Mitosis followed by cytokinesis results in two identical diploid cells. Genes are specific sequences of nucleotides, at a particular location on the chromosome, which carry information for inheritable traits. Alleles are slightly different molecular forms of a gene which specify different versions of the same trait. When homologous chromosomes are separated during meiosis, their paired genes are also separated, and end up in different gametes. Each pair of homologous chromosomes and the genes they carry are separated for distribution into one gamete independently of the other pairs of homologous chromosomes.
Allelic recombinations contribute to variations in phenotypes of offspring.
The phenotypic outcome from the activity of a single gene is pleiotrophy. Environmental factors may also induce variation in traits. An individual may be homozygous or heterozygous for a particular inheritable trait. Genotype refers to the particular genes an individual carries, and phenotype refers to an individual's observable traits. Monohybrid, dihybrid, and test crosses are important tools in the study of genetics.