Figure 5 - uploaded by Tony Gamble
Content may be subject to copyright.
Source publication
The karyotypes of Malagasy geckos are poorly known. Herein, we describe the karyotypes of two Malagasy gecko species, Paroedura picta and an undescribed or currently unrecognised Paroedura species. These are the first karyotypes described for the genus Paroedura. Each species had a distinct karyotype; P. picta had 2n=36 and Paroedura sp. had 2n=34....
Context in source publication
Context 1
... gecko genus Paroedura consists of 16 described species and occurs on Madagascar and the Comoros (Nussbaum & Raxworthy 2000; Jackman et al. 2008). The biology of this genus is poorly known even though many species are kept as pets and one species, Paroedura picta , is commonly used as a model for studying development, physiology and behaviour (Brillet 1993; Blumberg et al. 2002; Kubicka & Kratochvil 2009; Noro et al. 2009; Starostova et al. 2010). New species continue to be discovered and several forms await description (Nussbaum & Raxworthy 2000; Glaw & Vences 2007; Jackman et al. 2008). This general lack of knowledge extends to cytogenetics as no Paroedura species have published karyotypes. Indeed, only seven species of Malagasy geckos have been karyotyped to date, all in the genus Phelsuma (Aprea et al. 1996). Herein, we describe the karyotypes of two Paroedura species and present evidence for another undescribed species in the genus that has not been identified in recent investigations of the group (Jackman et al. 2008). We acquired a captive-born male and female Paroedura picta and two males and two females of an undescribed species of Paroedura through the pet trade. Metaphase chromosome spreads were obtained from fibroblast tissue cultures derived from tail tissue. We cultured cells at 28 Á 30 8 C in DMEM 1X (Invitrogen, Carlsbad, CA, USA) with 4.5 g/l glucose and L-glutamine without sodium pyruvate, 20% foetal bovine serum and anti-anti (Invitrogen), which contains penicillin, streptomycin, and amphotericin. Cells were arrested in metaphase using vinblastine sulphate (1 g/ml) and incubated in hypotonic solution (0.07 M KCl) for 20 min at 37 8 C. After hypotonic treatment, cells were centrifuged and fixed in methanol:acetic acid (3:1). We washed the cell suspension in fresh fixative a total of five times. We also prepared meiotic chromosomes from the male P. picta . The male gecko was killed using an intraperitoneal injection of MS-222 dissolved in water (Conroy et al. 2009) and the testes were immediately removed into phosphate-buffered saline. Tissue was cut into small pieces and the cell suspension incubated in hypotonic solution (0.07 M KCl) for 30 min at 37 8 C. The cell suspension was centrifuged and fixed in methanol:acetic acid solution as above. Cell suspensions were dropped onto cleaned glass slides and air dried. Slides were stained with 4,6-diamidino-2-phenylindole (DAPI) and mounted with Perma?uor (Lab Vision) and a cover slip. We used reverse fluorescence counterstaining with chromomycin A3 (CA3) and DAPI to visualise GC-rich regions of the chromosomes (Schweizer 1976; Ezaz et al. 2005). We incubated slides for 3 h in a humid chamber at room temperature with 200 m l of 0.5 mg/ml of CA3 dissolved in McIlvaine’s buffer (pH 7.0). Slides were rinsed in McIlvaine’s buffer, stained with DAPI and mounted with Permafluor (Lab Vision) and a cover slip. We sequenced a fragment of mitochondrial DNA as a DNA ‘barcode’ (Hebert et al. 2004) to compare with sequences from a recent analysis of Paroedura phylogeny (Jackman et al. 2008) and confirm identification of the species used in this study. We chose the ND2 gene because it had the most Paroedura sequences available on Genbank for comparison. We extracted DNA from tissues from one P. picta and three Paroedura sp. (two of the karyotyped Paroedura sp. specimens and an additional, non-karyotyped, specimen Á MCZ-R189500) using the Qiagen DNeasy Blood and Tissue kit (Qiagen Inc., Venlo, The Netherlands) following the manufacturer’s instructions. We amplified a fragment of the mitochondrial ND2 gene using primers L4437b (5’-AAGCAGTTGGGCCCATRCC-3’) and H5934 (5’- AGRGTGCCAATGTCTTTGTGRTT-3’) (Macey et al. 1997). Polymerase chain reaction products were purified using Exonuclease I and Shrimp Alkaline Phospha- tase (Hanke & Wink 1994) and sequenced using Big Dye Terminator 3.1 chemistry on an ABI 3730xl at the