Why do the vectors need to have a selective antibiotic resistance?

Vectors need to have selective antibiotic resistance to facilitate the identification and selection of successfully transformed cells. When a vector carrying an antibiotic resistance gene is introduced into host cells, only those that have taken up the vector will survive in the presence of the antibiotic. This selective pressure allows researchers to efficiently isolate and propagate cells that have incorporated the desired genetic material, ensuring that the experiments focus on the successful transformants.