When will a dominant trait show its effect in the presence of one dominant gene.
This goes to say that a dominant trait will show its effect even when individual only has one copy of the allele.
Answer:
In heterozygotic individuals, the gene for sickle cell anemia is protective against malaria.
Explanation:
Through the same mechanism that the mutation associated with sickle cell anemia produces the disease (altered hemoglobin structure), having a single copy of the mutation (that is, being heterozygotic) provides protection against malaria. This is believed to be due to the altered structure causing difficulty for the malaria parasite when it attempts to enter red blood cells as part of its life cycle.
Today, there are medications to successfully treat malaria, but it still killed 627,000 people in 2020. This represents a significant evolutionary pressure for genes that would prevent serious malarial illnesses. As malaria was and still is common in African regions, the result was a higher prevalence of sickle cell anemia in those of African descent.
Lamarck developed the theory of acquired characteristics that organisms changed during their lifetime to accommodate their environment and that these acquired characteristics became inherited in their offspring. This theory was preceded for example by Erasmus Darwin who believed that "improvements" to organisms could be passed on or inherited.