Biomedical Genomics Center at the University of Minnesota. Sequences were assembled and checked for accuracy using Sequencher 4.8 (Gene Codes Corp., Ann Arbor, MI, USA). Protein coding sequences were aligned using ClustalW (Thompson et al. 1994) and DNA data translated to amino acids using MacClade 4.0.8 (Maddison & Maddison 1992) to confirm alignment and ensure there were no premature stop codons. Non-coding sequences were aligned using R-Coffee (Moretti et al. 2008), which uses predicted secondary structures when making the alignment. We conducted phylogenetic analysis of the ND2 data using partitioned maximum likelihood, implemented in RAxML 7.2.6 (Stamatakis 2006). Data were partitioned by codon with a fourth partition for tRNAs. All partitions were assigned the GTR ' G model of sequence evolution. We assessed nodal support using 100 non-parametric bootstrap replicates (Felsenstein 1985). We calculated net among group genetic distances in ND2 data among sampled Paroedura species. We calculated both uncorrected ( p ) distances and ML corrected distances, using the GTR ' G model, with standard errors calculated using 1 000 bootstrap replicates using MEGA 5.05 (Tamura et al. 2011). We examined between four and 20 metaphase spreads for each individual. Diploid chromosome number of P. picta was 36 (Figs. 1 Á 2). Paroedura picta had one pair of sub-metacentric chromosomes with the remaining chromosomes being acrocentric and gradually decreasing in size. Diploid chromosome number of Paroedura sp. was 34 (Fig 1). Paroedura sp . had two pairs of sub-metacentric chromosomes with remaining chromosomes acrocentric and gradually decreasing in size. Reverse fluorescence counterstaining showed no defined bands although some increased CA3 staining and decreased DAPI signal was found near centromeres and telomeres on larger chromosomes for both Paroedura species (Fig 3). This pattern is typical of staining with GC-specific fluorochromes in amphibians and reptiles (Schmid & Guttenbach 1988), including other gecko species such as Gekko gecko (Solleder & Schmid 1984) and Coleonyx elegans (Pokorn ́ et al. 2011). Phylogenetic relationships among Paroedura species from ND2 data (Fig 4) were largely congruent with results from Jackman et al. (2008). DNA sequence data confirmed the identification of the P. picta specimen sequenced, which formed a well- supported clade with other P. picta sequences. Paroedura sp . formed a clade with P. bastardi , P. ibityensis, P. tanjaka and another undescribed Paroedura species from Tsingy de Bemaraha ( Paroedura sp. 2). Paroedura sp. does not belong to any of the other sampled species in the genus and uncorrected genetic distances between Paroedura sp. and other sampled Paroedura species ranged from 18 Á 31% (Table 1). No heteromorphic sex chromosomes were evident in either of the Paroedura species we examined. Paroedura picta has been shown to have genotypic sex determination based on incubation experiments (Blumberg et al. 2002). Although we did not observe sex chromosomes with DAPI or CA3 staining, additional cytogenetic methods such as comparative genomic hybridisation, as described by Ezaz et al. (2005), may prove useful to confirm the presence of sex chromosomes. Paroedura shares some superficial cytogenetic similarities with other related gecko species. Paroedura belongs to a clade of Afro-Madagascan geckos (Joger 1985; Gamble et al. 2011) and other karyotyped species in this group, including Phelsuma , Homopholis and Chondrodactylus , like P. picta , have 36 pairs of chromosomes (De Smet 1981; Aprea et al. 1996). The similarity ends with chromosome number, however, and all of these genera differ substantially in fundamental number and chromosomal morphology (De Smet 1981; Aprea et al. 1996). The nine species of karyotyped Phelsuma all have karyotypes consisting solely of acrocentric chromosomes (Aprea et al. 1996). Homopholis wahlbergii has a 2n 0 36 karyotype with three pairs of sub-metacentric chromosomes and one pair of metacentric chromosomes (De Smet 1981). Chondrodactylus bibronii also has a 2n 0 36 karyotype but has one pair of sub-metacentric chromosomes, three pairs of sub-telocentric chromosomes and four pairs of metacentric chromosomes (De Smet 1981). The relative stability of chromosome number in this group belies an underlying variability and numerous rearrangements. This variation extends to our observations