Gene Recombination in Chlamydomonas reinhardi

Abstract

One arbitrary distinction between groups of organisms is based on the presence or absence of a clearly defined nucleus. Such a distinction places the blue-green algae, bacteria and viruses in one category, the protocaryotes, and all other organisms in another, the eucaryotes. This distinction may be meaningful when one considers the phenomenon of gene recombination in the two groups. Studies of gene recombination among protocaryotes, bacteriophages and bacteria, have yielded results which cannot be ascribed to the classical scheme of crossing over since the recombinational event does not necessarily occur at a “four-strand” stage, recombination products are not always reciprocal, and interference is often “negative”. Indeed, such departures from the classical scheme suggest that the mechanism for gene recombination is not one of crossing over but rather some form of recombination which occurs during the process of the replication of genetic material. Such a process was envisaged for...