Postnatal appearance of a short DNA repeat length in neurons of the cerebral cortex

A short DNA repeat length of 162 base pairs was present in neurons of the adult rabbit cerebral cortex while a 198 base pair repeat was found in cortical glial and kidney cells. The short DNA repeat length in cortical neurons was not evident in fetal or new born brain but it appeared during early postnatal development between 2 $\text{1}\text{2}$ and 3 $\text{1}\text{2}$ days in rabbit and between 4 and 7 days in mouse.