RESUMO
INTRODUCTION: Hydatidiform mole is one of the gestational trophoblastic disease and comprises complete (CM) and partial moles (PM), which carries a risk of developing persistence disease, invasive mole or choriocarcinoma. MicroRNAs (miRNAs) have been discovered in various tissues, including neoplastic tissues. Its role in the pathogenesis of molar pregnancy or as biomarkers are still largely uncertain. The aim of this study is to identify the differentially expressed miRNAs in CM and PM. MATERIALS AND METHODS: Using next-generation sequencing, the miRNAs profiles of CM (n=3) and PM (n=3) moles, including placenta of non-molar abortus (n=3) as control were determined. The differentially expressed miRNAs between each group were analysed. Subsequently, bioinformatics analysis using miRDB and Targetscan was utilised to predict target genes. RESULTS: We found 10 differentially expressed miRNAs in CMs and PMs, compared to NMAs, namely miR- 518a-5p, miR-423-3p, miR-503-5p, miR-302a-3p, and miR-1323. The other 5 miRNAs were novel, not listed in the known database. The 3 differentially expressed miRNAs in CMs were predicted to commonly target ZTBT46 and FAM73B mRNAs. DISCUSSION: miR-518 was consistently observed to be downregulated in CM versus PM, and CM versus NMA. Further bioinformatic analysis to provide insight into the possible role of these miRNAs in the pathogenesis of HMs, progression of disease and as potential diagnostic biomarkers as well as therapeutic targets for HMs is needed.
Assuntos
Coriocarcinoma , Mola Hidatiforme , MicroRNAs , Toupeiras , Gravidez , Feminino , Humanos , Animais , Toupeiras/genética , Mola Hidatiforme/genética , MicroRNAs/genética , Biomarcadores , Perfilação da Expressão GênicaRESUMO
Golden moles (Chrysochloridae) and marsupial moles (Notoryctidae) are textbook examples of convergent evolution. Both taxa are highly adapted to subterranean lifestyles and have powerful limbs for digging through the soil/sand, ears that are adapted for low-frequency hearing, vestigial eyes that are covered by skin and fur, and the absence of optic nerve connections between the eyes and the brain. The eyes of marsupial moles also lack a lens as well as retinal rods and cones. Two hypotheses have been proposed to account for the greater degeneracy of the eyes of marsupial moles than golden moles. First, marsupial moles may have had more time to adapt to their underground habitat than other moles. Second, the eyes of marsupial moles may have been rapidly and recently vestigialized to (1) reduce the injurious effects of sand getting into the eyes and (2) accommodate the enlargement of lacrimal glands that keep the nasal cavity moist and prevent the entry of sand into the nasal passages during burrowing. Here, we employ molecular evolutionary methods on DNA sequences for 38 eye genes, most of which are eye-specific, to investigate the timing of relaxed selection (=neutral evolution) for different groups of eye-specific genes that serve as proxies for distinct functional components of the eye (rod phototransduction, cone phototransduction, lens/cornea). Our taxon sampling included 12 afrothere species, of which two are golden moles (Amblysomus hottentotus, Chrysochloris asiatica), and 28 marsupial species including two individuals of the southern marsupial mole (Notoryctes typhlops). Most of the sequences were mined from databases, but we also provide new genome data for A. hottentotus and one of the two N. typhlops individuals. Even though the eyes of golden moles are less degenerate than the eyes of marsupial moles, there are more inactivating mutations (e.g., frameshift indels, premature stop codons) in their cone phototransduction and lens/cornea genes than in orthologous genes of the marsupial mole. We estimate that cone phototransduction recovery genes were inactivated first in each group, followed by lens/cornea genes and then cone phototransduction activation genes. All three groups of genes were inactivated earlier in golden moles than in marsupial moles. For the latter, we estimate that lens/cornea genes were inactivated ~17.8 million years ago (MYA) when stem notoryctids were burrowing in the soft soils of Australian rainforests. Selection on phototransduction activation genes was relaxed much later (5.38 MYA), during the early stages of Australia's aridification that produced coastal sand plains and eventually sand dunes. Unlike cone phototransduction activation genes, rod phototransduction activation genes are intact in both golden moles and one of the two individuals of N. typhlops. A second marsupial mole individual has just a single inactivating mutation in one of the rod phototransduction activation genes (PDE6B). One explanation for this result is that some rod phototransduction activation genes are pleiotropic and are expressed in extraocular tissues, possibly in conjunction with sperm thermotaxis.
