Final answer:
The single chain globin, also known as the beta chain of hemoglobin, has evolved through genetic changes over time. One important mutation in the beta chain leads to sickle cell anemia.
Step-by-step explanation:
The single chain globin, also known as the beta chain of hemoglobin, evolved over time. One important mutation in the beta chain leads to sickle cell anemia. In normal hemoglobin, the amino acid at position seven is glutamate, but in sickle cell hemoglobin, it is replaced by a valine.
It is fascinating to consider that a hemoglobin molecule consists of about 600 amino acids, and the structural difference between a normal hemoglobin and a sickle cell molecule is only a single amino acid out of the 600. This amino acid change is caused by a point mutation, which is a single base change in the gene.
Overall, the single chain globin evolved through genetic changes over time and continues to play a crucial role in the functioning of hemoglobin.