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1.
Dev Biol ; 482: 34-43, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34902310

RESUMO

The DAN gene family (DAN, Differential screening-selected gene Aberrant in Neuroblastoma) is a group of genes that is expressed during development and plays fundamental roles in limb bud formation and digitation, kidney formation and morphogenesis and left-right axis specification. During adulthood the expression of these genes are associated with diseases, including cancer. Although most of the attention to this group of genes has been dedicated to understanding its role in physiology and development, its evolutionary history remains poorly understood. Thus, the goal of this study is to investigate the evolutionary history of the DAN gene family in vertebrates, with the objective of complementing the already abundant physiological information with an evolutionary context. Our results recovered the monophyly of all DAN gene family members and divide them into five main groups. In addition to the well-known DAN genes, our phylogenetic results revealed the presence of two new DAN gene lineages; one is only retained in cephalochordates, whereas the other one (GREM3) was only identified in cartilaginous fish, holostean fish, and coelacanth. According to the phyletic distribution of the genes, the ancestor of gnathostomes possessed a repertoire of eight DAN genes, and during the radiation of the group GREM1, GREM2, SOST, SOSTDC1, and NBL1 were retained in all major groups, whereas, GREM3, CER1, and DAND5 were differentially lost.


Assuntos
Sequência de Bases/genética , Proteínas de Ciclo Celular/genética , Sequência Conservada/genética , Desenvolvimento Embrionário/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Anfíbios , Animais , Aves , Padronização Corporal/genética , Citocinas/genética , Evolução Molecular , Peixes , Peptídeos e Proteínas de Sinalização Intercelular/genética , Botões de Extremidades/crescimento & desenvolvimento , Mamíferos , Morfogênese/genética , Répteis
2.
RNA ; 28(4): 609-621, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35064043

RESUMO

Transposable elements (TEs) are genomic parasites that can propagate throughout host genomes. Mammalian genomes are typically dominated by LINE retrotransposons and their associated SINEs, and germline mobilization is a challenge to genome integrity. There are defenses against TE proliferation and the PIWI/piRNA defense is among the most well understood. However, the PIWI/piRNA system has been investigated largely in animals with actively mobilizing TEs and it is unclear how the PIWI/piRNA system functions in the absence of mobilizing TEs. The 13-lined ground squirrel provides the opportunity to examine PIWI/piRNA and TE dynamics within the context of minimal, and possibly nonexistent, TE accumulation. To do so, we compared the PIWI/piRNA dynamics in squirrels to observations from the rabbit and mouse. Despite a lack of young insertions in squirrels, TEs were still actively transcribed at higher levels compared to mouse and rabbit. All three Piwi genes were not expressed, prior to P8 in squirrel testis, and there was little TE expression change with the onset of Piwi expression. We also demonstrated there was not a major expression change in the young squirrel LINE families in the transition from juvenile to adult testis in contrast to young mouse and rabbit LINE families. These observations lead us to conclude that PIWI suppression, was weaker for squirrel LINEs and SINEs and did not strongly reduce their transcription. We speculate that, although the PIWI/piRNA system is adaptable to novel TE threats, transcripts from TEs that are no longer threatening receive less attention from PIWI proteins.


Assuntos
Elementos de DNA Transponíveis , Roedores , Animais , Elementos de DNA Transponíveis/genética , Células Germinativas/metabolismo , Humanos , Masculino , Camundongos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Coelhos , Roedores/genética , Roedores/metabolismo , Testículo/metabolismo
3.
Genome Biol Evol ; 13(10)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34480557