within Paroedura . The 2n 0 34 karyotype of Paroedura sp. can be derived from the P. picta 2n 0 36 by a fusion of two chromosome pairs. Conversely, the 2n 0 36 karyotype of P. picta can be derived by a fission of the sub-metacentric pair of chromosomes in Paroedura sp., 2n 0 34. Differentiating between these two scenarios will require cytogenetic data from additional Paroedura species and other related Afro-Madagascan geckos. These results add further evidence for the underestimation of species diversity in Madagascar (Glaw & Vences 2007; Vieites et al. 2009) and highlight the need for additional herpetological surveys in the region. Phylogenetic analyses of mtDNA confirmed that Paroedura sp . forms a well-supported clade with P. bastardi , P. ibityensis , P. tanjaka and an additional undescribed species ( Paroedura sp. 2). Paroedura sp. (Fig 5) most closely resembles P. ibityensis although it shares some similarity to juvenile P. bastardi . Ultimately, further research will be necessary to confirm the identity of the undescribed or unrecognised Paroedura species examined ...
Similar publications
Ringkasan
Kadal Cryptoblepharus termasuk di dalam Suku Scincidae (Kadal Berkulit-licin) dan mempunyai keunikan pada kelopak matanya yang tidak dapat digerakkan, seperti halnya pada mata ular. Terdapat tujuh jenis kadal ini di Indonesia dengan persebaran yang terbatas hanya di pulau-pulau di bagian selatan Garis Khatulistiwa. Kerabat terdekat kadal-...
Der Beitrag gibt Anregungen zur Erarbeitung von Struktur-Eigenschaftsbeziehungen im Kontext Bionik. Dabei wird insbesondere der Wechsel der verschiedenen Betrachtungs- und Erklärungsebenen von makroskopischen Phänomenen über Oberflächenstrukturen bis zu molekularen Wechselwirkungen angeregt. Das Konzept ist fächerverbindend angelegt und bezieht The...
Available at: http://www.amazon.com/The-Biology-Chameleons-Krystal-Tolley/dp/0520276051/
The Reserva Biológica Tamboré (RBT) is a conservation area of Atlantic Forest in the municipality of Santana do Parnaíba,at the urban perimeter of São Paulo, Brazil. We performed a herpetofaunal survey of RBT using active and passive trappingmethods. We recorded 357 anuran specimens of 26 species, and 53 reptile specimens (six species of lizards an...
Citations
... In the first chromosome analyses on the genus, Main et al. [12] and Aprea et al. [13] described the karyotypes of 2 and 11 species, respectively, including several taxa of the P. bastardi and P. picta species groups. These studies show that the genus is characterized by a karyotype composed of 2n = 31-38 mostly acrocentric chromosomes, with NORs always localized on microchromosome pairs and the occurrence of a putative multiple sex chromosome system with female heterogamety (Z 1 Z 1 Z 2 Z 2 /Z 1 Z 2 W) in P. gracilis. ...
We present a comparative chromosome study of several taxa of the Malagasy ground geckos of the Paroedura bastardi and P. picta species groups. We employed a preliminary molecular analysis using a trait of the mitochondrial 16S rRNA gene (of about 570 bp) to assess the taxonomic status of the samples studied and a cytogenetic analysis with standard karyotyping (5% Giemsa solution), silver staining (Ag–NOR staining) and sequential C-banding (C-banding + Giemsa and + fluorochromes). Our results show that all the taxa studied of the P. bastardi group (P. ibityensis, P. rennerae and P. cf. guibeae) have a similar karyotype composed of 2n = 34 chromosomes, with two metacentric pairs (1 and 3) and all other pairs being acrocentric. Chromosome diversification in the P. bastardi group was mainly linked to the diversification of heteromorphic sex chromosome systems (ZZ/ZW) in P. ibityensis and P. rennerae, while no heteromorphic sex chromosome pair was found in P. cf. guibeae. The two taxa investigated of the P. picta species group (here named P. picta and P. cf. picta based on molecular data) showed the same chromosome number of 2n = 36, mostly acrocentric elements, but differed in the number of metacentric elements, probably as a result of an inversion at chromosome pair 2. We highlight that the genus Paroedura is characterized by the independent diversification of heterogametic sex chromosomes in different evolutionary lineages and, similarly to other phylogenetically related gecko genera, by a progressive formation of a biarmed element by means of tandem fusions and inversions of distinct pairs.
