Ultrastructural analysis of haemopoiesis in W/Wv anaemic mice.

This study is an ultrastructural analysis of haemopoiesis in W/Wv anaemic mice in whom the anaemia is caused by a defect in the haemopoietic stem cell. Cellularity of marrow is normal but there is an increase in the proportion of less mature cells suggesting a delay in maturation. In addition, heterochromatin constitutes a higher proportion than normal of the nucleus in most stages of maturation suggesting a defect in DNA activation. The findings suggest that in this strain not only the differentiation of the haemopoietic stem cell but also the maturation of the committed cell is defective.