RESUMO

Globin-X (GbX) is an enigmatic member of the vertebrate globin gene family with a wide phyletic distribution that spans protostomes and deuterostomes. Unlike canonical globins such as hemoglobins and myoglobins, functional data suggest that GbX does not have a primary respiratory function. Instead, evidence suggests that the monomeric, membrane-bound GbX may play a role in cellular signaling or protection against the oxidation of membrane lipids. Recently released genomes from key vertebrates provide an excellent opportunity to address questions about the early stages of the evolution of GbX in vertebrates. We integrate bioinformatics, synteny, and phylogenetic analyses to characterize the diversity of GbX genes in nonteleost ray-finned fishes, resolve relationships between the GbX genes of cartilaginous fish and bony vertebrates, and demonstrate that the GbX genes of cyclostomes and gnathostomes derive from independent duplications. Our study highlights the role that whole-genome duplications (WGDs) have played in expanding the repertoire of genes in vertebrate genomes. Our results indicate that GbX paralogs have a remarkably high rate of retention following WGDs relative to other globin genes and provide an evolutionary framework for interpreting results of experiments that examine functional properties of GbX and patterns of tissue-specific expression. By identifying GbX paralogs that are products of different WGDs, our results can guide the design of experimental work to explore whether gene duplicates that originate via WGDs have evolved novel functional properties or expression profiles relative to singleton or tandemly duplicated copies of GbX.


Assuntos
Evolução Molecular , Duplicação Gênica , Animais , Hemoglobinas/genética , Filogenia , Vertebrados/genética
4.
Mycologia ; 113(5): 938-948, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133260

RESUMO

The genus Gaeumannomyces (Magnaporthaceae, Magnaporthales, Sordariomycetes, Ascomycota) includes root-infecting pathogens, saprobes, and endophytes. Morphological, biological, and phylogenetic analyses were employed to identify fungal isolates derived from turfgrass roots colonized with ectotrophic, dark runner hyphae. Phylogenetic trees for partial sequences of the 18S nuc rDNA, ITS1-5.8S-ITS2 nuc rDNA internal transcribed spacer, and 28S nuc rDNA regions and of the minichromosome maintenance complex 7 (MCM7), largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-alpha (TEF1) genes were obtained via maximum likelihood and Bayesian methods. Our isolates consistently formed a distinct and highly supported clade within Gaeumannomyces. Common and distinctive biological and morphological characters reinforced these findings. Additionally, we conducted pathogenicity evaluations and demonstrated the ability of this fungus to colonize roots of ultradwarf bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davey), its native host, via ectotrophic, dark runner hyphae, causing disease symptoms including root discoloration and reduced root and shoot mass. Altogether, our discoveries enabled recognition and description of a new species, Gaeumannomyces nanograminis, associated with rotted roots of ultradwarf bermudagrass.


Assuntos
Ascomicetos , Cynodon , Ascomicetos/genética , Teorema de Bayes , DNA Fúngico/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Filogenia , Análise de Sequência de DNA , Estados Unidos
5.
Proc Natl Acad Sci U S A ; 118(13)2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33753505

RESUMO

Dive capacities of air-breathing vertebrates are dictated by onboard O2 stores, suggesting that physiologic specialization of diving birds such as penguins may have involved adaptive changes in convective O2 transport. It has been hypothesized that increased hemoglobin (Hb)-O2 affinity improves pulmonary O2 extraction and enhances the capacity for breath-hold diving. To investigate evolved changes in Hb function associated with the aquatic specialization of penguins, we integrated comparative measurements of whole-blood and purified native Hb with protein engineering experiments based on site-directed mutagenesis. We reconstructed and resurrected ancestral Hb representing the common ancestor of penguins and the more ancient ancestor shared by penguins and their closest nondiving relatives (order Procellariiformes, which includes albatrosses, shearwaters, petrels, and storm petrels). These two ancestors bracket the phylogenetic interval in which penguin-specific changes in Hb function would have evolved. The experiments revealed that penguins evolved a derived increase in Hb-O2 affinity and a greatly augmented Bohr effect (i.e., reduced Hb-O2 affinity at low pH). Although an increased Hb-O2 affinity reduces the gradient for O2 diffusion from systemic capillaries to metabolizing cells, this can be compensated by a concomitant enhancement of the Bohr effect, thereby promoting O2 unloading in acidified tissues. We suggest that the evolved increase in Hb-O2 affinity in combination with the augmented Bohr effect maximizes both O2 extraction from the lungs and O2 unloading from the blood, allowing penguins to fully utilize their onboard O2 stores and maximize underwater foraging time.


