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1.
Cell ; 158(5): 1187-1198, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25171416

RESUMO

Programmed DNA rearrangements in the single-celled eukaryote Oxytricha trifallax completely rewire its germline into a somatic nucleus during development. This elaborate, RNA-mediated pathway eliminates noncoding DNA sequences that interrupt gene loci and reorganizes the remaining fragments by inversions and permutations to produce functional genes. Here, we report the Oxytricha germline genome and compare it to the somatic genome to present a global view of its massive scale of genome rearrangements. The remarkably encrypted genome architecture contains >3,500 scrambled genes, as well as >800 predicted germline-limited genes expressed, and some posttranslationally modified, during genome rearrangements. Gene segments for different somatic loci often interweave with each other. Single gene segments can contribute to multiple, distinct somatic loci. Terminal precursor segments from neighboring somatic loci map extremely close to each other, often overlapping. This genome assembly provides a draft of a scrambled genome and a powerful model for studies of genome rearrangement.


Assuntos
Rearranjo Gênico , Genoma de Protozoário , Oxytricha/crescimento & desenvolvimento , Oxytricha/genética , Núcleo Celular/metabolismo , Cromossomos/metabolismo , Dados de Sequência Molecular , Oxytricha/citologia , Oxytricha/metabolismo
2.
Development ; 151(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38345109

RESUMO

The field of developmental biology has declined in prominence in recent decades, with off-shoots from the field becoming more fashionable and highly funded. This has created inequity in discovery and opportunity, partly due to the perception that the field is antiquated or not cutting edge. A 'think tank' of scientists from multiple developmental biology-related disciplines came together to define specific challenges in the field that may have inhibited innovation, and to provide tangible solutions to some of the issues facing developmental biology. The community suggestions include a call to the community to help 'rebrand' the field, alongside proposals for additional funding apparatuses, frameworks for interdisciplinary innovative collaborations, pedagogical access, improved science communication, increased diversity and inclusion, and equity of resources to provide maximal impact to the community.


Assuntos
Biologia do Desenvolvimento
3.
Nature ; 616(7957): 440-441, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37045951

Assuntos
Rajidae , Animais
4.
Nature ; 558(7710): 445-448, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29899448

RESUMO

Haematopoietic stem and progenitor cells (HSPCs) require a specific microenvironment, the haematopoietic niche, which regulates HSPC behaviour1,2. The location of this niche varies across species, but the evolutionary pressures that drive HSPCs to different microenvironments remain unknown. The niche is located in the bone marrow in adult mammals, whereas it is found in other locations in non-mammalian vertebrates, for example, in the kidney marrow in teleost fish. Here we show that a melanocyte umbrella above the kidney marrow protects HSPCs against ultraviolet light in zebrafish. Because mutants that lack melanocytes have normal steady-state haematopoiesis under standard laboratory conditions, we hypothesized that melanocytes above the stem cell niche protect HSPCs against ultraviolet-light-induced DNA damage. Indeed, after ultraviolet-light irradiation, unpigmented larvae show higher levels of DNA damage in HSPCs, as indicated by staining of cyclobutane pyrimidine dimers and have reduced numbers of HSPCs, as shown by cmyb (also known as myb) expression. The umbrella of melanocytes associated with the haematopoietic niche is highly evolutionarily conserved in aquatic animals, including the sea lamprey, a basal vertebrate. During the transition from an aquatic to a terrestrial environment, HSPCs relocated into the bone marrow, which is protected from ultraviolet light by the cortical bone around the marrow. Our studies reveal that melanocytes above the haematopoietic niche protect HSPCs from ultraviolet-light-induced DNA damage in aquatic vertebrates and suggest that during the transition to terrestrial life, ultraviolet light was an evolutionary pressure affecting the location of the haematopoietic niche.


