How do mutations happen, and how do they influence the future of a species? Molecules of sickle-cell hemoglobin stick to one another, forming rigid rods. These rods cause a person's red blood ...

In other words, mutations occur randomly with respect to whether their effects are useful. Thus, beneficial DNA changes do not happen more often simply because an organism could benefit from them.

Mutations occur continuously and can be spontaneous ... However, most DNA mutations do not alter a protein. One reason is because several different triplets can code for the same amino acid.

"Two of these mutations occur normally in B cells, but the presence of chronic viral particles that can't be cleared creates ongoing stimulation. The third mutation, linked to the development of ...