A karyological analysis on six Italian populations the slow worm (Anguis veronensis Pollini, 1818) was performed and their genetic differentiation at the mitochondrial 16S rRNA gene fragment from a ...Spanish sample has been assessed. The Italian populations were karyologically uniform, all showing 2n=44 elements, of which 20 were macrochromosomes and 24 microchromosomes. Comparison with literature data on Central European populations showed a difference on the morphology of the 10(th) chromosome pair: submetacentric in Italian populations and telocentric in the Central European ones. Our analysis showed the presence of a fragile site on chromosomes of this pair, suggesting its propensity for structural rearrangements. Analysis of the 16S rRNA gene fragment showed uniformity among Italian populations (uncorrected genetic distance of 0.4%), and their genetic distinctness from the Spanish individual (uncorrected genetic distance of 4.2%). Our results confirm the existence of two different Anguis fragilis Linnaeus, 1758 lineages, each one characterized by a different cytotype.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The chromosomes of eight species of Rutilus and Scardinius, mostly endemic to the Italian and the Balkan peninsula, were analyzed by conventional and other banding techniques. Parallel analyses were ...conducted also on two leuciscine species, Alburnus albidus, for which we provide the first karyological analysis, and Leuciscus cephalus. All species examined displayed the same karyotype (2n = 50 chromosomes, 8 metacentric + 13 submetacentric + 4 subtelo/acrocentric pairs) with nucleolus organizer regions (NORs) on the ends of the shorter arms of a medium-sized submetacentric pair. In contrast, interspecific variation was observed in the distribution of constitutive heterochromatin. The variation observed in this genomic material proved to be systematically and phylogenetically informative. Indeed, a peritelomeric C-band on the first telocentric pair characterizes species of Rutilus and Scardinius. In both genera heterochromatin differentiation appears to be directed to a centromere-telomere direction, particularly evident along the metacentric elements of their karyotypes.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Karyotypes of three microhylid frog species of the Malagasy relict genus Scaphiophryne were studied: Scaphiophryne gottlebei, S. madagascariensis and S. spinosa. The latter two showed a plesiomorphic ...ranoid karyotype of 2n = 26. In contrast, tetraploidy was demonstrated in S. gottlebei, which constitutes an exceptional state among Malagasy amphibians. A combination of different banding techniques and of rDNA-FISH provided evidence for allopolyploidy in the species and for a completed subsequent functional and structural diploidization. Phylogenetic analysis of mitochondrial 16S rDNA sequences revealed a significant deceleration of nucleotide substitution rates in Scaphiophryne. The tetraploidy of S. gottlebei probably occurred early in their radiation. Ecological and behavioural patterns of Scaphiophryne probably favoured intraspecific gene flow and hybridization events, thereby leading to slow molecular substitution rates and to allopolyploid chromosome speciation in S. gottlebei.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The lizard Lacerta (Zootoca) vivipara has two modes of reproduction and is variable karyologically. We describe its karyological variation from literature data and from new data on two viviparous ...populations from France, on two oviparous populations from the Pyrénées in south-western France and on three oviparous populations recently discovered in Slovenia. Males have 36 chromosomes, whereas females have only 35 chromosomes in all viviparous populations and in the Pyrenean oviparous populations. This karyotype has been interpreted to result from a fusion of an ancestral sexual W chromosome with an autosome from the Z1 or from the Z2 pair. The karyotype formula is 32 autosomes +Z1Z2W for the female and 32 autosomes +Z1Z1Z2Z2 for the male. The karyotype of the Slovenian oviparous populations, 34 autosomes +ZZ in the male and 34 autosomes +ZW in the female, represents an evolutionary stage that preceded the chromosomal fusion. There is minor karyological variation, mainly concerning the W and Z2 chromosomes, within the Pyrenean oviparous populations. This parallels the geographic variation of the W-linked alleles of the MPI enzyme and suggests that allopatric differentiation of these oviparous populations might have occurred in the vicinity of the Pyrénées during the Pleistocene. The viviparous populations from western Europe carry a metacentric W chromosome, whereas oviparous populations from south-western Europe and eastern viviparous populations both show an acrocentric, or a subtelocentric, W chromosome. This suggests that the acrocentric-subtelocentric W is a primitive character and that viviparity probably arose in an eastern lineage of the species.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
We performed a phylogenetic analysis using nuclear (RAG‐1, RAG‐2) and mitochondrial (16S) markers, a statistical Bayesian reconstruction of ancestral distribution areas and a karyological analysis on ...most Malagasy species of the gekkonid genus Lygodactylus. The phylogenetic analysis largely confirms major basal branching pattern of previous molecular studies, but highlights significant differences concerning both the relationships between different species groups as well as those within groups. The biogeographic analysis supports a Malagasy origin of Lygodactylus, an oversea dispersal to continental Africa and a return to Madagascar. The L. madagascariensis group (also including a new candidate species identified herein) is the most basal clade in Lygodactylus, and the sister group of a clade with all the remaining species. The second most basal clade is the L. verticillatus group, placed as the sister group of a clade comprising African and Malagasy species. The sister lineage of the L. verticillatus group originated the African radiation through an oversea dispersal out of Madagascar. Eventually, the sister lineage of the L. capensis group originated secondary dispersals from Africa to Madagascar. In Madagascar, lineage diversification in different species groups mainly occurred from southern to northern and eastern regions. Dispersal, vicariance and paleoclimatic refugia probably played a relevant role in the evolutionary history of closely related taxa and in speciation mechanisms. The cytogenetic analysis evidenced a high karyotypic variability in Lygodactylus (from 2n = 34 to 2n = 40), which is at least partly consistent with the phylogenetic relationships and the composition of the various species group. Chromosome evolution occurred independently in different lineages, mainly through a reduction in the chromosome number and starting from a putative primitive karyotype of 2n = 40 with all telocentric elements.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Except for polyploidy, parthenogenesis and hybridogenesis, the role of chromosome rearrangements in speciation is still highly debated. This paper highlights an unusual karyotype diversification and ...a putative case of chromosomal speciation in the endemic Malagasy tomato frogs.