Assuntos
Marsupiais , Toupeiras , Animais , Masculino , Afrotheria , Austrália , Marsupiais/genética , Toupeiras/genética , Filogenia , Areia , SêmenRESUMO
Changes in gene expression represent an important source of phenotypic innovation. Yet how such changes emerge and impact the evolution of traits remains elusive. Here, we explore the molecular mechanisms associated with the development of masculinizing ovotestes in female moles. By performing integrative analyses of epigenetic and transcriptional data in mole and mouse, we identified the co-option of SALL1 expression in mole ovotestes formation. Chromosome conformation capture analyses highlight a striking conservation of the 3D organization at the SALL1 locus, but an evolutionary divergence of enhancer activity. Interspecies reporter assays support the capability of mole-specific enhancers to activate transcription in urogenital tissues. Through overexpression experiments in transgenic mice, we further demonstrate the capability of SALL1 to induce kidney-related gene programs, which are a signature of mole ovotestes. Our results highlight the co-option of gene expression, through changes in enhancer activity, as a plausible mechanism for the evolution of traits.
Assuntos
Rim , Toupeiras , Animais , Feminino , Camundongos , Rim/metabolismo , Camundongos Transgênicos , Toupeiras/genéticaRESUMO
In recent years, the number of mole species with species status confirmed by genetic methods has been continuously increasing. Unfortunately, cytogenetic data are not yet available for all species. Here, for the first time, a GTG-banded karyotype of the small-toothed mole from Vietnam, Euroscaptor parvidens, a representative of the Eastern clade of the genus Euroscaptor, has been described. Through comparative analysis of available Euroscaptor (Euroscaptor parvidens, Euroscaptor klossi, and Euroscaptor malayana) and Oreoscaptor (Oreoscaptor mizura) karyotypes, we found cytogenetic signatures for each of the studied species. Zoo-FISH with sorted chromosomes of the Siberian mole (Talpa altaica) on chromosome sets of the small-toothed mole (E. parvidens), the small Japanese mole (Mogera imaizumii) from the closely related genus, and the Japanese shrew mole (Urotrichus talpoides) from the tribe Urotrichini made it possible to identify syntenic regions between these species. We propose a possible ancestral karyotype of the tribe and, based on it, traced the features of chromosomal rearrangements accompanying the divergence of moles. The low rates of chromosomal evolution within the species of the genus Talpa-T. altaica and T. europaea-and the high rates of karyotypic reshuffling within the Asian genera of the tribe were confirmed. The karyotype of the Japanese mountain mole O. mizura seems to be the most conserved among the Asian moles. The most frequently occurring types of chromosomal rearrangements in moles are the pericentric inversions and amplification of heterochromatin. The pericentric inversions on four pairs of autosomes are shared between the closely related genera Euroscaptor, Oreoscaptor, and Mogera, while many more apomorphic rearrangements have occurred in each lineage additionally. The highest rate of chromosomal changes, with five rearrangements occurring over approximately 7 million years, was recorded in the lineage of the small-toothed mole.
Assuntos
Toupeiras , Animais , Toupeiras/genética , Cariotipagem , Citogenética , Cariótipo , Musaranhos/genéticaRESUMO
A new medium-sized shrew mole species of the genus Uropsilus from Mount Fansipan, Hoang Lien National Park, Lao Cai Province, northwestern Vietnam is described based on morphological and molecular differences. Uropsilus fansipanensis sp. nov. is distinguished from the other Uropsilus species by the combination of the following features: the dorsum is lightly reddish-brown and venter is dark gray; the dark gray tail is long and slender, with a scattered white base and short bristle hairs; orbital process is oriented upwards posteriorly; lacrimal foramen is well developed and much larger than infraorbital foramen; the lower first premolar is approximately the same size as the lower third premolar. Genetic distances in terms of mitochondrial cytochrome b from other Uropsilus species presented pairwise divergences from 8.63 to 20.70%. To date, the new species is known to exist only in the type locality of Mt. Fansipan, a wet and cold temperate climate area with an upper montane forest at an elevation of approximately 2900 m, forming the southernmost distribution of the genus Uropsilus.
Assuntos
Eulipotyphla , Toupeiras , Animais , Filogenia , Musaranhos , Vietnã , Toupeiras/genéticaRESUMO
The complete mitogenome sequence of Talpa martinorum, a recently described Balkan endemic mole, was assembled from next generation sequence data. The mitogenome is similar to that of the three other Talpa species sequenced to date, being 16,835 bp in length, and containing 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, an origin of L-strand replication, and a control region or D-loop. Compared to other Talpa mitogenomes sequenced to date, that of T. martinorum differs in the length of D-loop and stop codon usage. TAG and T-- are the stop codons for the ND1 and ATP8 genes, respectively, in T. martinorum, whilst TAA acts as a stop codon for both ND1 and ATP8 in the other three Talpa species sequenced. Phylogeny reconstructions based on Maximum Likelihood and Bayesian inference analyses yielded phylogenies with similar topologies, demonstrating that T. martinorum nests within the western lineage of the genus, being closely related to T. aquitania and T. occidentalis.