... Chromosome pairs in all four reptile species largely differ in size (Figure 1). The chromosome complement of the reptiles herein varied: 2n = 32 chromosomes in the bearded dragon (6 pairs of macro chromosomes and 10 pairs of micros, including the sex chromosomes) (Young et al., 2013), 2n = 32 in the western-banded gecko (16 pairs of acrocentric chromosomes with continuous decreasing of size from large to small) (Pokorná et al., 2010), 2n = 36 chromosomes continuously decreasing in size in the ocelot gecko (Main et al., 2012;Koubová et al., 2014) and 2n = 50 in the painted turtle (13 pairs of macro chromosomes and 12 pairs of micros) (Badenhorst et al., 2015) ( Figure 1B). ...
During meiotic prophase I, tightly regulated processes take place, from pairing and synapsis of homologous chromosomes to recombination, which are essential for the generation of genetically variable haploid gametes. These processes have canonical meiotic features conserved across different phylogenetic groups. However, the dynamics of meiotic prophase I in non-mammalian vertebrates are poorly known. Here, we compare four species from Sauropsida to understand the regulation of meiotic prophase I in reptiles: the Australian central bearded dragon (Pogona vitticeps), two geckos (Paroedura picta and Coleonyx variegatus) and the painted turtle (Chrysemys picta). We first performed a histological characterization of the spermatogenesis process in both the bearded dragon and the painted turtle. We then analyzed prophase I dynamics, including chromosome pairing, synapsis and the formation of double strand breaks (DSBs). We show that meiosis progression is highly conserved in reptiles with telomeres clustering forming the bouquet, which we propose promotes homologous pairing and synapsis, along with facilitating the early pairing of micro-chromosomes during prophase I (i.e., early zygotene). Moreover, we detected low levels of meiotic DSB formation in all taxa. Our results provide new insights into reptile meiosis.
... No ITSs were identified (Fig. S1H). The karyotype of P. picta with 2n=36 and the distribution of telomeric sequences (Fig. S1I,J) in our specimens are identical with previous reports for this species (Main et al., 2012;Aprea et al., 2013;Koubová et al., 2014). ...
Obligate parthenogenesis evolved in reptiles convergently several times, mostly through interspecific hybridization. The obligate parthenogenetic complexes typically include both diploid and triploid lineages. Offspring of the parthenogenetic hybrids are genetic copies of their mothers; however, the cellular mechanism enabling the production of unreduced cells is largely unknown. Here, we document that oocytes go through meiosis in three widespread, or even strongly invasive, obligate parthenogenetic complexes of geckos, namely in diploid and triploid Lepidodactylus lugubris, and triploid Hemiphyllodactylus typus and Heteronotia binoei. In all these four lineages, the majority of oocytes enter the pachytene at the original ploidy level, but their chromosomes cannot pair properly and form univalents, bivalents and multivalents. Unreduced eggs with clonally inherited genomes are formed from germ cells that had undergone premeiotic endoreplication, where proper segregation is ensured by the formation of bivalents made from copies of identical chromosomes. We conclude that the induction of premeiotic endoreplication was in reptiles independently co-opted at least four times as an essential component of parthenogenetic reproduction and that this mechanism enables the emergence of fertile polyploid lineages within parthenogenetic complexes.
