The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Adam D. Leaché - One of the best experts on this subject based on the ideXlab platform.
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characterization of a pericentric inversion in plateau fence lizards sceloporus tristichus evidence from chromosome scale genomes
G3: Genes Genomes Genetics, 2021Co-Authors: Ana M Bedoya, Adam D. LeachéAbstract:Spiny lizards in the genus Sceloporus are a model system among squamate reptiles for studies of chromosomal evolution. While most Pleurodont iguanians retain an ancestral karyotype formula of 2n = 36 chromosomes, Sceloporus exhibits substantial karyotype variation ranging from 2n = 22 to 46 chromosomes. We present two annotated chromosome-scale genome assemblies for the Plateau Fence Lizard (Sceloporus tristichus) to facilitate research on the role of pericentric inversion polymorphisms on adaptation and speciation. Based on previous karyotype work using conventional staining, the S. tristichus genome is characterized as 2n = 22 with six pairs of macrochromosomes and five pairs of microchromosomes and a pericentric inversion polymorphism on chromosome 7 that is geographically variable. We provide annotated, chromosome-scale genomes for two lizards located at opposite ends of a dynamic hybrid zone that are each fixed for different inversion polymorphisms. The assembled genomes are 1.84-1.87 Gb (1.72 Gb for scaffolds mapping to chromosomes) with a scaffold N50 of 267.5 Mb. Functional annotation of the genomes resulted in ∼15K predicted gene models. Our assemblies confirmed the presence of a 4.62-Mb pericentric inversion on chromosome 7, which contains 62 annotated coding genes with known functions. In addition, we collected population genomics data using double digest RAD-sequencing for 44 S. tristichus to estimate population structure and phylogeny across the Colorado Plateau. These new genomic resources provide opportunities to perform genomic scans and investigate the formation and spread of pericentric inversions in a naturally occurring hybrid zone.
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characterization of a large pericentric inversion in plateau fence lizards sceloporus tristichus evidence from chromosome scale genomes
bioRxiv, 2020Co-Authors: Adam D. Leaché, Ana M BedoyaAbstract:Spiny lizards in the genus Sceloporus are a model system among squamate reptiles for studies of chromosomal evolution. While most Pleurodont iguanians retain an ancestral karyotype formula of 2n=36 chromosomes, Sceloporus exhibits substantial kary- otype variation ranging from 2n=22 to 2n=46 chromosomes. In this study, we present two annotated chromosome-scale genome assemblies for the Plateau Fence Lizard (Sceloporus tristichus) in order to facilitate research on the role of pericentric inversion polymorphisms on adaptation and speciation. Based on previous karyotype work using conventional staining, the S. tristichus genome is characterized as 2n=22 with 6 pairs of macrochromosomes and 5 pairs of microchromosomes with a large pericentric inversion polymorphism on chromosome seven that is geographically variable. We provide annotated, chromosome-scale genomes for two lizards located at opposite ends of a dynamic hybrid zone that are each fixed for different inversion polymorphisms. The assembled genomes are 1.84 to 1.87 Gb (1.72 Gb for scaffolds mapping to chromosomes) with a scaffold N50 of 267.5 Mb. Functional annotation of the genomes resulted in 65,417 annotated genes, 16,426 of which were deduced to have a function. We confirmed the presence of a 4.62 Mb pericentric inversion on chromosome seven, which contains 59 annotated coding genes with known functions. These new genomic resources provide opportunities to perform genomic scans and investigate the formation and spread of pericentric inversions in a naturally occurring hybrid zone. Key words: chromosome rearrangement, de novo assembly, hybrid zone, pericentric inversion, phrynosomatidae, Sceloporus, genome sequencing.
Ana M Bedoya - One of the best experts on this subject based on the ideXlab platform.
