Final answer:
Using only one trait would limit understanding of genetic diversity, as sickle-cell trait and lactose tolerance reflect different historical, environmental, and evolutionary influences. Analyzing both traits provides a more comprehensive view of the population's genetic landscape.
Step-by-step explanation:
If you had data about only one trait, either the sickle-cell trait or lactose tolerance, your answer regarding human variation at the bus station might differ significantly. Limiting data to one of these traits would offer a narrow glimpse into the population's genetic diversity, as each trait reflects different genetic, environmental, and evolutionary influences.
Population genetics seeks to understand such variations in allele frequencies within a population. The existence of the sickle-cell trait at higher frequencies in certain populations suggests a historical advantage against malaria, a factor not necessarily at play with lactose tolerance, which relates to dietary habits and domestication of dairy animals. The analysis of only one trait would provide incomplete information on the broader genetic landscape of the population.
For example, the sickle-cell trait is a classic case of balanced polymorphism, where the heterozygous condition provides some protection against malaria, while homozygous individuals suffer from sickle-cell disease. On the other hand, lactose tolerance into adulthood is a result of a genetic mutation that allows the production of lactase enzyme, reflecting a cultural adaptation rather than a response to a parasitic disease.
Therefore, considering only one trait could lead to an oversimplified or skewed understanding of genetic variation and adaptations within the population.