... Chromosome spreads from two males and two females of A. expectatus were prepared from fibroblasts established from tail clips following published lizard cell culture protocols (Ezaz et al., 2008;Gamble, Geneva, Glor, & Zarkower, 2014;Main, Scantlebury, Zarkower, & Gamble, 2012). Fibroblasts were grown at 28-31°C in media containing DMEM 1X (Invitrogen) with 4.5 g/L glucose and lglutamine without sodium pyruvate, 20% foetal bovine serum and anti-anti (Invitrogen), which contains penicillin, streptomycin and amphotericin. ...
Current understanding of sex chromosome evolution is largely dependent on species with highly degenerated, heteromorphic sex chromosomes, but by studying species with recently evolved or morphologically indistinct sex chromosomes we can greatly increase our understanding of sex chromosome origins, degeneration, and turnover. Here, we examine sex chromosome evolution and stability in the gecko genus Aristelliger. We used RADseq to identify sex‐specific markers and show that four Aristelliger species, spanning the phylogenetic breadth of the genus, share a conserved ZZ/ZW system syntenic with avian chromosome two. These conserved sex chromosomes contrast with many other gecko sex chromosome systems by showing a degree of stability among a group known for its dynamic sex determining mechanisms. Cytogenetic data from A. expectatus revealed homomorphic sex chromosomes with an accumulation of repetitive elements on the W chromosome. Taken together, the large number of female‐specific A. praesignis RAD markers and the accumulation of repetitive DNA on the A. expectatus W karyotype suggests that the Z and W chromosomes are highly differentiated despite their overall morphological similarity. We discuss this paradoxical situation and suggest that it may, in fact, be common in many animal species.
... Including the sequences of Cocca et al. (2018), our tree (Fig. 1) reveals the existence of 5-7 lineages within P. bastardi that might represent distinct species, and according to our unpublished observations, also P. tanjaka might contain further, currently unrecognized diversity. Beside morphological and genetic studies, karyological data (Main et al. 2012, Aprea et al. 2013, Koubová et al. 2014) might also contribute significantly to elucidate the taxonomy of this genus in an integrative approach (Padial et al. 2010). The recently published genome of Paroedura picta (Hara et al. 2018) will be a valuable resource in our understanding of the evolution in the genus. ...
We describe the new gecko species Paroedura neglecta sp. n. from the Tsingy de Bemaraha National Park in western Madagascar, belonging to the P. bastardi/tanjaka clade. The species in this clade are characterized by three light dorsal crossbands on the dorsum of juveniles and subadults whereas all other Paroedura species have four such bands. The new species differs from all species in the P. bastardi complex in having the nostril in contact with the rostral scale. It is most similar to the sympatric P. tanjaka, from which it differs by the presence of prominent dorsal tubercles arranged in regular longitudinal rows (versus rather irregular rows of dorsal tubercles), smaller size, details of the dorsal colour pattern and strong genetic divergence.
... This species has become a well-studied laboratory reptile for developmental biology, genetics, physiology and behavioural and evolutionary ecology (e.g. Kratochvíl et al., 2006Kratochvíl et al., , 2008Noro et al., 2009;Main et al., 2012;Zahradnícěk et al., 2012;Golinski et al., 2014;Tadashi et al., 2015). ...
Sexual size dimorphism (SSD) reflects sex-specific solutions to the allocation of energy among growth, reproduction and survival; however, the proximate mechanisms behind these solutions are still poorly known even in vertebrates. In squamates, sexual differences in body size used to be attributed to direct energy allocation to energetically demanding processes, largely to reproduction. In addition, SSD is assumed to be controlled by specific endogenous mechanisms regulating growth in a sex-specific manner, namely masculinization by male gonadal androgens, or feminization by ovarian hormones. We performed a manipulative growth experiment in females of the male-larger gecko Paroedura picta in order to test the reproductive cost hypothesis, the male androgen hypothesis and the ovarian hormone hypothesis. Specifically, we investigated the effect of total ovariectomy, prepubertal ovariectomy, unilateral ovariectomy, and total ovariectomy followed by exogenous estradiol, dihydrotestosterone or testosterone treatment, on female growth in comparison to males and reproductively active females. The present results and the results of our previous experiments did not support the hypotheses that SSD reflects direct energy allocation to reproduction and that male gonadal androgens are involved. On the other hand, all lines of evidence, particularly the comparable growth of reproducing intact and unilaterally ovariectomized females, were concordant with the control of SSD by ovarian hormones. We suggest that feminization of growth by female gonadal hormones should be taken into consideration as an endogenous pathway responsible for the ontogeny of SSD in squamates.