The tomato frogs include Dyscophus insularis as well as the sister species D. antongilii and D. guineti, which are characterized by a disjunct distribution and a low genetic divergence, probably due to a recent hybridization. Our results show that the three Dyscophus species present 2n=26 biarmed chromosomes, differing in chromatin pattern. Interestingly, both sexes of D. guineti show a heteromorphic chromosome pair 11, with one element larger (11a) than the other (11b) due to the presence of a large terminal tract on the short arm with an euchromatic band enclosed between two heterochromatic bands. This fixed condition reminds that of some newts of the genus Triturus, but in Dyscophus it probably characterizes the beginning of a cladogenetic process. We hypothesize that in D. guineti the raising of the heteromorphic 11th chromosome pair followed the hybridization with D. antongilii, originating a post-zygotic barrier and representing a case of sympatric or parapatric chromosomal speciation. This speciation mechanism may also have had important biogeographic consequences, shaping the current disjunct distribution of D. antongilii and D. guineti, so far not sufficiently explained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We compared chromosome morphologies for 11 species of Malagasy poison frogs, genus Mantella, and three outgroup taxa (genus Mantidactylus) using conventional and fluorescence staining techniques. All ...species studied had a karyotype of 2n=26, with five larger and eight smaller chromosome pairs. The 11th pair was acrocentic in Mantella nigricans which represents the first such observation in the genus. The nucleolus organizer region (NOR) was located at secondary constrictions on chromosome pair 2 in all Mantella studied and in Mantidactylus grandisonae (while located on other chromosomes in all other species of Mantidactylus studied so far). Heterochromatin distribution was highly variable among Mantella species; C-bands positively staining with DAPI and CMA3 were observed. The possible structure of these bands, seemingly containing both A+T rich and C+G rich heterochromatin, is discussed. Phylogenetic reconstruction using chromosomal characters provided very little information. Evolution of the characters studied is probably either too fast (heterochromatin arrangement) or too slow (NOR location) to match the main cladogenetic events among Mantella species groups.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We conducted a phylogenetic study through karyological data, by standard staining and Ag-NOR banding, and molecular analysis (by 12S and 16S mitochondrial rRNA genes and nuclear gene C-mos) on 11 ...species of Malagasy geckos, genus Paroedura, and two relatives (Ebenavia inunguis and Uroplatus phantasticus). Ebenavia inunguis and 17. phantasticus had 2n = 36 telocentric elements, NORs on the first chromosome pair in E. inunguis, and on the third chromosome pair in U. phantasticus. All examined Paroedura showed NORs on the smallest chromosome pair; moreover, six of the eleven examined species show a 2n = 36 karyotype, with a pair of metacentrics and 17 telocentric pair. The remaining species exhibited karyotypes with a diploid chromosome number ranging from 2n = 31 to 2n = 38. We assume that these karyotype assemblages derived from the 2n = 36 karyotype by cryptic and/or simple rearrangements, such as inversions, fissions and fusions. Furthermore, molecular and/or chromosomal data indicate that Paroedura is a monophyletic genus, in which chromosome rearrangements occurred repeatedly and independently during the specific diversification. Moreover both P. bastardi and P. gracilis in current definitions are paraphyletic assemblages of several related species, since their population proves more closely related to P. ibityensis or P. oviceps than co-specific populations. Key words: chromosome, Gekkonidae, Madagascar, Paroedura, molecular phylogeny.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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