<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2018) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2018) (Learn how and when to remove this template message) </Td> </Tr> <P> Dominance in genetics is a relationship between alleles of one gene, in which the effect on phenotype of one allele masks the contribution of a second allele at the same locus . The first allele is dominant and the second allele is recessive . For genes on an autosome (any chromosome other than a sex chromosome), the alleles and their associated traits are autosomal dominant or autosomal recessive . Dominance is a key concept in Mendelian inheritance and classical genetics . Often the dominant allele codes for a functional protein whereas the recessive allele does not . </P> <P> A classic example of dominance is the inheritance of seed shape in peas . Peas may be round, associated with allele R, or wrinkled, associated with allele r . In this case, three combinations of alleles (genotypes) are possible: RR, Rr, and rr . The RR individuals have round peas and the rr individuals have wrinkled peas . In Rr individuals the R allele masks the presence of the r allele, so these individuals also have round peas . Thus, allele R is dominant to allele r, and allele r is recessive to allele R . This use of upper case letters for dominant alleles and lower case ones for recessive alleles is a widely followed convention . </P>

What are the type of genes that prevent other genes from showing their phenotype