their parents.
During meiosis, specifically meiosis I, homologous chromosomes undergo recombination, where segments of genetic material, and therefore alleles, are shuffled between the maternal and paternal homologs. Recombination ensures genetic diversity in the gametes produced. Hence, gametes contain only one set of chromosomes—23 individual chromosomes in humans—instead of a pair. The outcome of mitosis, however, is the creation of two daughter cells, each with an identical set of paired chromosomes.