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Tariq Ezaz - One of the best experts on this subject based on the ideXlab platform.
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Molecular cytogenetic map of the central bearded dragon, Pogona vitticeps (Squamata: Agamidae)
Chromosome Research, 2013Co-Authors: M. J. Young, D. O’meally, A. Georges, Tariq EzazAbstract:Reptiles, as the sister group to birds and mammals, are particularly valuable for comparative genomic studies among amniotes. The Australian central bearded dragon ( Pogona vitticeps ) is being developed as a reptilian model for such comparisons, with whole-genome sequencing near completion. The karyotype consists of 6 pairs of macrochromosomes and 10 pairs microchromosomes (2 n = 32), including a female heterogametic ZW sex microchromosome pair. Here, we present a molecular cytogenetic map for P . vitticeps comprising 87 anchor bacterial artificial chromosome clones that together span each macro- and microchromosome. It is the first comprehensive cytogenetic map for any non-avian reptile. We identified an active nucleolus organizer region (NOR) on the sub-telomeric region of 2q by mapping 18S rDNA and Ag-NOR staining. We identified interstitial telomeric sequences in two microchromosome pairs and the W chromosome, indicating that microchromosome fusion has been a mechanism of karyotypic evolution in Australian agamids within the last 21 to 19 million years. Orthology searches against the chicken genome revealed an intrachromosomal rearrangement of P . vitticeps 1q, identified regions orthologous to chicken Z on P . vitticeps 2q, snake Z on P . vitticeps 6q and the autosomal microchromosome pair in P . vitticeps orthologous to turtle Pelodiscus sinensis ZW and lizard Anolis carolinensis XY. This cytogenetic map will be a valuable reference tool for future gene mapping studies and will provide the framework for the work currently underway to physically anchor genome sequences to chromosomes for this model Australian squamate.
M. J. Young - One of the best experts on this subject based on the ideXlab platform.
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Molecular cytogenetic map of the central bearded dragon, Pogona vitticeps (Squamata: Agamidae)
Chromosome Research, 2013Co-Authors: M. J. Young, D. O’meally, A. Georges, Tariq EzazAbstract:Reptiles, as the sister group to birds and mammals, are particularly valuable for comparative genomic studies among amniotes. The Australian central bearded dragon ( Pogona vitticeps ) is being developed as a reptilian model for such comparisons, with whole-genome sequencing near completion. The karyotype consists of 6 pairs of macrochromosomes and 10 pairs microchromosomes (2 n = 32), including a female heterogametic ZW sex microchromosome pair. Here, we present a molecular cytogenetic map for P . vitticeps comprising 87 anchor bacterial artificial chromosome clones that together span each macro- and microchromosome. It is the first comprehensive cytogenetic map for any non-avian reptile. We identified an active nucleolus organizer region (NOR) on the sub-telomeric region of 2q by mapping 18S rDNA and Ag-NOR staining. We identified interstitial telomeric sequences in two microchromosome pairs and the W chromosome, indicating that microchromosome fusion has been a mechanism of karyotypic evolution in Australian agamids within the last 21 to 19 million years. Orthology searches against the chicken genome revealed an intrachromosomal rearrangement of P . vitticeps 1q, identified regions orthologous to chicken Z on P . vitticeps 2q, snake Z on P . vitticeps 6q and the autosomal microchromosome pair in P . vitticeps orthologous to turtle Pelodiscus sinensis ZW and lizard Anolis carolinensis XY. This cytogenetic map will be a valuable reference tool for future gene mapping studies and will provide the framework for the work currently underway to physically anchor genome sequences to chromosomes for this model Australian squamate.
Yoshinori Kumazawa - One of the best experts on this subject based on the ideXlab platform.