Assuntos
Adaptação Fisiológica , Oxigênio/metabolismo , Oxiemoglobinas/metabolismo , Spheniscidae/fisiologia , Substituição de Aminoácidos , Animais , Oxiemoglobinas/química , Oxiemoglobinas/genética , Filogenia , Conformação Proteica , Engenharia de Proteínas , Spheniscidae/sangue , Spheniscidae/classificação
6.
Front Genet ; 11: 858, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922435

RESUMO

Globins are small heme-proteins that reversibly bind oxygen. Their most prominent roles in vertebrates are the transport and storage of O2 for oxidative energy metabolism, but recent research has suggested alternative, non-respiratory globin functions. In the species-rich and ecologically highly diverse taxon of arthropods, the copper-containing hemocyanin is considered the main respiratory protein. However, recent studies have suggested the presence of globin genes and their proteins in arthropod taxa, including model species like Drosophila. To systematically assess the taxonomic distribution, evolution and diversity of globins in arthropods, we systematically searched transcriptome and genome sequence data and found a conserved, widespread occurrence of three globin classes in arthropods: hemoglobin-like (HbL), globin X (GbX), and globin X-like (GbXL) protein lineages. These globin types were previously identified in protostome and deuterostome animals including vertebrates, suggesting their early ancestry in Metazoa. The HbL genes show multiple, lineage-specific gene duplications in all major arthropod clades. Some HbL genes (e.g., Glob2 and 3 of Drosophila) display particularly fast substitution rates, possibly indicating the evolution of novel functions, e.g., in spermatogenesis. In contrast, arthropod GbX and GbXL globin genes show high evolutionary stability: GbXL is represented by a single-copy gene in all arthropod groups except Brachycera, and representatives of the GbX clade are present in all examined taxa except holometabolan insects. GbX and GbXL both show a brain-specific expression. Most arthropod GbX and GbXL proteins, but also some HbL variants, include sequence motifs indicative of potential N-terminal acylation (i.e., N-myristoylation, 3C-palmitoylation). All arthropods except for the brachyceran Diptera harbor at least one such potentially acylated globin copy, confirming the hypothesis of an essential, conserved globin function associated with the cell membrane. In contrast to other animals, the fourth ancient globin lineage, represented by neuroglobin, appears to be absent in arthropods, and the putative arthropod orthologs of the fifth metazoan globin lineage, androglobin, lack a recognizable globin domain. Thus, the remarkable evolutionary stability of some globin variants is contrasted by occasional dynamic gene multiplication or even loss of otherwise strongly conserved globin lineages in arthropod phylogeny.

7.
Am J Physiol Regul Integr Comp Physiol ; 318(3): R657-R667, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32022587

RESUMO

Hemoglobins (Hbs) of crocodilians are reportedly characterized by unique mechanisms of allosteric regulatory control, but there are conflicting reports regarding the importance of different effectors, such as chloride ions, organic phosphates, and CO2. Progress in understanding the unusual properties of crocodilian Hbs has also been hindered by a dearth of structural information. Here, we present the first comparative analysis of blood properties and Hb structure and function in a phylogenetically diverse set of crocodilian species. We examine mechanisms of allosteric regulation in the Hbs of 13 crocodilian species belonging to the families Crocodylidae and Alligatoridae. We also report new amino acid sequences for the α- and ß-globins of these taxa, which, in combination with structural analyses, provide insights into molecular mechanisms of allosteric regulation. All crocodilian Hbs exhibited a remarkably strong sensitivity to CO2, which would permit effective O2 unloading to tissues in response to an increase in metabolism during intense activity and diving. Although the Hbs of all crocodilians exhibit similar intrinsic O2-affinities, there is considerable variation in sensitivity to Cl- ions and ATP, which appears to be at least partly attributable to variation in the extent of NH2-terminal acetylation. Whereas chloride appears to be a potent allosteric effector of all crocodile Hbs, ATP has a strong, chloride-independent effect on Hb-O2 affinity only in caimans. Modeling suggests that allosteric ATP binding has a somewhat different structural basis in crocodilian and mammalian Hbs.


