Mitochondrial DNA: an advance in eukaryotic cell biology in the 1960s

Between 1950 and 1960 mitochondria were recognized as well-characterized organelles of animal and fungal cells. They shared more functional autonomy than other cellular structures. The transmission of some mitochondrial characteristics did not obey Mendelian rules and followed cytoplasmic inheritance patterns. Was this situation a consequence of still unknown complexities? We present a personal account on how approaches were set up to test very different hypotheses. In the end, it was shown that mitochondria had their own DNA, mitochondrial DNA, and that this molecule carried information specific to these organelles.