pleiotrópia

Pleiotropy refers to a phenomenon in genetics where a single gene influences multiple, seemingly unrelated phenotypic traits. Instead of a gene controlling just one characteristic, its expression affects several different aspects of an organism's development or function. This contrasts with the more straightforward concept of a gene having a single Mendelian effect.

The mechanisms behind pleiotropy can be diverse. A gene might code for a protein that plays a role in multiple cell types or signaling pathways. Alternatively, the gene product might be involved in a fundamental biological process that is essential for the development of various organs or systems. Mutations in such genes can therefore have widespread consequences, leading to a cascade of observable effects.

Examples of pleiotropy are found across the biological spectrum. In humans, the gene responsible for phenylketonuria (PKU), an inborn error of metabolism, causes a range of symptoms including intellectual disability, fair skin, and eczema, all stemming from a single defective enzyme. Similarly, in plants, a gene affecting flower color might also influence seed size or plant height. Understanding pleiotropy is crucial for comprehending complex genetic interactions and the inheritance of traits. It highlights that genetic control is often more intricate than a simple one-gene-one-trait relationship.