Assuntos
Evolução Biológica , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/efeitos da radiação , Melanócitos/citologia , Melanócitos/efeitos da radiação , Nicho de Células-Tronco/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Animais , Organismos Aquáticos/classificação , Citoproteção/efeitos da radiação , Dano ao DNA/efeitos da radiação , Rim , Mutação , Petromyzon/classificação , Filogenia , Dímeros de Pirimidina/efeitos da radiação , Nicho de Células-Tronco/fisiologia , Peixe-Zebra/classificação , Peixe-Zebra/genética
5.
Nature ; 536(7615): 205-9, 2016 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-27487209

RESUMO

Genetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates, including more recently the genomes of archaic hominins. Not all regions of the genome, however, are equally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2 accounts for approximately 1% of cases of autism and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. Here we reconstruct the evolutionary history of the locus and identify bolA family member 2 (BOLA2) as a gene duplicated exclusively in Homo sapiens. We estimate that a 95-kilobase-pair segment containing BOLA2 duplicated across the critical region approximately 282 thousand years ago (ka), one of the latest among a series of genomic changes that dramatically restructured the locus during hominid evolution. All humans examined carried one or more copies of the duplication, which nearly fixed early in the human lineage--a pattern unlikely to have arisen so rapidly in the absence of selection (P < 0.0097). We show that the duplication of BOLA2 led to a novel, human-specific in-frame fusion transcript and that BOLA2 copy number correlates with both RNA expression (r = 0.36) and protein level (r = 0.65), with the greatest expression difference between human and chimpanzee in experimentally derived stem cells. Analyses of 152 patients carrying a chromosome 16p11. rearrangement show that more than 96% of breakpoints occur within the H. sapiens-specific duplication. In summary, the duplicative transposition of BOLA2 at the root of the H. sapiens lineage about 282 ka simultaneously increased copy number of a gene associated with iron homeostasis and predisposed our species to recurrent rearrangements associated with disease.


Assuntos
Cromossomos Humanos Par 16/genética , Variações do Número de Cópias de DNA/genética , Evolução Molecular , Predisposição Genética para Doença , Proteínas/genética , Animais , Transtorno Autístico/genética , Quebra Cromossômica , Duplicação Gênica , Homeostase/genética , Humanos , Ferro/metabolismo , Pan troglodytes/genética , Pongo/genética , Proteínas/análise , Recombinação Genética , Especificidade da Espécie , Fatores de Tempo
6.
Mol Cell Proteomics ; 19(1): 198-208, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31732549

RESUMO

The analysis of samples from unsequenced and/or understudied species as well as samples where the proteome is derived from multiple organisms poses two key questions. The first is whether the proteomic data obtained from an unusual sample type even contains peptide tandem mass spectra. The second question is whether an appropriate protein sequence database is available for proteomic searches. We describe the use of automated de novo sequencing for evaluating both the quality of a collection of tandem mass spectra and the suitability of a given protein sequence database for searching that data. Applications of this method include the proteome analysis of closely related species, metaproteomics, and proteomics of extinct organisms.


Assuntos
Bases de Dados de Proteínas , Proteoma/análise , Proteômica/métodos , Análise de Sequência de Proteína/métodos , Espectrometria de Massas em Tandem/métodos , Algoritmos , Sequência de Aminoácidos , Animais , Caenorhabditis elegans , Hemípteros , Humanos , Células K562 , Peptídeos/análise , Proteínas/análise , Rajidae , Software , Ursidae
7.
Nature ; 513(7518): 375-381, 2014 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-25186727

RESUMO

Cichlid fishes are famous for large, diverse and replicated adaptive radiations in the Great Lakes of East Africa. To understand the molecular mechanisms underlying cichlid phenotypic diversity, we sequenced the genomes and transcriptomes of five lineages of African cichlids: the Nile tilapia (Oreochromis niloticus), an ancestral lineage with low diversity; and four members of the East African lineage: Neolamprologus brichardi/pulcher (older radiation, Lake Tanganyika), Metriaclima zebra (recent radiation, Lake Malawi), Pundamilia nyererei (very recent radiation, Lake Victoria), and Astatotilapia burtoni (riverine species around Lake Tanganyika). We found an excess of gene duplications in the East African lineage compared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions, and regulation by novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-wide diversifying selection on coding and regulatory variants, some of which were recruited from ancient polymorphisms. We conclude that a number of molecular mechanisms shaped East African cichlid genomes, and that amassing of standing variation during periods of relaxed purifying selection may have been important in facilitating subsequent evolutionary diversification.