Assuntos
Trifosfato de Adenosina/metabolismo , Regulação Alostérica/fisiologia , Dióxido de Carbono/metabolismo , Cloretos/metabolismo , Hemoglobinas/metabolismo , Oxigênio/sangue , Sequência de Aminoácidos/fisiologia , Animais , Temperatura
8.
Mycologia ; 112(1): 52-63, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31846602

RESUMO

The genus Magnaporthiopsis of Magnaporthaceae (Magnaporthales, Sordariomycetes, Ascomycota) contains species that are predominantly necrotrophic pathogens, often producing simple hyphopodia and dark, ectotrophic runner hyphae on plant roots and stems during colonization. Fungal isolates from turfgrass roots with dark and ectotrophic runner hyphae were examined and identified based on morphological, biological, and phylogenetic analyses. Maximum likelihood and Bayesian methods were implemented to obtain phylogenetic trees for partial sequences of the 18S nuc rDNA, ITS1-5.8S-ITS2 nuc rDNA internal transcribed spacer, and 28S nuc rDNA regions, and of the minichromosome maintenance complex 7 (MCM7), largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-alpha (TEF1) genes. Our isolates consistently formed a distinct and highly supported clade within Magnaporthiopsis. These findings were reinforced by common and distinctive biological and morphological characters. Additionally, we conducted pathogenicity evaluations and demonstrated the ability of this fungus to colonize roots of ultradwarf bermudagrass, one of its native hosts, via ectotrophic, dark runner hyphae, causing disease symptoms including root discoloration and reduced root and shoot mass. Altogether, our discoveries enabled recognition and description of a new species, Magnaporthiopsis cynodontis, which has widespread distribution in the United States.


Assuntos
Ascomicetos/classificação , Ascomicetos/patogenicidade , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Ascomicetos/citologia , Ascomicetos/fisiologia , DNA Fúngico/genética , DNA Ribossômico/genética , Proteínas Fúngicas/genética , Hifas/classificação , Hifas/citologia , Hifas/patogenicidade , Hifas/fisiologia , Filogenia , Raízes de Plantas/microbiologia , RNA Ribossômico/genética , Análise de Sequência de DNA , Estados Unidos
9.
J Exp Biol ; 223(Pt 2)2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31836650

RESUMO

Among the numerous lineages of teleost fish that have independently transitioned from obligate water breathing to facultative air breathing, evolved properties of hemoglobin (Hb)-O2 transport may have been shaped by the prevalence and severity of aquatic hypoxia (which influences the extent to which fish are compelled to switch to aerial respiration) as well as the anatomical design of air-breathing structures and the cardiovascular system. Here, we examined the structure and function of Hbs in an amphibious, facultative air-breathing fish, the blue-spotted mudskipper (Boleophthalmus pectinirostris). We also characterized the genomic organization of the globin gene clusters of the species and we integrated phylogenetic and comparative genomic analyses to unravel the duplicative history of the genes that encode the subunits of structurally distinct mudskipper Hb isoforms (isoHbs). The B. pectinirostris isoHbs exhibit high intrinsic O2 affinities, similar to those of hypoxia-tolerant, water-breathing teleosts, and remarkably large Bohr effects. Genomic analysis of conserved synteny revealed that the genes that encode the α-type subunits of the two main adult isoHbs are members of paralogous gene clusters that represent products of the teleost-specific whole-genome duplication. Experiments revealed no appreciable difference in the oxygenation properties of co-expressed isoHbs in spite of extensive amino acid divergence between the alternative α-chain subunit isoforms. It therefore appears that the ability to switch between aquatic and aerial respiration does not necessarily require a division of labor between functionally distinct isoHbs with specialized oxygenation properties.


