Figure 1. “Russian doll” model [10].

When population genetic tests are performed with appropriate markers (of sufficient resolution) within each of the near-clades, a and b, that subdivide the species, A, under study (large tree, left part of the figure), they reveal within these near-clades a miniature picture of the whole species, with the two main PCE features, namely linkage LD and lesser near-clades (two small trees, a′ and b′, right part of the figure). This shows that PCE obtains also within the near-clades, and that these do not correspond to cryptic, potentially panmictic, biological species.