Final answer:
Scientists compare known variants to new variants to identify genetic variants that are more common in people with a disease compared to those without the disease. This helps understand the genetic basis of diseases and develop strategies for prevention and treatment.
Step-by-step explanation:
When the known variants are compared to new variants, scientists are able to identify genetic variants that are more common in people with a specific disease compared to those without the disease. By analyzing the genetic makeup of a large number of individuals, scientists can determine if certain variants increase the risk of a disease. This information helps researchers understand the genetic basis of diseases and develop strategies for prevention and treatment.