Pleiotropy is evident when:
A= More than one of the below
B = The environment effects the phenotype
C = Males are hemizygous (i.e., sex-linked) for a gene
D = One trait is influenced by many genes
E = A single gene has multiple effects on the phenotype
EXPLAIN YOUR ANSWER
The correct answer and explanation is :
The correct answer is E: A single gene has multiple effects on the phenotype.
Explanation:
Pleiotropy occurs when a single gene influences multiple, seemingly unrelated traits. In other words, one gene can affect more than one aspect of an organism’s phenotype (the observable physical or biochemical characteristics). This phenomenon is crucial in understanding how genes contribute to complex traits and diseases, as well as in evolutionary biology, where pleiotropy can have significant implications for the adaptive processes of organisms.
In the context of the options:
- A: More than one of the below – This choice is not specific and doesn’t directly describe pleiotropy.
- B: The environment affects the phenotype – While the environment can indeed influence the phenotype (a concept called “phenotypic plasticity”), this is not related to pleiotropy. Pleiotropy specifically refers to the effects of a single gene on multiple traits, not environmental influences.
- C: Males are hemizygous (i.e., sex-linked) for a gene – This statement refers to the genetic condition in males for sex-linked genes, especially X-linked genes. Hemizygosity affects how traits are expressed in males but is not directly related to pleiotropy. Pleiotropy concerns one gene affecting multiple traits, regardless of sex-linked inheritance.
- D: One trait is influenced by many genes – This describes polygenic inheritance, not pleiotropy. Polygenic inheritance refers to a situation where multiple genes contribute to a single trait, such as height or skin color, whereas pleiotropy involves a single gene affecting multiple traits.
- E: A single gene has multiple effects on the phenotype – This is the definition of pleiotropy. For example, a mutation in a single gene could lead to multiple effects, such as in the case of Marfan syndrome, where mutations in the fibrillin-1 gene cause effects on the skeleton, cardiovascular system, and eyes.
In summary, pleiotropy is a concept where one gene exerts multiple effects on different traits, making option E the correct answer.