As for the research conducted by the four authors in the years immediately following
the publication of "Sickle Cell Anemia, a Molecular Disease", Itano, Singer and Wells
continued on the same vein by analyzing abnormal hemoglobin and its synthesis; whereas
Pauling returned to structural chemistry, particularly the structures of proteins.
Itano continued searching for abnormal hemoglobins in vivo and successfully found three other abnormal hemoglobins within the next five years.
He collaborated with James V. Neel for one of these discoveries. Wells and Itano returned
to the ratio issue and tried to determine the range of difference in the ratios of
sickle cell and normal hemoglobin in people with sickle cell trait. In addition, they
analyzed whether the personal differences depended on any of the following factors:
effect of time (i.e. Does an individual's ratio change over time or remain relatively
constant?), sex, age, environment, diet, and heredity. Of all the factors they tested,
Wells and Itano decided that only heredity might explain the range. In addition to
his work with Itano, Wells collaborated with two other researchers from the Caltech
chemistry department, Senior Research Fellow Walter A. Schroeder and Lois M. Kay to examine the amino acid sequences of sickle cell anemia and normal
hemoglobin. In the mid-1950s to the early 1960s, Itano and Singer investigated genetic
factors of diseases caused by abnormal hemoglobin by focusing on the synthesis of
polypeptide chains in normal and abnormal hemoglobin.
As a result of the powerful work conducted on sickle cell anemia, more people at Caltech
began to investigate normal and abnormal hemoglobins, but they were not alone in this
endeavor. The 1950s saw an extensive growth in laboratory studies of hemoglobin and
hemoglobinopathies. Additionally, genetic research boomed during this decade as a
result of work on deoxyribonucleic acid (DNA), especially after James Watson and Francis
Crick elucidated the structure of DNA in 1953.