allele vs allele

Source:  allele vs allele    Tag:  dominant allele
dominant allele - an allele that produces the same phenotype whether its paired allele is identical or different
recessive allele - an allele that produces its characteristic phenotype only when its paired allele is identical
Imagine that two alleles will always be present in forming a phenotype. Some are dominant and some are recessive.Recessive alleles will not show up if there is a single dominant allele present. Dominant alleles take priority over recessive alleles so if there is a single dominant allele present it will always effect the phenotype. 

For example: 


B - dominant 

b - recessive 

bb = recessive shows through 

BB = dominant shows through 
Bb = dominant shows through 
bB = dominant shows through