A disease called phenylketonuria causes mental problems, reduces skin pigmentation, and also affects the coloration of urine. What kind of effect is exhibited by the gene responsible for this disease?

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  • Answer:



    Pleiotropy is a genetic condition in which a single gene conditions the expression of multiple phenotype. There are different types of pleiotropy depending on the underlining mechanism

    • gene pleiotropy
    • developmental pleiotropy
    • selectional pleiotropy
    • antagonistic pleiotropy

    Phenylketonuria is a disease characterized by increased level of amino acid phenylalanine in the blood. It caused by mutation to the gene responsible for breaking down phenylalanine in the blood. Elevated level of phenylalanine causes other issues such as mental problems, urine coloration and reduction in skin pigmentation. This is a clear case of pleiotropy.