Although a great deal is known about the structure and molecular pathology of the human haemoglobin genes it is still not clear how their differential expression during normal development is regulated. As well as being of considerable interest to developmental geneticists, this problem has important practical implications. Variability in the expression of the foetal globin genes plays a major role in modifying the clinical course of some of the common genetic disorders of adult haemoglobin production. If it were possible to prevent the switching off of foetal haemoglobin production after the neonatal period, or to reactivate it even partially, we would have an extremely valuable approach to the management of these conditions, which are globally the commonest single gene disorders.
Here I shall summarize what has been learnt from the experimental systems that are being used to study the regulation of the developmental changes in globin gene expression. It will...