Assuntos
Evolução Molecular , Peixes/fisiologia , Hemoglobinas/química , Respiração , Animais , Isoformas de Proteínas/química
10.
Evol Dev ; 21(4): 205-217, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31210006

RESUMO

Nodal is a signaling molecule that belongs to the transforming growth factor-ß superfamily that plays key roles during the early stages of development of animals. In vertebrates Nodal forms an heterodimer with a GDF1/3 protein to activate the Nodal pathway. Vertebrates have a paralog of nodal in their genomes labeled Nodal-related, but the evolutionary history of these genes is a matter of debate, mainly because of the presence of a variable numbers of genes in the vertebrate genomes sequenced so far. Thus, the goal of this study was to investigate the evolutionary history of the Nodal and Nodal-related genes with an emphasis in tracking changes in the number of genes among vertebrates. Our results show the presence of two gene lineages (Nodal and Nodal-related) that can be traced back to the ancestor of jawed vertebrates. These lineages have undergone processes of differential retention and lineage-specific expansions. Our results imply that Nodal and Nodal-related duplicated at the latest in the ancestor of gnathostomes, and they still retain a significant level of functional redundancy. By comparing the evolution of the Nodal/Nodal-related with GDF1/3 gene family, it is possible to infer that there are several types of heterodimers that can trigger the Nodal pathway among vertebrates.


Assuntos
Evolução Molecular , Proteína Nodal/genética , Proteína Nodal/metabolismo , Transdução de Sinais/fisiologia , Vertebrados/genética , Vertebrados/fisiologia , Animais , Biologia Computacional , Regulação da Expressão Gênica , Filogenia
11.
Genome Biol Evol ; 10(8): 2110-2129, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30060036

RESUMO

Colubridae represents the most phenotypically diverse and speciose family of snakes, yet no well-assembled and annotated genome exists for this lineage. Here, we report and analyze the genome of the garter snake, Thamnophis sirtalis, a colubrid snake that is an important model species for research in evolutionary biology, physiology, genomics, behavior, and the evolution of toxin resistance. Using the garter snake genome, we show how snakes have evolved numerous adaptations for sensing and securing prey, and identify features of snake genome structure that provide insight into the evolution of amniote genomes. Analyses of the garter snake and other squamate reptile genomes highlight shifts in repeat element abundance and expansion within snakes, uncover evidence of genes under positive selection, and provide revised neutral substitution rate estimates for squamates. Our identification of Z and W sex chromosome-specific scaffolds provides evidence for multiple origins of sex chromosome systems in snakes and demonstrates the value of this genome for studying sex chromosome evolution. Analysis of gene duplication and loss in visual and olfactory gene families supports a dim-light ancestral condition in snakes and indicates that olfactory receptor repertoires underwent an expansion early in snake evolution. Additionally, we provide some of the first links between secreted venom proteins, the genes that encode them, and their evolutionary origins in a rear-fanged colubrid snake, together with new genomic insight into the coevolutionary arms race between garter snakes and highly toxic newt prey that led to toxin resistance in garter snakes.


Assuntos
Evolução Molecular , Genoma , Anotação de Sequência Molecular , Comportamento Predatório , Serpentes/genética , Adaptação Fisiológica , Animais , Feminino , Células Fotorreceptoras de Vertebrados , Receptores Odorantes/genética , Répteis/classificação , Répteis/genética , Pigmentos da Retina/genética , Seleção Genética , Serpentes/classificação , Serpentes/fisiologia , Peçonhas/genética , Canais de Sódio Disparados por Voltagem/genética
12.
Proc Natl Acad Sci U S A ; 115(8): 1865-1870, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29432191

