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Merenschwand, Switzerland

Ducrest A.-L.,University of Lausanne | Ursenbacher S.,University of Basel | Golay P.,University of Lausanne | Mebert K.,Siebeneichenstrasse 31 | And 2 more authors.
Biological Journal of the Linnean Society | Year: 2014

Colour polymorphism is widespread among vertebrates and plays important roles in prey-predator interactions, thermoregulation, social competition, and sexual selection. However, the genetic mechanisms involved in colour variation have been studied mainly in domestic mammals and birds, whereas information on wild animals remains scarce. Interestingly, the pro-opiomelanocortin gene (POMC) gives rise to melanocortin hormones that trigger melanogenesis (by binding the melanocortin-1-receptor; Mc1r) and other physiological and behavioural functions (by binding the melanocortin receptors Mc1-5rs). Owing to its pleiotropic effect, the POMC gene could therefore account for the numerous covariations between pigmentation and other phenotypic traits. We screened the POMC and Mc1r genes in 107 wild asp vipers (Vipera aspis) that can exhibit four discrete colour morphs (two unpatterned morphs: concolor or melanistic; two patterned morphs: blotched or lined) in a single population. Our study revealed a correlation between a single nucleotide polymorphism situated within the 3'-untranslated region of the POMC gene and colour variation, whereas Mc1r was not found to be polymorphic. To the best of our knowledge, we disclose for the first time a relationship between a mutation at the POMC gene and coloration in a wild animal, as well as a correlation between a genetic marker and coloration in a snake species. Interestingly, similar mutations within the POMC 3'-untranslated region are linked to human obesity and alcohol and drug dependence. Combined with our results, this suggests that the 3'-untranslated region of the POMC gene may play a role in its regulation in distant vertebrates. © 2013 The Linnean Society of London.


Castella B.,University of Lausanne | Golay J.,University of Lausanne | Golay P.,University of Lausanne | Mebert K.,Siebeneichenstrasse 31 | Dubey S.,University of Lausanne
Journal of Zoology | Year: 2013

Alternative morphotypes can confer important selective advantages in different habitats, whereas they can be penalized in other circumstances. In ectotherms, such as reptiles, the body colour can have direct effects on numerous aspects of their existence, such as thermoregulation or prey-predator interactions. Darker melanic individuals show lower skin reflectance and consequently heat up more rapidly and maintain optimal body temperatures more easily than lighter coloured individuals. As a consequence, melanistic individuals of diurnal species in cool areas may exhibit higher body condition, growth rate, survival and fecundity than lighter coloured individuals. Such advantages of dark coloration may be counterbalanced by a lower crypsis to predators and a decreased foraging efficiency. We investigated, in two montane populations of asp vipers Vipera aspis, the relationship between (1) colour polymorphism and body condition and length and (2) the coloration of individuals and their elevational distribution. We showed significant relationships between (1) the coloration, body condition and sex of individuals; (2) sexes and reproductive state and morph frequency; and (3) colour morphs that were distributed following an elevational gradient. Hence, colour polymorphism plays an important role in the ecology and evolution of the asp viper and is maintained through differential selective pressures. © 2013 The Zoological Society of London.


Mebert K.,Siebeneichenstrasse 31 | Masroor R.,Pakistan Museum of Natural History | Chaudhry M.J.I.,WWF Pakistan
Pakistan Journal of Zoology | Year: 2013

Based on the recent rediscovery of a dice snake (Natrix tessellata) in the Karakoram mountains of north-central Pakistan (western Karakoram) and the only other records from northwestern Pakistan we utilize contemporaneous information on the ecology of N. tessellata and climate fluctuations during the Holocene to analyze its limited distribution to a few mountain valleys. We elaborate several plausible expansion routes from a glacial refugium in northern Afghanistan through the Hindu Kush Mountain Range into Pakistan and the western Karakoram. The apparent range restriction of N. tessellata to the mountains of northern Pakistan is discussed in regards to postglacial expansion speed and routes, available period during the Holocene, habitat requirement, competition with another semi-aquatic water snake, Xenochrophis piscator, and potential misidentification with the latter species. Copyright 2013 Zoological Society of Pakistan.


Dezfoulian R.,University of Tehran | Mebert K.,Siebeneichenstrasse 31 | Karami M.,University of Tehran | Kaboli M.,University of Tehran | Ahmadzadeh F.,Shahid Beheshti University
Journal of Natural History | Year: 2012

The distribution of the Caucasian agama (Laudakia caucasia) has been studied related to structural parameters during spring and summer 2010 in an area of 9186 ha in the Sorkh-e-Hesar National Park, Tehran province, Iran. The habitat parameters included structure properties of plant coverage, plant richness, proportional surface coverage of rock and bare soil, distance to the nearest shelter and topography (slope, cardinal direction and altitude). In total, 92 plots were sampled and habitat suitability was analysed using binary logistic regression. Results showed that, ordered by significance, rocky coverage, bare soil and plant coverage are the most efficient factors explaining the presence of the agama species in the study area. The relationship of each significant habitat parameter is briefly discussed in the context of the lizard's biology, and its need for thermally and structurally suitable microhabitats. © 2012 Copyright Taylor and Francis Group, LLC.


Ahmadzadeh F.,Shahid Beheshti University | Carretero M.A.,University of Porto | Mebert K.,Siebeneichenstrasse 31 | Faghiri A.,Islamic Azad University at Damghan | And 3 more authors.
Acta Herpetologica | Year: 2011

Natrix natrix is, together with N. tessellata, the only representative of water snakes found in Iran. The lack of ecological studies on this species in Iran stimulated the current preliminary research on some basic biological traits. From April to July 2008, a total of fifty five snakes were collected from two stations in the southern part of the Caspian Sea coast, Iran: Gomishan Wetland and Sari. Basic morphometrics were compared between sexes and stations and gonadal development was compared between stations and seasons. At the two stations, adult sex ratio was not different from 1:1 and juveniles composed a predominant portion of the sample. Both sexes had unimodal length class size with a peak at 40-45 cm snout-vent length (SVL). Body sizes were unusually small for the species and no SVL sexual dimorphism was detected although males were relatively heavier than females for the same SVL. Snakes of both sexes attained larger size with better body condition at Sari than in Gomishan. Males and females carried more mature gonads in summer. However, in Sari males developed relatively larger testes earlier in the season and both sexes displayed less synchronic reproduction at this station. These results are best explained by local variations in habitat, trophic availability and degree of environmental disturbance. © Firenze University Press.

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