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characterization of a pericentric inversion in plateau fence lizards sceloporus tristichus evidence from chromosome scale genomes
G3: Genes Genomes Genetics, 2021Co-Authors: Ana M Bedoya, Adam D. LeachéAbstract:Spiny lizards in the genus Sceloporus are a model system among squamate reptiles for studies of chromosomal evolution. While most Pleurodont iguanians retain an ancestral karyotype formula of 2n = 36 chromosomes, Sceloporus exhibits substantial karyotype variation ranging from 2n = 22 to 46 chromosomes. We present two annotated chromosome-scale genome assemblies for the Plateau Fence Lizard (Sceloporus tristichus) to facilitate research on the role of pericentric inversion polymorphisms on adaptation and speciation. Based on previous karyotype work using conventional staining, the S. tristichus genome is characterized as 2n = 22 with six pairs of macrochromosomes and five pairs of microchromosomes and a pericentric inversion polymorphism on chromosome 7 that is geographically variable. We provide annotated, chromosome-scale genomes for two lizards located at opposite ends of a dynamic hybrid zone that are each fixed for different inversion polymorphisms. The assembled genomes are 1.84-1.87 Gb (1.72 Gb for scaffolds mapping to chromosomes) with a scaffold N50 of 267.5 Mb. Functional annotation of the genomes resulted in ∼15K predicted gene models. Our assemblies confirmed the presence of a 4.62-Mb pericentric inversion on chromosome 7, which contains 62 annotated coding genes with known functions. In addition, we collected population genomics data using double digest RAD-sequencing for 44 S. tristichus to estimate population structure and phylogeny across the Colorado Plateau. These new genomic resources provide opportunities to perform genomic scans and investigate the formation and spread of pericentric inversions in a naturally occurring hybrid zone.
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characterization of a large pericentric inversion in plateau fence lizards sceloporus tristichus evidence from chromosome scale genomes
bioRxiv, 2020Co-Authors: Adam D. Leaché, Ana M BedoyaAbstract:Spiny lizards in the genus Sceloporus are a model system among squamate reptiles for studies of chromosomal evolution. While most Pleurodont iguanians retain an ancestral karyotype formula of 2n=36 chromosomes, Sceloporus exhibits substantial kary- otype variation ranging from 2n=22 to 2n=46 chromosomes. In this study, we present two annotated chromosome-scale genome assemblies for the Plateau Fence Lizard (Sceloporus tristichus) in order to facilitate research on the role of pericentric inversion polymorphisms on adaptation and speciation. Based on previous karyotype work using conventional staining, the S. tristichus genome is characterized as 2n=22 with 6 pairs of macrochromosomes and 5 pairs of microchromosomes with a large pericentric inversion polymorphism on chromosome seven that is geographically variable. We provide annotated, chromosome-scale genomes for two lizards located at opposite ends of a dynamic hybrid zone that are each fixed for different inversion polymorphisms. The assembled genomes are 1.84 to 1.87 Gb (1.72 Gb for scaffolds mapping to chromosomes) with a scaffold N50 of 267.5 Mb. Functional annotation of the genomes resulted in 65,417 annotated genes, 16,426 of which were deduced to have a function. We confirmed the presence of a 4.62 Mb pericentric inversion on chromosome seven, which contains 59 annotated coding genes with known functions. These new genomic resources provide opportunities to perform genomic scans and investigate the formation and spread of pericentric inversions in a naturally occurring hybrid zone. Key words: chromosome rearrangement, de novo assembly, hybrid zone, pericentric inversion, phrynosomatidae, Sceloporus, genome sequencing.
Gregory P Wilson - One of the best experts on this subject based on the ideXlab platform.
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a new late cretaceous iguanomorph from north america and the origin of new world Pleurodonta squamata iguania
Proceedings of The Royal Society B: Biological Sciences, 2017Co-Authors: David G. Demar, David J Varricchio, Jack L Conrad, Jason J Head, Gregory P WilsonAbstract:NSF (EAR) grant nos. 0847777 to D.J.V. and 1325674 to G.P.W., D.J.V. and J.L.C. Richard Gilder Graduate School and the American Museum of Natural History Collections Study Grant and the NSF GRFP grant no. DGE-0718124, both to D.G.D.
Aaron R H Leblanc - One of the best experts on this subject based on the ideXlab platform.
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tooth attachment and Pleurodont implantation in lizards histology development and evolution
Journal of Anatomy, 2021Co-Authors: Aaron R H Leblanc, Ilaria Paparella, Denis O Lamoureux, Michael R Doschak, Michael W CaldwellAbstract:Squamates present a unique challenge to the homology and evolution of tooth attachment tissues. Their stereotypically Pleurodont teeth are fused in place by a single "bone of attachment", with seemingly dubious homology to the three-part tooth attachment system of mammals and crocodilians. Despite extensive debate over the interpretations of squamate Pleurodonty, its phylogenetic significance, and the growing evidence from fossil amniotes for the homology of tooth attachment tissues, few studies have defined Pleurodonty on histological grounds. Using a sample of extant squamate teeth that we organize into three broad categories of implantation, we investigate the histological and developmental properties of their dental tissues in multiple planes of section. We use these data to demonstrate the specific soft- and hard-tissue features of squamate teeth that produce their disparate tooth implantation modes. In addition, we describe cementum, periodontal ligaments, and alveolar bone in Pleurodont squamates, dental tissues that were historically thought to be restricted to extant mammals and crocodilians. Moreover, we show how the differences between Pleurodonty and thecodonty do not relate to the identity of the tooth attachment tissues, but rather the arrangements of homologous tissues around the teeth.