Assuntos
Ciclídeos/classificação , Ciclídeos/genética , Evolução Molecular , Especiação Genética , Genoma/genética , África Oriental , Animais , Elementos de DNA Transponíveis/genética , Duplicação Gênica/genética , Regulação da Expressão Gênica/genética , Genômica , Lagos , MicroRNAs/genética , Filogenia , Polimorfismo Genético/genética
8.
Nature ; 496(7445): 311-6, 2013 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-23598338

RESUMO

The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.


Assuntos
Evolução Biológica , Peixes/classificação , Peixes/genética , Genoma/genética , Animais , Animais Geneticamente Modificados , Embrião de Galinha , Sequência Conservada/genética , Elementos Facilitadores Genéticos/genética , Evolução Molecular , Extremidades/anatomia & histologia , Extremidades/crescimento & desenvolvimento , Peixes/anatomia & histologia , Peixes/fisiologia , Genes Homeobox/genética , Genômica , Imunoglobulina M/genética , Camundongos , Anotação de Sequência Molecular , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNA , Vertebrados/anatomia & histologia , Vertebrados/genética , Vertebrados/fisiologia
10.
J Exp Zool B Mol Dev Evol ; 340(8): 481-483, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-38031502
11.
Nature ; 484(7392): 55-61, 2012 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-22481358

RESUMO

Marine stickleback fish have colonized and adapted to thousands of streams and lakes formed since the last ice age, providing an exceptional opportunity to characterize genomic mechanisms underlying repeated ecological adaptation in nature. Here we develop a high-quality reference genome assembly for threespine sticklebacks. By sequencing the genomes of twenty additional individuals from a global set of marine and freshwater populations, we identify a genome-wide set of loci that are consistently associated with marine-freshwater divergence. Our results indicate that reuse of globally shared standing genetic variation, including chromosomal inversions, has an important role in repeated evolution of distinct marine and freshwater sticklebacks, and in the maintenance of divergent ecotypes during early stages of reproductive isolation. Both coding and regulatory changes occur in the set of loci underlying marine-freshwater evolution, but regulatory changes appear to predominate in this well known example of repeated adaptive evolution in nature.


Assuntos
Adaptação Fisiológica/genética , Evolução Biológica , Genoma/genética , Smegmamorpha/genética , Alaska , Animais , Organismos Aquáticos/genética , Inversão Cromossômica/genética , Cromossomos/genética , Sequência Conservada/genética , Ecótipo , Feminino , Água Doce , Variação Genética/genética , Genômica , Dados de Sequência Molecular , Água do Mar , Análise de Sequência de DNA
12.
BMC Genomics ; 18(1): 65, 2017 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-28073353

RESUMO

BACKGROUND: Although many algorithms are now available that aim to characterize different classes of structural variation, discovery of balanced rearrangements such as inversions remains an open problem. This is mainly due to the fact that breakpoints of such events typically lie within segmental duplications or common repeats, which reduces the mappability of short reads. The algorithms developed within the 1000 Genomes Project to identify inversions are limited to relatively short inversions, and there are currently no available algorithms to discover large inversions using high throughput sequencing technologies. RESULTS: Here we propose a novel algorithm, VALOR, to discover large inversions using new sequencing methods that provide long range information such as 10X Genomics linked-read sequencing, pooled clone sequencing, or other similar technologies that we commonly refer to as long range sequencing. We demonstrate the utility of VALOR using both pooled clone sequencing and 10X Genomics linked-read sequencing generated from the genome of an individual from the HapMap project (NA12878). We also provide a comprehensive comparison of VALOR against several state-of-the-art structural variation discovery algorithms that use whole genome shotgun sequencing data. CONCLUSIONS: In this paper, we show that VALOR is able to accurately discover all previously identified and experimentally validated large inversions in the same genome with a low false discovery rate. Using VALOR, we also predicted a novel inversion, which we validated using fluorescent in situ hybridization. VALOR is available at https://github.com/BilkentCompGen/VALOR.