RESUMO

When different species experience similar selection pressures, the probability of evolving similar adaptive solutions may be influenced by legacies of evolutionary history, such as lineage-specific changes in genetic background. Here we test for adaptive convergence in hemoglobin (Hb) function among high-altitude passerine birds that are native to the Qinghai-Tibet Plateau, and we examine whether convergent increases in Hb-O2 affinity have a similar molecular basis in different species. We documented that high-altitude parid and aegithalid species from the Qinghai-Tibet Plateau have evolved derived increases in Hb-O2 affinity in comparison with their closest lowland relatives in East Asia. However, convergent increases in Hb-O2 affinity and convergence in underlying functional mechanisms were seldom attributable to the same amino acid substitutions in different species. Using ancestral protein resurrection and site-directed mutagenesis, we experimentally confirmed two cases in which parallel substitutions contributed to convergent increases in Hb-O2 affinity in codistributed high-altitude species. In one case involving the ground tit (Parus humilis) and gray-crested tit (Lophophanes dichrous), parallel amino acid replacements with affinity-enhancing effects were attributable to nonsynonymous substitutions at a CpG dinucleotide, suggesting a possible role for mutation bias in promoting recurrent changes at the same site. Overall, most altitude-related changes in Hb function were caused by divergent amino acid substitutions, and a select few were caused by parallel substitutions that produced similar phenotypic effects on the divergent genetic backgrounds of different species.


Assuntos
Adaptação Fisiológica/genética , Altitude , Hemoglobinas/fisiologia , Passeriformes/genética , Passeriformes/fisiologia , Distribuição Animal , Animais , Evolução Molecular , Hemoglobinas/genética , Modelos Moleculares , Passeriformes/sangue , Conformação Proteica , Isoformas de Proteínas , Tibet
14.
Genome Biol Evol ; 10(1): 344-358, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29340581

RESUMO

The genes that encode the α- and ß-chain subunits of vertebrate hemoglobin have served as a model system for elucidating general principles of gene family evolution, but little is known about patterns of evolution in amniotes other than mammals and birds. Here, we report a comparative genomic analysis of the α- and ß-globin gene clusters in sauropsids (archosaurs and nonavian reptiles). The objectives were to characterize changes in the size and membership composition of the α- and ß-globin gene families within and among the major sauropsid lineages, to reconstruct the evolutionary history of the sauropsid α- and ß-globin genes, to resolve orthologous relationships, and to reconstruct evolutionary changes in the developmental regulation of gene expression. Our comparisons revealed contrasting patterns of evolution in the unlinked α- and ß-globin gene clusters. In the α-globin gene cluster, which has remained in the ancestral chromosomal location, evolutionary changes in gene content are attributable to the differential retention of paralogous gene copies that were present in the common ancestor of tetrapods. In the ß-globin gene cluster, which was translocated to a new chromosomal location, evolutionary changes in gene content are attributable to differential gene gains (via lineage-specific duplication events) and gene losses (via lineage-specific deletions and inactivations). Consequently, all major groups of amniotes possess unique repertoires of embryonic and postnatally expressed ß-type globin genes that diversified independently in each lineage. These independently derived ß-type globins descend from a pair of tandemly linked paralogs in the most recent common ancestor of sauropsids.


Assuntos
Evolução Molecular , Família Multigênica , Filogenia , alfa-Globinas/genética , Globinas beta/genética , Animais , Duplicação Gênica , Genoma , Répteis/genética , Vertebrados/genética
15.
Gene ; 628: 275-280, 2017 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-28735726

RESUMO

Tuco-tucos (Ctenomys) and related coruros (Spalacopus) are South American subterranean rodents. An energetically demanding lifestyle within the hypoxic/hypercapnic underground atmosphere may change the selective regime on genes involved in O2 transport in blood. In addition, some species of tuco-tucos may be found at high altitude, thus facing additional reductions in changes O2 availabily. We examined sequence variation in the alpha globin subunit gene of hemoglobine in these lineages, within a robust phylogenetic context. Using different approaches (classical and Bayesian maximum likelihood (PAML/Datamonkey) and alternatives methods (TreeSAAP)) we found at least 2 sites with evidence of positive selection in the basal branch of Octodontidae, but not in tuco-tucos. These results suggest some adaptive changes associated to fossoriality, but not strictly to life underground.