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evolutionary implications of tooth attachment versus tooth implantation a case study using dinosaur crocodilian and mammal teeth
Journal of Vertebrate Paleontology, 2017Co-Authors: Aaron R H Leblanc, Kirstin S Brink, Thomas M. Cullen, Robert R. ReiszAbstract:ABSTRACTTooth attachment and implantation are two classical descriptors of dental anatomy. Tooth attachment distinguishes between teeth that are either fused to the jaw by bone, or suspended within a socket by a periodontal ligament. Tooth implantation describes the geometry of this attachment and has been broadly divided into acrodonty, Pleurodonty, and thecodonty. Among extant amniotes, only mammals and crocodilians are considered truly thecodont, because they possess a complex attachment system that includes a periodontal ligament and true tooth sockets. These two amniote groups diverged from a common ancestor over 300 million years ago and are thought to have evolved thecodonty independently. This view has recently come under a great deal of scrutiny with the discovery of complex tooth attachment systems, including the presence of a ligamentous tooth attachment in numerous non-mammalian, non-crocodilian amniotes. This has spurred debate and inconsistencies over the conventional usage of tooth attachme...
Martina Johnson Pokorna - One of the best experts on this subject based on the ideXlab platform.
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all iguana families with the exception of basilisks share sex chromosomes
Zoology, 2017Co-Authors: Marie Altmanova, Michail Rovatsos, Martina Johnson Pokorna, Milan Veselý, Florian Wagner, Lukas KratochvilAbstract:Abstract Once believed to be restricted only to endotherms (mammals and birds), several poikilothermic amniote lineages have recently been documented to possess long-term evolutionary stability in their sex chromosomes. However, many important lineages were not included in these tests. Previously, based on molecular evidence, we documented the homology of well-differentiated sex chromosomes among seven families of iguanas (Pleurodonta), with basilisks (Corytophanidae) being the only exception, as the tested genes linked to X, but missing on the Y chromosome, in other iguanas were autosomal or pseudoautosomal in basilisks. In this study, we test the homology of sex chromosomes in the remaining, previously unstudied iguana families (Hoplocercidae, Leiosauridae, Liolaemidae, Polychrotidae) and in the basilisk genus Corytophanes. Our results show that 12 currently recognized families of iguanas share X-specific gene content conserved from the common ancestor living in the Cretaceous period. However, the results in the genus Corytophanes indicate the loss of the ancestral differentiated sex chromosomes from the ancestor of basilisks. Our new data further confirm the extensive stability of sex chromosomes in iguanas, thus enabling molecular sexing based on the comparison of the number of X-specific genes by quantitative PCR (qPCR) in all but one family of this widely diversified clade.
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minute y chromosomes and karyotype evolution in madagascan iguanas squamata iguania opluridae
Biological Journal of The Linnean Society, 2016Co-Authors: Marie Altmanova, Michail Rovatsos, Lukas Kratochvil, Martina Johnson PokornaAbstract:Iguanas (Pleurodonta) are predominantly distributed in the New World, but one previously cytogenetically understudied family, Opluridae, is endemic to Madagascar and the adjacent Grand Comoro archipelago. The aim of our contribution is to fill a gap in the cytogenetic understanding of this biogeographically puzzling lineage. Based on examination of six species, we found that oplurids are rather conservative in karyotype, which is composed of 36 chromosomes as in most iguanas. However, the species differ in the position of the nucleolar organizer region and heterochromatic blocks and in the accumulation and distribution of interstitial telomeric sequences (ITSs), which suggests cryptic intra- and interchromosomal rearrangements. All tested species share the XY sex-determining system homologous to most other iguana families. The oplurid Y chromosome is degenerated, very small in size but mostly euchromatic. Fluorescence in situ hybridization with probes composed of microsatellite motifs revealed variability among species in the accumulation of particular repeats on the Y chromosome. This variability accounts for the differences in the detection of sex chromosomes across the species of the family using comparative genome hybridization (CGH) technique. Our study demonstrates the limits of the commonly used CGH technique to uncover sex chromosomes even in organisms with heteromorphic and sequentially largely differentiated sex chromosomes.