Peripheral blood morphology of homozygous ζ- and α1-null adult mice. (A) Blood from a mouse with wild-type globin genes on an outbred 129/Black Swiss genetic background demonstrating normal erythrocyte morphology. (B) Blood from a mouse with a ζ^−/− null genotype on an outbred 129/Black Swiss genetic background demonstrating abnormal red cell morphology. (C) Blood from a mouse with a α1^−/− null genotype on an outbred 129/Black Swiss genetic background demonstrating mildly abnormal red cell morphology. (D) Blood from a mouse with an α1^−/− null genotype on an inbred 129 genetic background displaying severe anisopoikilocytosis and highly abnormal red blood cell morphology. A more detailed description of the red cell morphology is given in the text.