... Thanks to the extremely rapid reproduction (Weiser et al. 2012) and relatively easy laboratory housing and breeding, one species, Paroedura picta, has become an emerging model organism for thermal and reproductive physiology (e.g., Kubička et al. 2012;Starostová et al. 2012Starostová et al. , 2013 and developmental biology (Noro et al. 2009). Members of the genus were studied cytogenetically only relatively recently (Main et al. 2012;Aprea et al. 2013). Although it can be assumed from equal sex ratios across several constant incubation temperatures (Blumberg et al. 2002) and from sex ratios within clutches (Kratochvíl et al. 2008) that P. picta most likely has GSD and the presence of sex chromosomes should be expected, no sexual differences in karyotypes have been observed in any members of the genus (Main et al. 2012;Aprea et al. 2013), and therefore, the sexdetermining system remains unknown. ...
... Members of the genus were studied cytogenetically only relatively recently (Main et al. 2012;Aprea et al. 2013). Although it can be assumed from equal sex ratios across several constant incubation temperatures (Blumberg et al. 2002) and from sex ratios within clutches (Kratochvíl et al. 2008) that P. picta most likely has GSD and the presence of sex chromosomes should be expected, no sexual differences in karyotypes have been observed in any members of the genus (Main et al. 2012;Aprea et al. 2013), and therefore, the sexdetermining system remains unknown. However, only Giemsa staining and Ag-NOR visualization (Aprea et al. 2013) or DAPI and chromomycin A3 staining in two species (Main et al. 2012) were applied in previous cytogenetic studies of the genus, which might not have been enough to reveal the sex chromosomes. ...
... Although it can be assumed from equal sex ratios across several constant incubation temperatures (Blumberg et al. 2002) and from sex ratios within clutches (Kratochvíl et al. 2008) that P. picta most likely has GSD and the presence of sex chromosomes should be expected, no sexual differences in karyotypes have been observed in any members of the genus (Main et al. 2012;Aprea et al. 2013), and therefore, the sexdetermining system remains unknown. However, only Giemsa staining and Ag-NOR visualization (Aprea et al. 2013) or DAPI and chromomycin A3 staining in two species (Main et al. 2012) were applied in previous cytogenetic studies of the genus, which might not have been enough to reveal the sex chromosomes. ...
Among amniote vertebrates, geckos represent a clade with exceptional variability in sex determination; however, only a minority of species of this highly diverse group has been studied in this respect. Here, we describe for the first time a female heterogamety in the genus Paroedura, the group radiated in Madagascar and adjacent islands. We identified homomorphic ZZ/ZW sex chromosomes with a highly heterochromatic W chromosome in Paroedura masobe, Paroedura oviceps, Paroedura karstophila, Paroedura stumpffi, and Paroedura lohatsara. Comparative genomic hybridization (CGH) revealed that female-specific sequences are greatly amplified in the W chromosome of P. lohatsara and that P. gracilis seems to possess a derived system of multiple sex chromosomes. Contrastingly, neither CGH nor heterochromatin visualization revealed differentiated sex chromosomes in the members of the Paroedura picta-Paroedura bastardi-Paroedura ibityensis clade, which is phylogenetically nested within lineages with a heterochromatic W chromosome. As a sex ratio consistent with genotypic sex determination has been reported in P. picta, it appears that the members of the P. picta-P. bastardi-P. ibityensis clade possess homomorphic, poorly differentiated sex chromosomes and may represent a rare example of evolutionary loss of highly differentiated sex chromosomes. Fluorescent in situ hybridization (FISH) with a telomeric probe revealed a telomere-typical pattern in all species and an accumulation of telomeric sequences in the centromeric region of autosomes in P. stumpffi and P. bastardi. Our study adds important information for the greater understanding of the variability and evolution of sex determination in geckos and demonstrates how the geckos of the genus Paroedura provide an interesting model for studying the evolution of the sex chromosomes.
