Mal was zu Nattern (Egytische und Europäische) Taxonomie...

Diskussionen zur Systematik und Taxonomie von Reptilien, Amphibien und Wirbellosen

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Mal was zu Nattern (Egytische und Europäische) Taxonomie...

Beitrag von domino » Mi Mär 07, 2012 9:30

Zwei neue Arbeiten über Nattern

Sayed, Nadia H. M. 2012. Genetic Diversity among Eight Egyptian Snakes (Squamata-Serpents: Colubridae) Using RAPD-PCR. Life Science Journal 9(1). ... 23_430.pdf
Genetic variations between 8 Egyptian snake species, Psammophis sibilans sibilans, Psammophis sudanensis, Psammophis schokari schokari, Psammophis schokari aegyptiacus, Spalerosophis diadema, Lytorhynchus diadema, Coluber rhodorhachis, Coluber nummifer were conducted using RAPD-PCR. Animals were captured from several locality of Egypt (Abu Rawash-Giza, Sinai and Faiyum). Obtained results revealed a total of 59 bands which were amplified by the five primers OPB-01, OPB-13, OPB-14, OPB-20 and OPE-05 with an average 11.8 bands per primer at molecular weights ranged from 3000-250 bp. The polymorphic loci between both species were 54 with percentage 91.5 %. The mean band frequency was 47% ranging from 39% to 62% per primer .The similarity matrix value between the 8 Snakes species was ranged from 0.35 (35%) to 0.71 (71%) with an average of 60%. The genetic distance between the 8 colubrid species was ranged from 0.29 (29%) to 0.65 (65%) with an average of 40 %. Dendrogram showed that, the 8 snake species are separated from each other into two clusters .The first cluster contain 4 species of the genus Psammophis. The second cluster includes the 4 species of the genera, Spalerosophis; Coluber and vLytorhynchus[/i]. Psammophis sibilans is sister to Psammophis sudanensis with high genetic similarity (71%) and Psammophis schokari schokari is sister to Psammophis schokari aegyptiacus with high genetic similarity (70%). The Coluber rhodorhachis are clustered and closer to Spalerosophis diadema (70%) than to Coluber nummifer (57%). Therefore, the evolutionary history of snakes still remains controversial. It is concluded that, the similarity coefficient and the genetic distance value between the 8 snake species indicates that, the 8 snake species are not identical and separated from each other.

Fritz, Uwe, Claudia Corti & Martin Päckert. 2012. Mitochondrial DNA sequences suggest unexpected phylogenetic position of Corso-Sardinian grass snakes (Natrix cetti) and do not support their species status, with notes on phylogeography and subspecies delineation of grass snakes. Org Divers Evol DOI 10.1007/s13127-011-0069-8
We supplement a previously published mitochondrial DNA data set of grass snake sequences (ND1, ND2, ND4, cyt b, in total 3,806 bp) with sequences of Corso-Sardinian and Tuscan specimens and infer their phylogeny using Bayesian, maximum likelihood and maximum parsimony methods. In addition, we estimate divergence times of grass snake clades using a relaxed molecular clock calibrated with fossil evidence, and, in a second approach, the post-Messinian reopening of the Strait of Gibraltar. Recently it was suggested that Corso-Sardinian grass snakes represent a distinct species: Natrix cetti. All tree-building methods
revealed well-supported branching patterns and deep divergences among grass snakes. However, sequences of N. natrix were consistently paraphyletic with respect to Corso-Sardinian sequences. The sister group of Corso-Sardinian grass snakes is a clade embracing N. n. helvetica and N. n. lanzai. Extensive gene flow between N. n. helvetica and a more distantly related subspecies (N. n. natrix) is well known, which is why we conclude that the status of Corso-Sardinian grass snakes as subspecies of N. natrix should be reinstated. Many currently recognized grass snake subspecies conflict with mitochondrial clades, suggestive of inappropriate morphological taxon delineation and mitochondrial introgression. Divergences among grass snakes are old, and the results of the two independent dating approaches are largely congruent. Accordingly, the Alpine orogenesis seems to have caused the origin of the oldest clade, corresponding to Iberian N. n. astreptophora. The formation of Corso-Sardinian grass snakes was dated to the Early Pliocene and could result from post-Messinian flooding of the Mediterranean Basin. Another deeply divergent clade of approximately the same age, endemic in central and northern Europe, suggests the Pleistocene survival of grass snakes north of the Alps. At least one glacial refuge in which old lineages survived Pleistocene cold periods was located on each of the three major southern European peninsulas and in Anatolia. Due to pronounced sequence divergences among Italian and southern Swiss grass snakes, we hypothesize multiple refugia south of the Alps and in the Apennine Peninsula, and there is evidence for two refuges
on the Balkan Peninsula.

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Beitrag von Conus » Mi Mär 07, 2012 11:03

Das erste paper ist aber recht... naja.
Sieht für mich nach den krampfhaft publizierten Ergebnissen einer nicht durchdachten Diplomarbeit aus. Einfach acht wahllos herausgepickte Arten zu nehemn ist nicht allzu glücklich. Und RAPD? Wer bitte benutzt noch diese Steinzeitmethode???

Das zweite kommt doch schon in einem anderen Gewand daher. :-)
Anmerkung von Forenteam:
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