Final answer:
Copy number variations (CNVs) affect human phenotypes by altering the amount of DNA. These variations can influence gene expression and protein production, leading to different health outcomes and phenotypic diversity. CNVs can also impact natural selection and evolutionary processes.
Step-by-step explanation:
Copy number variation (CNV) plays a significant role in shaping human phenotypes by changing the amount of DNA present in the genome. This can happen through deletion, where DNA is missing, insertion, where additional DNA is added, or duplication, where copies of a segment of DNA are repeated. These changes can result in a variety of genetic conditions and affect how individuals respond to drugs, as different amounts of DNA can influence gene expression and, subsequently, protein production. When CNV occurs in genes involved in disease mechanisms or drug metabolism, it can have a large impact on individuals’ health outcomes, making it a focus of medical research.
Moreover, as genetic variations, including CNVs, are inherited, they contribute to the diversity of phenotypes seen in a population. These phenotypic variations provide a substrate for natural selection, shaping the genetic makeup of future generations. CNVs have been found to affect around 12 percent of the human genome, indicating that structural variation is a significant source of human genetic diversity and an important factor to consider in both evolutionary biology and medical genetics.