The karyology of the Iberian rock lizards (original) (raw)
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Italian Journal of Zoology, 2005
The results are presented of a chromosomal study performed by means standard and banding staining methods in the Mosor rock lizard, 'Lacerta' mosorensis, the last European mountain lizard to be karyotyped. It had a karyotype of 2n = 38 elements, 36 telocentric macrochromosomes + 2 microchromosomes, and NORs on peritelomeric regions of a medium-small chromosome pair. C-banding staining disclosed the presence of heteromorphic Z and W sex chromosomes. The W chromosome appeared to be completely heterochromatic and smaller than the Z one, which, instead, was mostly euchromatic. The results obtained show that 'L.' mosorensis is karyologically unrelated to other European mountain lizards, whose karyotypes display a different chromosome number and/or localization of NORs.
The karyotype of Lacerta horv�thi (Reptilia, Sauria, Lacertidae)
Genetica, 1989
The chromosomes of Lacerta horvfthi have been studied by means of conventional, C-banding, and silver-NOR techniques. The karyotype of this species, characterized by 36 acrocentric macrochromosomes, lacks the typical pair of microchromosomes shared by all other lacertid lizards. It is hypothesized that the microchromosomes could have been translocated to the large elements of the karyotype. The occurrence of such a rearrangement in the chromosome complement ofL. horvhthi underlines its isolation from the other species of the subgenus Archaeolacerta. The C-banding analysis evidences the existence of a female sex heteromorphism in which the W-chromosome has the same shape and size of the Z, but differs from it in being completely heterochromatic. The nucleolar organizer regions (NORs) are located on a pair of medium size chromosomes in subtelomeric position, where the standard Giemsa-staining reveals secondary constrictions.
… Journal of the …, 2011
Podarcis bocagei and Podarcis carbonelli are two species of wall lizards endemic to the western Iberian Peninsula. A detailed phylogeographical study based on mitochondrial DNA (mtDNA) variation has shown that they responded differently to the Quaternary climatic oscillations. These differences have been attributed to their distribution patterns: P. bocagei is distributed in the north of the Peninsula and in a continuous fashion, whereas P. carbonelli has a more southern and fragmented distribution. In this study, we assessed whether nuclear markers reveal similar evolutionary patterns to those inferred from mtDNA variation. We studied a battery of allozyme and microsatellite loci in a geographically representative set of individuals from both species. For each species we evaluated overall levels of differentiation, patterns of geographical variation in genetic diversity, genetic relationships amongst localities, and applied model-based individual multilocus genotype clustering approaches to detect hidden population structure. Our results for P. bocagei are highly concordant with the phylogeographical scenario inferred from mtDNA variation: we found very low levels of population differentiation, consistent with survival in a single glacial refugium, and detected signatures of a rapid demographic and geographical expansion. The analyses of nuclear markers furthermore helped to identify a probable refugial area, as well as expansion routes. Additionally, in concordance with observations based on mtDNA variation, a low level of population differentiation was observed in P. carbonelli, but this was significantly higher than in P. bocagei. However, the geographical basis for differentiation in P. carbonelli is highly inconsistent between mtDNA and nuclear markers, suggesting a complex, albeit recent, history of fragmentation. A recent reduction of this species' distribution has probably erased the signatures of glacial isolation and post-glacial expansion that are normally found in other Iberian species, suggesting that the currently observed pattern of genetic differentiation in this species was shaped more by recent genetic drift than by the Pleistocene climatic oscillations.
Rendiconti Lincei-scienze Fisiche E Naturali, 1991
The chromosome complement of Lacerta mosorensis was analyzed by means of conventional techniques in both somatic and spermatogonial metaphases. This species exhibits a typical lacertid karyotype, being characterized by the diploid number 2n = 38 (Fundamental Number = 38). In males the analysis of somatic metaphases reveals 36 acrocentric macrochromosomes and 2 microchromosomes (36 MI + 2m). In females all the examined somatic metaphases are characterized by 35 acrocentric macrochromosomes and 3 small dot-shaped microchromosomes (35 MI + 3 m). This result clearly indicates that in Lacerta mosorensis the female is heterogametic. The sex-determining mechanism is of the ZZ/ZW type; in the female karyotype the Z-chromosome is a large sized macrochromosome, while the W-chromosome is equal in size to the two micro-autosomes. Il cariotipo di Lacerta mosorensis è stato studiato utilizzando tecniche convenzionali di preparazione dei cromosomi da midollo osseo e testicoli. Il corredo cromosomico di questa specie è quello caratteristico dei Lacertidi: L. mosorensis è infatti caratterizzata da numero diploide 2n = 38 (Numero Fondamentale = 38). Nei maschi l’analisi delle metafasi somatiche rivela la presenza di 36 macrocromosomi acrocentrici e 2 microcromosomi (36 MI + 2m). Le metafasi somatiche delle femmine sono invece caratterizzate costantemente da 35 macrocromosomi acrocentrici e 3 microcromosomi (35 MI + 3 m). Ciò indica chiaramente che inLacerta mosorensis esiste eterogametia femminile. Il meccanismo di determinazione del sesso è del tipo ZZ/ZW. Il cromosoma Z del cariotipo femminile è un macrocromosoma di grandi dimensioni, mentre il cromosoma W è piuttosto piccolo ed ha dimensioni simili a quelle dei due micro-autosomi.