Assuntos
Adaptação Biológica/genética , Variação Genética , Roedores/genética , alfa-Globinas/genética , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Evolução Molecular , Ordem dos Genes , Mutação , Filogenia , Roedores/classificação , Seleção Genética
16.
Gen Comp Endocrinol ; 252: 12-17, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28733228

RESUMO

The relaxin/insulin-like (RLN/INSL) gene family is a group of genes that encode peptide hormones involved in a variety of physiological functions related to reproduction. Previous studies have shown that relaxin plays a key role in widening of the pubic bone during labor and in gamete maturation. Because of these functions, studying the evolution of RLN1, the gene encoding for relaxin, is relevant in livestock species, most of which belong in the group Laurasiatheria, which includes cow, pig, horse, goat, and sheep in addition to bats, cetaceans and carnivores. Experimental evidence suggests that cows do not synthesize relaxin, but respond to it, and sheep apparently have a truncated RLN1 gene. Thus, we made use of genome sequence data to characterize the genomic locus of the RLN1 gene in Laurasiatherian mammals to better understand how cows lost the ability to synthesize this peptide. We found that all ruminants in our study (cow, giraffe, goat, sheep and Tibetan antelope) lack a functional RLN1 gene, and document the progressive loss of RLN1 in the lineage leading to cows. Our analyses indicate that 1 - all ruminants have lost all key regulatory elements upstream of the first exon, 2 - giraffe, goat, sheep and Tibetan antelope have multiple inactivating mutations in the RLN1 pseudogene, and 3 - the cow genome has lost all traces of RLN1. The 5' regulatory sequence plays a key role in activating expression, and the loss of this sequence would impair synthesis of mRNA. Our results suggest that changes in regulatory sequence preceded mutations in coding sequence and highlight the importance of these regions in maintaining proper gene function. In addition, we found that all bovids examined posses copies of the relaxin receptors, which explains why they are able to respond to relaxin despite their inability to produce it.


Assuntos
Bovinos/genética , Relaxina/genética , Animais , Sequência de Bases , Biologia Computacional , Genoma , Funções Verossimilhança , Filogenia , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , Relaxina/metabolismo
17.
Gen Comp Endocrinol ; 240: 129-137, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27769631

RESUMO

The study of the evolutionary history of genes related to human disease lies at the interface of evolution and medicine. These studies provide the evolutionary context on which medical researchers should work, and are also useful in providing information to suggest further genetic experiments, especially in model species where genetic manipulations can be made. Here we studied the evolution of the ß-adrenoreceptor gene family in vertebrates with the aim of adding an evolutionary framework to the already abundant physiological information. Our results show that in addition to the three already described vertebrate ß-adrenoreceptor genes there is an additional group containing cyclostome sequences. We suggest that ß-adrenoreceptors diversified as a product of the two whole genome duplications that occurred in the ancestor of vertebrates. Gene expression patterns are in general consistent across species, suggesting that expression dynamics were established early in the evolutionary history of vertebrates, and have been maintained since then. Finally, amino acid polymorphisms that are associated to pathological conditions in humans appear to be common in non-human mammals, suggesting that the phenotypic effects of these mutations depend on epistatic interaction with other positions. The evolutionary analysis of the ß-adrenoreceptors delivers new insights about the diversity of these receptors in vertebrates, the evolution of the expression patterns and a comparative perspective regarding the polymorphisms that in humans are linked to pathological conditions.


Assuntos
Evolução Molecular , Receptores Adrenérgicos beta/genética , Vertebrados/genética , Animais , Duplicação Gênica , Genoma , Humanos , Filogenia
18.
Science ; 354(6310): 336-339, 2016 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-27846568

RESUMO

To investigate the predictability of genetic adaptation, we examined the molecular basis of convergence in hemoglobin function in comparisons involving 56 avian taxa that have contrasting altitudinal range limits. Convergent increases in hemoglobin-oxygen affinity were pervasive among high-altitude taxa, but few such changes were attributable to parallel amino acid substitutions at key residues. Thus, predictable changes in biochemical phenotype do not have a predictable molecular basis. Experiments involving resurrected ancestral proteins revealed that historical substitutions have context-dependent effects, indicating that possible adaptive solutions are contingent on prior history. Mutations that produce an adaptive change in one species may represent precluded possibilities in other species because of differences in genetic background.


