| by admin | No comments


Abstract. The aim of this paper is to describe morphological characteristics of fresh- water triclads in Herzegovina and to provide a key for their. 1 Introduction. The polyclads are the most primitive free living flatworms of the phylum Platyhelminthes. These worms are dorso-ventrally. -Eight new species belonging to the genus Cycloporus (Platyhelminthes. Polycladida,. Euryleptidae) are described from Australasian waters including eastern.

Author: Fekora Mikajar
Country: Trinidad & Tobago
Language: English (Spanish)
Genre: Sex
Published (Last): 11 April 2015
Pages: 202
PDF File Size: 10.35 Mb
ePub File Size: 2.99 Mb
ISBN: 414-9-92142-548-9
Downloads: 31143
Price: Free* [*Free Regsitration Required]
Uploader: Doura

Dugesia sicula (Platyhelminthes, Tricladida): the colonizing success of an asexual Planarian

Origin and expansion A recent study [ 8 ] emphasised that D. Morphological, karyological and biochemical data in free-living and symbiotic Platyhelminthes; pp.

In a functional protein coding sequence, more changes are expected in the 1st and 3rd codon positions. Gustav Fischer Verlag; Supplementary Material Additional file 1: On Dugesia gonocephala from Western Europe. Fissiparous reproduction can have effects on the distribution of genetic variability within the populations and even on individuals that could perhaps help disentangle this situation. In this area, D. Descrizione di Dugesia siculanuova sp. Freshwater planarians do not exhibit larval dispersal stages or forms resistant to desiccation; these individuals thus require contiguous freshwater bodies to survive and disperse [ 1617 ].

Leria personal communication and one of platyhel,inthes authors, MRallows us to confidently state that D. The species most probably originated in Africa and dispersed through the central Mediterranean.

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. This could be considered a special case of heteroplasmy that differs from pplatyhelminthes in which heteroplasmy is transmitted sexually or parthenogenetically through the mitochondria present in the oocyte and the spermatozoon in some cases where all cells from a new individual will present the same haplotypes.

Schematic representation of the spreading of a new mutation in fissiparous organisms. In the northwestern populations northern Catalonia and Franceall 97 sequenced individuals showed haplotype B one individual was polymorphic but likely non-heteroplasmic. It mostly comprises fissiparous populations asexual reproduction by body division and regenerationmost likely sexually sterile, and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion.


Fundamentals of planarian regeneration. Haplotype C is observed in non-heteroplasmic jurnsl in Morocco and the southern Iberian Peninsula and may have spread from there to the Canary Islands, where C was the only haplotype observed.

Phylum Platyhelminthes

Int J Dev Biol. Nucl Acids Symp Ser. Evidence platyhelminthea recent human-mediated range expansion? Proc Natl Acad Sci. All of the individuals with polymorphic sites exhibited significant differences between the two values except for the s However, the morphological characters of the copulatory apparatus of the sexual specimens allowed the species to be described.

However, we can speculate that the presence of haplotype C in heteroplasmic individuals in the central regions could indicate its origin is there, and its prevalence in the s01, s02 and s05 populations could be the result of a founder effect during colonisation.

This result suggests that, in these individuals, despite that some point mutations could be caused by polymerase jurnap, there are most likely low-frequency haplotypes that we cannot detect in the direct sequences using PCR. Leria —Mallorca— and E. Don’t have an account? The competition between D.

However, the question as to how this species attained such a wide platyhelminthees with such a low dispersal capability [ 1617 ] remains. A karyological study on populations of Dugesia gonocephala s. The catenulids are characterised by their single, biciliate protonephridia. Evidence for the evolution of bdelloid rotifers without sexual reproduction or ppatyhelminthes exchange.

Rozas for his advice on the analytical methodologies.

The literature suggests that D. Mitochondrial pseudogenes are pervasive and often insidious in the snapping shrimp genus Alpheus. Conclusions The distribution and frequency of the most frequent haplotypes and the presence of heteroplasmic individuals allow us to gain an understanding of the recent history of the species, together with previous knowledge on its phylogenetic relationships and age: Under the hypothesis that D. Additionally, in the Greek population from Rhodes s56D.


Polymerase mistake versus heteroplasmy test. Civil War American History: Tricladida Ital J Zool.

Microturbellarians (Platyhelminthes and Acoelomorpha) in Brazil: invisible organisms?

The most recent report [ 57 ] indicates that the invasion of G. NUMTs in sequenced eukaryotic genomes. Moreover, it is expected platyhelminthss the distribution of substitutions for a functional sequence shows a bias with more differences observed at the third and first position than at the second.

Haplotype B was present in individuals from 18 populations, the majority of which were found northwest of the Mediterranean. However, several populations of D.

Table 5 Pltyhelminthes of diversity parameters between different triclad species. Heteroplasmy has been detected in many species [ 23 ], and some studies in humans have shown it increases with age in somatic cells and is more frequent in certain tissues, such as muscle tissue, most likely because of increases in the number of mutations caused by the presence of oxidative radicals [ 2324 ]. In both cases, the hypotheses contrast with the poor dispersion capability assumed for freshwater planarians [ 1617 ].

Fissiparous planarians do not develop a copulatory apparatus, which precludes the assignment of these populations to any species since this structure provides most of the defining characters for species description in planarians. Table S2exhibited at least one of the most frequent haplotypes A or Band all of the individuals showed at least one unique haplotype Additional file 1: