Percoll-Larex gradients of the five members of the pedigree. Lane B, density beads; lane 1, normal blood; lane 2, sickle cell anemia; lane 3, HSR (high HbS-Oman); lane 4, ISH (high HbS-Oman); lane 5 MSR (high HbS-Oman); lane 6 MSK (low HbS-Oman); lane 7 SSR (low HbS-Oman).