... We prepared chromosome spreads from both males and females of five Anolis species (A. carolinensis, A. sagrei, A. grahami, A. lineatopus, and A. distichus) from fibroblast cultures established from tail clips (Ezaz et al. 2008;Main et al. 2012). Cells were arrested in metaphase using vinblastine sulfate (1 mg/ml) for 2-3 h. ...
To explain the frequency and distribution of heteromorphic sex chromosomes in the lizard genus Anolis we compared the relative roles of sex chromosome conservation vs. turnover of sex determining mechanisms. We used model based comparative methods to reconstruct karyotype evolution and the presence of heteromorphic sex chromosomes onto a newly generated Anolis phylogeny. We found that heteromorphic sex chromosomes evolved multiple times in the genus. Fluorescent in situ hybridization (FISH) of repetitive DNA showed variable rates of Y chromosome degeneration among Anolis species and identified previously undetected, homomorphic sex chromosomes in two species. We confirmed homology of sex chromosomes in the genus by performing FISH of an X-linked BAC and qPCR of X-linked genes in multiple Anolis species sampled across the phylogeny. Taken together, these results are consistent with long-term conservation of sex chromosomes in the group. Our results pave the way to address additional questions related to Anolis sex chromosome evolution and describe a conceptual framework that can be used to evaluate the origins and evolution of heteromorphic sex chromosomes in other clades. This article is protected by copyright. All rights reserved.
... Note that for Brookesia, Gephyromantis and Phelsuma I present analyses including putative cryptic species that are not included in published checklists of species counts from which the final column is derived. Additionally, I agree with Main et al. [31] that there is at least one additional undescribed or unrecognized Paroedura that was not included by Crottini et al. [3], and as well as with Raxworthy et al. [26] that the taxon Uroplatus giganteus requires a more thorough systematic evaluation as it is not clearly differentiated from neighbouring populations of Uroplatus frimbriatus. MCCR analyses: ...
The evolutionary origins of Madagascar's biodiversity remain mysterious despite the fact that relative to land area, there is no other place with consistently high levels of species richness and endemism across a range of taxonomic levels. Most efforts to explain diversification on the island have focused on geographical models of speciation, but recent studies have begun to address the island's accumulation of species through time, although with conflicting results. Prevailing hypotheses for diversification on the island involve either constant diversification rates or scenarios where rates decline through time. Using relative-time-calibrated phylogenies for seven endemic vertebrate clades and a model-fitting framework, I find evidence that diversification rates have declined through time on Madagascar. I show that diversification rates have clearly declined throughout the history of each clade, and models invoking diversity-dependent reductions to diversification rates best explain the diversification histories for each clade. These results are consistent with the ecological theory of adaptive radiation, and, coupled with ancillary observations about ecomorphological and life-history evolution, strongly suggest that adaptive radiation was an important formative process for one of the most species-rich regions on the Earth. These results cast the Malagasy biota in a new light and provide macroevolutionary justification for conservation initiatives.
... So far, karyological data on Paroedura are available for P. picta and an undescribed Paroedura sp. molecularly related to P. bastardi species group (Main et al. 2012). The former species possesses 2n = 36 chromosomes, with the elements of third pair biarmed and the remainder telocentric; the Paroedura sp. ...
... Data for Malagasy geckoes other than the two species studied by Main et al. (2012) and those considered here are available only for species and subspecies of Phelsuma and Uroplatus (Aprea et al. 1996;Aprea 2006). The latter studies provided evidence that specific chromosome diversification in Phelsuma and Uroplatus occurred without modifications either in number and shape of their chromosome sets (in fact all examined taxa showed 2n = 36 elements, mostly Ts), in contrast to loci of NORs that extensively varied both in the number and/or position on the chromosomes. ...
... In P. bastardi no significant diversification was observed between samples from Marofandilia and Miandrivazo, which, in contrast, are highly differentiated from samples from Toliara and Ilakaka. Note that the sequence divergence values found by Main et al. (2012) for their Paroedura sp. specimens which are closely related to P. bastardi are similar to values found for P. bastardi specimens in this study. ...
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.
