Intra-species differentiation within Paramecium aurelia spp. complex and
Paramecium jenningsi (CILIOPHORA, PROTOZOA)

Ewa Przybos
Institute of Systematics and Evolution of Animals, Polish Academy of
Sciences, Krakow

Paramecium aurelia spp. complex and P. jenningsi are valid morphospecies.
P. aurelia is composed of 15 biological species regarded as inbreeders,
among them P. triaurelia, P. pentaurelia, P. sixaurelia, and P.
novaurelia, differing in degree characteristic for them inbreeding, were
chosen for studies.
P. jenningsi was regarded as composed of only one genetic species
(syngen) and their strains were known mainly from tropical regions, only
recently (1999 and 2000) new strains were collected also from places
situated beside it (China and Japan). P. jenningsi is characterized by
moderate outbreeding.
In the studies concerning the intra-species differentiation in both
morphospecies a combination of classical genetic methods (inter and
intra-strain crosses, in which F1 was obtained by conjugation and F2 by
autogamy) and RAPD-PCR fingerprints analyses (performed using the
oligonucleotide 10mer random primer Ro 460-04, Roth, Karsruhe, Germany,
characterized by the sequence 5'-GCAGAGAAGG-3') were used.
The existence of intra-species differenatiation, stronger in inbreeders
(the P. aurelia spp. complex) and weaker in moderate outbreeders (P.
jenningsi) was revealed.
  The species of the P. aurelia complex can be arranged in some order as
far as degree of inbreeding is concerned, from extreme inbreeders - P.
sexaurelia (some genetic isolation of genotype groups), by moderate
inbreeders - Paramecium novaurelia and P. triaurelia, to weak inbreeders -
P. pentaurelia (gene flow between groups of genotypes exists).
As concerns P. jenningsi, it was found that there exist different syngens
within it, genetically and genotypically separated. One comprising strains
from Florida, Uganda, India, Madagascar, Saudi Arabia and China and second
one comprising strains from Japan.