Which electrophoretic pattern is indicative of sickle cell trait?

In sickle cell trait, the hemoglobin electrophoresis pattern typically shows a substantial presence of both hemoglobin A and hemoglobin S. The correct pattern indicates that individuals with sickle cell trait carry one normal allele and one mutated allele, leading to approximately 60% hemoglobin A and about 40% hemoglobin S in their profile.

This specific distribution reflects the genetic composition of someone with the sickle cell trait, where hemoglobin S does not dominate but is still significant enough to be detected, resulting in an approximate ratio of hemoglobin types as observed.

The presence of hemoglobin A2 is minor in comparison and does not significantly deviate in representation, hence it makes sense that in the correct answer, hemoglobin A2 is present in small amounts.

Other options show different proportions that do not align with the expected pattern for sickle cell trait, such as having either a predominant percentage of hemoglobin S or an absence of hemoglobin A, which would typically characterize other conditions such as sickle cell disease or thalassemia.