Assuntos
Genômica/métodos , Inversão de Sequência/genética , Algoritmos , Genoma Humano/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Sequenciamento Completo do Genoma
13.
Mol Biol Evol ; 33(9): 2337-44, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27288344

RESUMO

The sea lamprey (Petromyzon marinus) is a basal vertebrate that undergoes developmentally programmed genome rearrangements (PGRs) during early development. These events facilitate the elimination of ∼20% of the genome from the somatic cell lineage, resulting in distinct somatic and germline genomes. Thus far only a handful of germline-specific genes have been definitively identified within the estimated 500 Mb of DNA that is deleted during PGR, although a few thousand germline-specific genes are thought to exist. To improve our understanding of the evolutionary/developmental logic of PGR, we generated computational predictions to identify candidate germline-specific genes within a new transcriptomic dataset derived from adult germline and the early embryonic stages during which PGR occurs. Follow-up validation studies identified 44 germline-specific genes and further characterized patterns of transcription and DNA loss during early embryogenesis. Expression analyses reveal that many of these genes are differentially expressed during early embryogenesis and presumably function in the early development of the germline. Ontology analyses indicate that many of these germline-specific genes play known roles in germline development, pluripotency, and oncogenesis (when misexpressed). These studies provide support for the theory that PGR serves to segregate molecular functions related to germline development/pluripotency in order to prevent their potential misexpression in somatic cells. This larger set of eliminated genes also allows us to extend the evolutionary/developmental breadth of this theory, as some deleted genes (or their gnathostome homologs) appear to be associated with the early development of somatic lineages, perhaps through the evolution of novel functions within gnathostome lineages.


Assuntos
Petromyzon/embriologia , Petromyzon/genética , Animais , DNA/sangue , DNA/genética , Desenvolvimento Embrionário/genética , Evolução Molecular , Genoma , Células Germinativas , Masculino , Petromyzon/sangue , Filogenia , Análise de Sequência de DNA
14.
Mol Biol Evol ; 33(12): 3033-3041, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27512111

RESUMO

Myoglobin is a respiratory protein that serves as a model system in a variety of biological fields. Its main function is to deliver and store O2 in the heart and skeletal muscles, but myoglobin is also instrumental in homeostasis of nitric oxide (NO) and detoxification of reactive oxygen species (ROS). Almost every vertebrate harbors a single myoglobin gene; only some cyprinid fishes have two recently duplicated myoglobin genes. Here we show that the West African lungfish Protopterus annectens has at least seven distinct myoglobin genes (PanMb1-7), which diverged early in the evolution of lungfish and showed an enhanced evolutionary rate. These myoglobins are lungfish specific, and no other globin gene was found amplified. The myoglobins are differentially expressed in various lungfish tissues, and the brain is the main site of myoglobin expression. The typical myoglobin-containing tissues, the skeletal muscle and the heart, have much lower myoglobin mRNA levels. Muscle and heart express distinct myoglobins (PanMb1 and PanMb3, respectively). In cell culture, lungfish myoglobins improved cellular survival under hypoxia albeit with different efficiencies and reduced the production of reactive oxygen species. Only Mb2 and Mb6 enhanced the energy status of the cells. The unexpected diversity of myoglobin hints to a functional diversification of this gene: some myoglobins may have adapted to the O2 requirements of the specific tissue and help the lungfish to survive hypoxic periods; other myoglobins may have taken over the roles of neuroglobin and cytoglobin, which appear to be missing in the West African lungfish.


Assuntos
Peixes/genética , Mioglobina/genética , Sequência de Aminoácidos , Animais , Evolução Biológica , Peixes/sangue , Peixes/metabolismo , Duplicação Gênica , Variação Genética , Músculo Esquelético/metabolismo , Mioglobina/metabolismo , Oxigênio/metabolismo , Filogenia , RNA Mensageiro/metabolismo , Vertebrados/genética
15.
J Exp Zool B Mol Dev Evol ; 328(1-2): 97-105, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27862964