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Mitochondrial DNA Variability within Uromastyx ornata philbyi (Agamidae: Squamata) from Southwestern Saudi Arabia
Hindawi Limited, 2012Co-Authors: Sayed A. M. Amer, Mohamed M. Ahmed, Thomas M. Wilms, Mohammed Shobrak, Yoshinori KumazawaAbstract:Approximately 2.4 kbp of mitochondrial DNA was sequenced from 9 individuals of Uromastyx ornata philbyi originating from Taif, Namas, Al-Baha, and Jazan in southwestern Saudi Arabia. The sequenced regions cover eight tRNA genes (tRNAGln, tRNAIle, tRNAMet, tRNATrp, tRNAAla, tRNAAsn, tRNACys, and tRNATyr) and two protein-coding genes (NADH dehydrogenase subunit 2 and cytochrome b). U. ornata philbyi had an insertion of 170 bp length between tRNAGln and tRNAIle genes. The first 128 bp of this insertion was similar to the one identified earlier in U. ornata ornata and can be folded into a stem-and-loop structure, which was less stable in U. ornata philbyi than in U. ornata ornata, or the second tRNAGln gene. The next 42 bp of the insertion was unique in U. ornata philbyi and additionally retained a stable stem-and-loop structure. Most base substitutions found in the sequenced genes were synonymous transitions rather than transversions. Tree analyses supported the sister group relationship between the two U. ornata subspecies and divided U. ornata philbyi into two groups: Taif+Namas group in the east of Sarawat and Al-Baha+Jazan group in the west of Sarawat. These molecular data are in agreement with current classification of U. ornata
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Mitochondrial genomes of acrodont lizards: timing of gene rearrangements and phylogenetic and biogeographic implications
BMC Evolutionary Biology, 2010Co-Authors: Yasuhisa Okajima, Yoshinori KumazawaAbstract:Background Acrodonta consists of Agamidae and Chamaeleonidae that have the characteristic acrodont dentition. These two families and Iguanidae sensu lato are members of infraorder Iguania. Phylogenetic relationships and historical biogeography of iguanian lizards still remain to be elucidated in spite of a number of morphological and molecular studies. This issue was addressed by sequencing complete mitochondrial genomes from 10 species that represent major lineages of acrodont lizards. This study also provided a good opportunity to compare molecular evolutionary modes of mitogenomes among different iguanian lineages. Results Acrodontan mitogenomes were found to be less conservative than iguanid counterparts with respect to gene arrangement features and rates of sequence evolution. Phylogenetic relationships were constructed with the mitogenomic sequence data and timing of gene rearrangements was inferred on it. The result suggested highly lineage-specific occurrence of several gene rearrangements, except for the translocation of the tRNA^Pro gene from the 5' to 3' side of the control region, which likely occurred independently in both agamine and chamaeleonid lineages. Phylogenetic analyses strongly suggested the monophyly of Agamidae in relation to Chamaeleonidae and the non-monophyly of traditional genus Chamaeleo within Chamaeleonidae. Uromastyx and Brookesia were suggested to be the earliest shoot-off of Agamidae and Chamaeleonidae, respectively. Together with the results of relaxed-clock dating analyses, our molecular phylogeny was used to infer the origin of Acrodonta and historical biogeography of its descendant lineages. Our molecular data favored Gondwanan origin of Acrodonta, vicariant divergence of Agamidae and Chamaeleonidae in the drifting India-Madagascar landmass, and migration of the Agamidae to Eurasia with the Indian subcontinent, although Laurasian origin of Acrodonta was not strictly ruled out. Conclusions We detected distinct modes of mitogenomic evolution among iguanian families. Agamidae was highlighted in including a number of lineage-specific mitochondrial gene rearrangements. The mitogenomic data provided a certain level of resolution in reconstructing acrodontan phylogeny, although there still remain ambiguous relationships. Our biogeographic implications shed a light on the previous hypothesis of Gondwanan origin of Acrodonta by adding some new evidence and concreteness.
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mitochondrial genomes of acrodont lizards timing of gene rearrangements and phylogenetic and biogeographic implications
BMC Evolutionary Biology, 2010Co-Authors: Yasuhisa Okajima, Yoshinori KumazawaAbstract:Acrodonta consists of Agamidae and Chamaeleonidae that have the characteristic acrodont dentition. These two families and Iguanidae sensu lato are members of infraorder Iguania. Phylogenetic relationships and historical biogeography of iguanian lizards still remain to be elucidated in spite of a number of morphological and molecular studies. This issue was addressed by sequencing complete mitochondrial genomes from 10 species that represent major lineages of acrodont lizards. This study also provided a good opportunity to compare molecular evolutionary modes of mitogenomes among different iguanian lineages. Acrodontan mitogenomes were found to be less conservative than iguanid counterparts with respect to gene arrangement features and rates of sequence evolution. Phylogenetic relationships were constructed with the mitogenomic sequence data and timing of gene rearrangements was inferred on it. The result suggested highly lineage-specific occurrence of several gene rearrangements, except for the translocation of the tRNAPro gene from the 5' to 3' side of the control region, which likely occurred independently in both agamine and chamaeleonid lineages. Phylogenetic analyses strongly suggested the monophyly of Agamidae in relation to Chamaeleonidae and the non-monophyly of traditional genus Chamaeleo within Chamaeleonidae. Uromastyx and Brookesia were suggested to be the earliest shoot-off of Agamidae and Chamaeleonidae, respectively. Together with the results of relaxed-clock dating analyses, our molecular phylogeny was used to infer the origin of Acrodonta and historical biogeography of its descendant lineages. Our molecular data favored Gondwanan origin of Acrodonta, vicariant divergence of Agamidae and Chamaeleonidae in the drifting India-Madagascar landmass, and migration of the Agamidae to Eurasia with the Indian subcontinent, although Laurasian origin of Acrodonta was not strictly ruled out. We detected distinct modes of mitogenomic evolution among iguanian families. Agamidae was highlighted in including a number of lineage-specific mitochondrial gene rearrangements. The mitogenomic data provided a certain level of resolution in reconstructing acrodontan phylogeny, although there still remain ambiguous relationships. Our biogeographic implications shed a light on the previous hypothesis of Gondwanan origin of Acrodonta by adding some new evidence and concreteness.
