Fragmentation of DNA in the retina of chicken embryos coincides with retinal ganglion cell death

Summary Neuronal cell death was studied in the developing retina of the chicken embryo. One of the most characteristic indices of the form of cell death termed apoptosis is regular, apparently internucleosomal fragmentation of DNA. When retinae of eight to seventeen day old chicken embryos were dissected out and the DNA from this tissue size fractionated on agarose gels, fragmentation typical of apoptosis was observed on day ten. The maximal amount of fragmentation was reached around day eleven and twelve and declined from day 15 to 17. These findings correlate in time with previous histological data on retinal cell death and demonstrate for the first time the occurrence of DNA fragmentation typical of apoptosis in the developing nervous system.