Assuntos
Adaptação Fisiológica/genética , Aves/genética , Evolução Molecular , Hemoglobina A/química , Hemoglobina A/genética , Hemoglobinas/química , Hemoglobinas/genética , Oxigênio/química , Substituição de Aminoácidos/genética , Animais , Aves/fisiologia , Hemoglobina A/classificação , Hemoglobinas/classificação , Mutação , Filogenia , Especificidade da Espécie
19.
Mycologia ; 108(5): 915-924, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27549619

RESUMO

A novel species of Curvularia was identified as a foliar pathogen of Cynodon dactylon (bermudagrass) and Zoysia matrella (zoysiagrass), two important warm-season turfgrasses in the southeastern United States. Field symptoms were conspicuous chocolate brown to black spots in turf of both species on golf course putting greens and fairways. Leaves of plants within these spots exhibited prominent, black eyespot lesions from which a darkly pigmented fungus was consistently isolated. The fungus produced gray- to black-olivaceous mycelium within 10 d on potato dextrose agar at 25 C but never produced conidia despite numerous attempts to induce them. Field symptoms were reproduced in inoculated plants of both grasses, and re-isolation of the pathogen from symptomatic tissues confirmed its pathogenicity in fulfillment of Koch's postulates. A phylogenetic analysis was performed using sequence markers of internal nuclear ribosomal transcribed spacer region (ITS), glyceralde-hyde-3-phosphate dehydrogenase (GPD1) and translation elongation factor 1-α (TEF 1). The concatenated phylogenetic tree showed strong support for a new species within Curvularia that is distinctly divergent from other Curvularia spp. Therefore, the darkly pigmented pathogen of warm-season turfgrasses is described and illustrated as a new species, Curvularia malina.


Assuntos
Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Análise por Conglomerados , Meios de Cultura , DNA Fúngico/química , DNA Fúngico/genética , DNA Intergênico/química , DNA Intergênico/genética , Glicerol-3-Fosfato Desidrogenase (NAD+)/genética , Técnicas Microbiológicas , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Pigmentos Biológicos/análise , Folhas de Planta/microbiologia , Análise de Sequência de DNA , Sudeste dos Estados Unidos
20.
Gene ; 591(1): 245-254, 2016 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-27432065

RESUMO

Genes related to human diseases should be natural targets for evolutionary studies, since they could provide clues regarding the genetic bases of pathologies and potential treatments. Here we studied the evolution of the reprimo gene family, a group of tumor-suppressor genes that are implicated in p53-mediated cell cycle arrest. These genes, especially the reprimo duplicate located on human chromosome 2, have been associated with epigenetic modifications correlated with transcriptional silencing and cancer progression. We demonstrate the presence of a third reprimo lineage that, together with the reprimo and reprimo-like genes, appears to have been differentially retained during the evolutionary history of vertebrates. We present evidence that these reprimo lineages originated early in vertebrate evolution and expanded as a result of the two rounds of whole genome duplications that occurred in the last common ancestor of vertebrates. The reprimo gene has been lost in birds, and the third reprimo gene lineage has been retained in only a few distantly related species, such as coelacanth and gar. Expression analyses revealed that the reprimo paralogs are mainly expressed in the nervous system. Different vertebrate lineages have retained different reprimo paralogs, and even in species that have retained multiple copies, only one of them is heavily expressed.


Assuntos
Proteínas de Ciclo Celular/genética , Evolução Molecular , Genes Supressores de Tumor , Família Multigênica , Filogenia , Vertebrados/genética , Sequência de Aminoácidos , Animais , Duplicação Gênica , Humanos , Funções Verossimilhança , Alinhamento de Sequência , Sintenia/genética , Transcrição Genética , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética
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