Some Consequences of Nuclear-Cytoplasmic Recombinations among Various Neurosporas

Abstract

The rationale underlying the experiments to be reported is essentially simple. The existence of cytoplasmic genetic systems of biological significance leads to the presumption that such systems participate in evolution. As a facet of the speciation process, one might expect, therefore, the occurrence of cytoplasmic divergence, engendered by the same sorts of circumstances and processes that lead to nuclear divergence, and possibly, of course, as a consequence of nuclear divergence. As a corollary, in given instances coordinated nuclear and cytoplasmic divergence is to be expected, since natural selection should favor nuclear-cytoplasmic systems that work in harmony. The work of Michaelis (1954) with members of the genus Epilobium has led him to just such conclusions. Other reports of plasmon differences, particularly in higher plants, seem to have similar implications. A review by Caspari (1948) encompasses much of the pertinent literature.