A. Georges - One of the best experts on this subject based on the ideXlab platform.
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Molecular cytogenetic map of the central bearded dragon, Pogona vitticeps (Squamata: Agamidae)
Chromosome Research, 2013Co-Authors: M. J. Young, D. O’meally, A. Georges, Tariq EzazAbstract:Reptiles, as the sister group to birds and mammals, are particularly valuable for comparative genomic studies among amniotes. The Australian central bearded dragon ( Pogona vitticeps ) is being developed as a reptilian model for such comparisons, with whole-genome sequencing near completion. The karyotype consists of 6 pairs of macrochromosomes and 10 pairs microchromosomes (2 n = 32), including a female heterogametic ZW sex microchromosome pair. Here, we present a molecular cytogenetic map for P . vitticeps comprising 87 anchor bacterial artificial chromosome clones that together span each macro- and microchromosome. It is the first comprehensive cytogenetic map for any non-avian reptile. We identified an active nucleolus organizer region (NOR) on the sub-telomeric region of 2q by mapping 18S rDNA and Ag-NOR staining. We identified interstitial telomeric sequences in two microchromosome pairs and the W chromosome, indicating that microchromosome fusion has been a mechanism of karyotypic evolution in Australian agamids within the last 21 to 19 million years. Orthology searches against the chicken genome revealed an intrachromosomal rearrangement of P . vitticeps 1q, identified regions orthologous to chicken Z on P . vitticeps 2q, snake Z on P . vitticeps 6q and the autosomal microchromosome pair in P . vitticeps orthologous to turtle Pelodiscus sinensis ZW and lizard Anolis carolinensis XY. This cytogenetic map will be a valuable reference tool for future gene mapping studies and will provide the framework for the work currently underway to physically anchor genome sequences to chromosomes for this model Australian squamate.
D. O’meally - One of the best experts on this subject based on the ideXlab platform.
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Molecular cytogenetic map of the central bearded dragon, Pogona vitticeps (Squamata: Agamidae)
Chromosome Research, 2013Co-Authors: M. J. Young, D. O’meally, A. Georges, Tariq EzazAbstract:Reptiles, as the sister group to birds and mammals, are particularly valuable for comparative genomic studies among amniotes. The Australian central bearded dragon ( Pogona vitticeps ) is being developed as a reptilian model for such comparisons, with whole-genome sequencing near completion. The karyotype consists of 6 pairs of macrochromosomes and 10 pairs microchromosomes (2 n = 32), including a female heterogametic ZW sex microchromosome pair. Here, we present a molecular cytogenetic map for P . vitticeps comprising 87 anchor bacterial artificial chromosome clones that together span each macro- and microchromosome. It is the first comprehensive cytogenetic map for any non-avian reptile. We identified an active nucleolus organizer region (NOR) on the sub-telomeric region of 2q by mapping 18S rDNA and Ag-NOR staining. We identified interstitial telomeric sequences in two microchromosome pairs and the W chromosome, indicating that microchromosome fusion has been a mechanism of karyotypic evolution in Australian agamids within the last 21 to 19 million years. Orthology searches against the chicken genome revealed an intrachromosomal rearrangement of P . vitticeps 1q, identified regions orthologous to chicken Z on P . vitticeps 2q, snake Z on P . vitticeps 6q and the autosomal microchromosome pair in P . vitticeps orthologous to turtle Pelodiscus sinensis ZW and lizard Anolis carolinensis XY. This cytogenetic map will be a valuable reference tool for future gene mapping studies and will provide the framework for the work currently underway to physically anchor genome sequences to chromosomes for this model Australian squamate.