a set of standards governing inheritance of traits first described by Gregor Mendel (1822–1884): (a) hereditary differences result from genes; genes are present in pairs, each of which is called an allele; (b) one allele may dominate the other; (c) during reproduction, paired alleles separate, allowing segregation of alleles; (d) resulting offspring exhibit segregation ratios for various character combinations according to laws of probability, because each segregating allele is distributed randomly to one gamete and independently of other genes (provided the genes are not linked), and because eggs and sperm unite randomly —see epigenetic, linkage, meiosis, qualitative inheritance, simple Mendelian inheritanceThis definition last updated 07/17/2008