RESUMO

The pelvic fins of male South American lungfish, Lepidosiren paradoxa, are adorned with a distinctive array of filaments, which grow and become highly vascularized during the breeding season. The resemblance between these pelvic fin filaments (PFFs) and external gills of other vertebrates suggested that this gill-like structure was used for physiological gas exchange. It has been proposed that the unique pelvic fin of male L. paradoxa is used for release of oxygen from its blood into the environment in order to aerate its nesting brood, or, conversely, as an auxiliary respiratory organ by absorbing oxygen from the environment into its bloodstream. Here, we employed histology, scanning electron microscopy (SEM) and quantitative PCR (qPCR) to assess whether the morphology and molecular profile of PFFs are compatible with a role in gas exchange. First, we closely examined its external morphology and showed that PFFs develop from short papillae during the rainy season, but remain covered by a thick nonvascularized epithelium. Histological examination confirmed that capillaries within the filaments are separated from the exterior by a basement membrane and a stratified epithelium composed of four to five cell layers. In addition, SEM analysis revealed significant differences between the fin filament epithelium and typical gill epithelium. Finally, our qPCR results showed that five genes commonly expressed in gills were downregulated in PFFs relative to their expression in regular pectoral fin epidermis. Collectively, our results do not directly support a role for PFFs, commonly referred to as "limb gills", in oxygen release or uptake.


Assuntos
Nadadeiras de Animais/anatomia & histologia , Nadadeiras de Animais/fisiologia , Peixes/anatomia & histologia , Peixes/fisiologia , Animais , Epitélio/ultraestrutura , Brânquias/ultraestrutura , Masculino , Reprodução , Fatores Sexuais
16.
BMC Genet ; 18(1): 19, 2017 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-28253860

RESUMO

BACKGROUND: Acipenseriformes is a basal lineage of ray-finned fishes and comprise 27 extant species of sturgeons and paddlefishes. They are characterized by several specific genomic features as broad ploidy variation, high chromosome numbers, presence of numerous microchromosomes and propensity to interspecific hybridization. The presumed palaeotetraploidy of the American paddlefish was recently validated by molecular phylogeny and Hox genes analyses. A whole genome duplication in the paddlefish lineage was estimated at approximately 42 Mya and was found to be independent from several genome duplications evidenced in its sister lineage, i.e. sturgeons. We tested the ploidy status of available chromosomal markers after the expected rediploidization. Further we tested, whether paralogs of Hox gene clusters originated from this paddlefish specific genome duplication are cytogenetically distinguishable. RESULTS: We found that both paralogs HoxA alpha and beta were distinguishable without any overlapping of the hybridization signal - each on one pair of large metacentric chromosomes. Of the HoxD, only the beta paralog was unequivocally identified, whereas the alpha paralog did not work and yielded only an inconclusive diffuse signal. Chromosomal markers on three diverse ploidy levels reflecting different stages of rediploidization were identified: quadruplets retaining their ancestral tetraploid condition, semi-quadruplets still reflecting the ancestral tetraploidy with clear signs of advanced rediploidization, doublets were diploidized with ancestral tetraploidy already blurred. Also some of the available microsatellite data exhibited diploid allelic band patterns at their loci whereas another locus showed more than two alleles. CONCLUSIONS: Our exhaustive staining of paddlefish chromosomes combined with cytogenetic mapping of ribosomal genes and Hox paralogs and with microsatellite data, brings a closer look at results of the process of rediploidization in the course of paddlefish genome evolution. We show a partial rediploidization represented by a complex mosaic structure comparable with segmental paleotetraploidy revealed in sturgeons (Acipenseridae). Sturgeons and paddlefishes with their high propensity for whole genome duplication thus offer suitable animal model systems to further explore evolutionary processes that were shaping the early evolution of all vertebrates.


Assuntos
Diploide , Proteínas de Peixes/genética , Peixes/genética , Duplicação Gênica , Genômica , Hibridização in Situ Fluorescente , Homologia de Sequência do Ácido Nucleico , Animais , Técnicas de Genotipagem , Repetições de Microssatélites/genética , Ribossomos/genética
17.
J Exp Biol ; 220(Pt 7): 1197-1201, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28137975

RESUMO

We have developed an efficient method for the preparation and maintenance of primary cell cultures isolated from adult Mnemiopsis leidyi, a lobate ctenophore. Our primary cell cultures are derived from tissue explants or enzymatically dissociated cells, and maintained in a complex undefined ctenophore mesogleal serum. These methods can be used to isolate, maintain and visually monitor ctenophore cells to assess proliferation, cellular morphology and cell differentiation in future studies. Exemplar cell types that can be easily isolated from primary cultures include proliferative ectodermal and endodermal cells, motile amebocyte-like cells, and giant smooth muscle cells that exhibit inducible contractile properties. We have also derived 'tissue envelopes' containing sections of endodermal canal surrounded by mesoglea and ectoderm that can be used to monitor targeted cell types in an in vivo context. Access to efficient and reliably generated primary cell cultures will facilitate the analysis of ctenophore development, physiology and morphology from a cell biological perspective.


