The elusive clone - In search of its true nature and identity

Abstract

Sex in eukaryotes involves a combination of meiosis and syngamy; absence of these processes leads to asexual reproduction of which there are different kinds (Box 9.1). Lineages comprising subsequent generations of such asexually reproducing individuals are nearly invariably referred to as clones. In addition, they are mostly identified by genetic techniques using different molecular markers and with differing powers of resolution. Here, we demonstrate that various clonal concepts are being used without clear discrimination, which can significantly impede both the repeatability of, and comparisons between, studies. An example of the resulting dilemma is that, according to one concept, the more than 350 species of obligate asexual bdelloid rotifers all belong to one clone, whereas according to another concept, each of these species comprises several clones.