A boy inherits an allele for pointed nose from his father and an allele for rounded nose form his mother. During fertilisation, the two alleles are paired up alongside of each other at the same loci when the chromosomes from each parent come together. Now the two alleles are in competition' with one another the winning allele will be able to influence the nose shape ore than the losing one. Geneticists use two scientific terms to describe both the winner and loser in this case: dominant and recessive.