* Dominance is about expression, not value: Dominant alleles are simply those that express their trait even when only one copy is present. Recessive alleles only express their trait when two copies are present. This doesn't mean one is inherently superior.
* Environment matters: What's advantageous for an organism depends on its environment. A dominant allele might be beneficial in one environment, but detrimental in another.
* Genetic diversity is key: Having both dominant and recessive alleles within a population helps ensure genetic diversity. This diversity is crucial for a species' survival and adaptation to changing environments.
* Examples:
* Sickle cell anemia: The sickle cell allele is recessive, but in areas with malaria, it provides a survival advantage by making red blood cells less susceptible to the parasite.
* Cystic fibrosis: The cystic fibrosis allele is recessive, but it can provide some resistance to certain bacterial infections.
Think of it this way: Dominant and recessive are just labels for how a gene is expressed. The "better" allele depends on the specific trait and the environment.
