Gametes are created by an extraordinary sort of cell division known as meiosis. Meiosis contains two rounds of cell division without DNA replication in the middle. This process reduces the number of chromosomes by half.
Alleles are alternate forms of genes found on chromosomes. Homologous chromosomes have similar qualities, however they may have diverse alleles.
Haploid vs. Diploid
A cell with two sets of chromosomes is diploid, referred to as 2n, where n is the number of sets of chromosomes. Most of the cells in a human body are diploid. A cell with one set of chromosomes, such as a gamete, is haploid.
Meiosis is a process of cell division that reduces the chromosome number by half and produces sex cells, or gametes.
Meiosis is divided into two parts: Meiosis I and Meiosis II. Each part is like mitosis and can be isolated into similar stages: prophase, metaphase, anaphase, and telophase.
Crossing-over occurs only during prophase I.
Four genetically unique haploid cells result from meiosis.