PINK flowers. This is an example of Pseudo dominance.There are situations wherein only one recessive allele is inherited and yet is expressed. This is called pseudo dominance.The recessive trait is manifested as if it follows the pattern of inheritance of a dominant allele.Many X-linked genetic disorders in males are pseudo dominant.Since males receive one X chromosome and one Y chromosome, the recessive gene in the X chromosome leads to its expression.Hemophilia in males is an example of pseudo dominance.The gene responsible for the manifestation of hemophilia in males is recessive and X-linked.In genetics, the property of a gene or an allele to be expressed over the other gene in a pair is referred to as dominance. When a gene (allele) is expressed it is described as dominant.A gene that is not expressed is said to be recessive.In EPISTASIS, the interaction between genes is antagonistic, such that one gene MASKS or interferes with the expression of ANOTHER.“Epistasis” is a word composed of Greek roots that mean “standing upon”.The alleles that are being masked or silenced are said to be HYPOSTATIC to the epistatic alleles that are doing the masking.Often the biochemical basis of epistasis is a gene pathway in which the expression of one gene is dependent on the function of a gene that precedes or follows it in the pathway.An example of epistasis is pigmentation in mice.Co-dominance is a relationship between two versions of a gene.If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.In co-dominance, however, neither allele is recessive and the phenotypes of both alleles are expressed.