Assuntos
Ctenóforos/citologia , Cultura Primária de Células/métodos , Animais , Células Cultivadas , Dissecação , Corantes Fluorescentes/análise , Imagem Óptica
19.
PLoS Genet ; 8(2): e1002483, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22359511

RESUMO

Devil facial tumour disease (DFTD) is a fatal, transmissible malignancy that threatens the world's largest marsupial carnivore, the Tasmanian devil, with extinction. First recognised in 1996, DFTD has had a catastrophic effect on wild devil numbers, and intense research efforts to understand and contain the disease have since demonstrated that the tumour is a clonal cell line transmitted by allograft. We used chromosome painting and gene mapping to deconstruct the DFTD karyotype and determine the chromosome and gene rearrangements involved in carcinogenesis. Chromosome painting on three different DFTD tumour strains determined the origins of marker chromosomes and provided a general overview of the rearrangement in DFTD karyotypes. Mapping of 105 BAC clones by fluorescence in situ hybridisation provided a finer level of resolution of genome rearrangements in DFTD strains. Our findings demonstrate that only limited regions of the genome, mainly chromosomes 1 and X, are rearranged in DFTD. Regions rearranged in DFTD are also highly rearranged between different marsupials. Differences between strains are limited, reflecting the unusually stable nature of DFTD. Finally, our detailed maps of both the devil and tumour karyotypes provide a physical framework for future genomic investigations into DFTD.


Assuntos
Mapeamento Cromossômico , Neoplasias Faciais/veterinária , Genoma , Marsupiais/genética , Doenças dos Animais/genética , Doenças dos Animais/transmissão , Animais , Coloração Cromossômica , Células Clonais , Neoplasias Faciais/genética , Rearranjo Gênico , Cariotipagem , Transplante de Neoplasias , Especificidade da Espécie
20.
J Exp Zool B Mol Dev Evol ; 322(6): 390-402, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25243252

RESUMO

The coelacanth is the basal-most extant sarcopterygian that has teeth and tooth-like structures, comprising bone, dentin, and enamel or enameloid. Formation of these tissues involves many members of the secretory calcium-binding protein (SCPP) family. In tetrapods, acidic-residue-rich SCPPs are used in mineralization of bone and dentin, whereas Pro/Gln-rich SCPPs participate in enamel formation. Teleosts also employ many SCPPs for tissue mineralization. Nevertheless, the repertoire of SCPPs is largely different in teleosts and tetrapods; hence, filling this gap would be critical to elucidate early evolution of mineralized tissues in osteichthyans. In the present study, we searched for SCPP genes in the coelacanth genome and identified 11, of which two have clear orthologs in both tetrapods and teleosts, seven only in tetrapods, and two in neither of them. Given the divergence times of these vertebrate lineages, our discovery of this many SCPP genes shared between the coelacanth and tetrapods, but not with teleosts, suggests a complicated evolutionary scheme of SCPP genes in early osteichthyans. Our investigation also revealed both conserved and derived characteristics of SCPPs in the coelacanth and other vertebrates. Notably, acidic SCPPs independently evolved various acidic repeats in different lineages, while maintaining high acidity, presumably important for interactions with calcium. Furthermore, the three Pro/Gln-rich SCPP genes, required for mineralizing enamel matrix and confirmed only in tetrapods, were all identified in the coelacanth, strongly suggesting that enamel is equivalent in the coelacanth and tetrapods. This finding corroborates the previous proposition that true enamel evolved much earlier than the origin of tetrapods.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Evolução Molecular , Peixes/genética , Amelogênese/genética , Animais , Evolução Biológica , Calcificação Fisiológica/genética , Proteínas do Esmalte Dentário/genética , Dentina/química , Filogenia , Calcificação de Dente/genética , Vertebrados/genética
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