Assuntos
Genoma Mitocondrial , Toupeiras , Animais , Teorema de Bayes , Códon de Terminação , Toupeiras/genética , Filogenia , RNA de Transferência/genéticaRESUMO
We have previously estimated the evolutionary rate (number of substitutions/site/million years) of mitochondrial cytochrome b gene (Cytb) sequences in rodents and moles to be about 0.11 at more recent divergence times of tens of thousands of years, and to decrease rapidly to about 0.03 at more distant divergence times. Because this time dependency is thought to be caused by the removal of mildly deleterious substitutions in later generations, we focused in this study on the abundance of nonsynonymous substitutions. We collected 23 haplogroups of Cytb with signals of late Quaternary population expansion events from rodents and moles and categorized them into three groups for comparison based on predicted expansion start time: 5,000-15,000 years ago (Group I), ca. 53,000 years ago (Group II) and 130,000-230,000 years ago (Group III). We counted the numbers of nonsynonymous and synonymous substitutions in all haplogroups. The rates of nonsynonymous substitutions were lowest in Groups II and III (0.08-0.22), whereas those in Group I varied markedly. We further classified Group I into two subgroups based on high (0.29-0.43) and low (0.09-0.20) nonsynonymous substitution rates, which were likely to be associated with the start of the expansion within 10,000 years and at around 15,000 years ago, respectively. The Group II and III networks had two- or three-step star-shaped structures and tended to exhibit frequent and less frequent nonsynonymous substitutions on exterior and interior branches, respectively. Based on temporal dynamics, nonsynonymous mitochondrial DNA (mtDNA) substitutions in small mammals accounted for at most 40% of all substitutions during the early evolutionary stage and then rapidly declined, dropping to approximately 15%. The results of this study provide a good explanation of the time-dependent trend in the mtDNA evolution rate predicted in previous work.
Assuntos
Genes Mitocondriais , Toupeiras , Animais , Roedores/genética , Toupeiras/genética , Citocromos b/genética , DNA Mitocondrial/genética , Mamíferos/genética , Filogenia , Evolução MolecularRESUMO
Pregnancies, including ones that follow sexual assaults, occasionally produce hydatidiform moles. The alleged fathers (AFs) of moles have been tested for paternity by identifying the mole's locus phenotype-the one or two visible paternal obligate alleles (POAs) per locus. The probability that the mole inherited the POAs from the AF was divided by the probability that the mole inherited the POAs from a random man. This likelihood ratio (LR) would increase if the mole's specific genotype was known. Moles are generated in five different ways that produce five distinct genotypes. Examining a mole's multilocus STR profile reveals a mole's pathogenesis, determines locus genotypes, and increases paternity LRs.
Assuntos
Mola Hidatiforme , Toupeiras , Neoplasias Uterinas , Alelos , Animais , Feminino , Genótipo , Humanos , Mola Hidatiforme/genética , Masculino , Toupeiras/genética , Paternidade , Gravidez , Neoplasias Uterinas/genéticaRESUMO
During a terrestrial vertebrate survey of the Dabie Mountains in Anhui Province, eastern China, we collected four Asian shrew mole specimens (hereafter, shrew moles). Based on published literature and comparison with previously collected materials, the four specimens were similar to shrew moles from the mountains of Southwest China; however, no species in this group has been previously recorded from the Dabie Mountains. The genetic and morphological characteristics of the specimens were analyzed, based upon which a new species of shrew mole is described, named Uropsilus dabieshanensis sp. nov.
Assuntos
Toupeiras/classificação , Animais , China , Toupeiras/genética , Especificidade da EspécieRESUMO
Afrotheria is a clade of African-origin species with striking dissimilarities in appearance and habitat. In this study, we compared whole proteome sequences of six Afrotherian species to obtain a broad viewpoint of their underlying molecular make-up, to recognize potentially unique proteomic signatures. We find that 62% of the proteomes studied here, predominantly involved in metabolism, are orthologous, while the number of homologous proteins between individual species is as high as 99.5%. Further, we find that among Afrotheria, L. africana has several orphan proteins with 112 proteins showing < 30% sequence identity with their homologues. Rigorous sequence searches and complementary approaches were employed to annotate 156 uncharacterized protein sequences and 28 species-specific proteins. For 122 proteins we predicted potential functional roles, 43 of which we associated with protein- and nucleic-acid binding roles. Further, we analysed domain content and variations in their combinations within Afrotheria and identified 141 unique functional domain architectures, highlighting proteins with potential for specialized functions. Finally, we discuss the potential relevance of highly represented protein families such as MAGE-B2, olfactory receptor and ribosomal proteins in L. africana and E. edwardii, respectively. Taken together, our study reports the first comparative study of the Afrotherian proteomes and highlights salient molecular features.
Assuntos
Eutérios/classificação , Eutérios/genética , Animais , Sequência Conservada , Bases de Dados de Proteínas , Elefantes/classificação , Elefantes/genética , Elefantes/metabolismo , Eutérios/metabolismo , Evolução Molecular , Ouriços/classificação , Ouriços/genética , Ouriços/metabolismo , Anotação de Sequência Molecular , Toupeiras/classificação , Toupeiras/genética , Toupeiras/metabolismo , Filogenia , Domínios Proteicos , Proteínas/química , Proteínas/genética , Proteínas/metabolismo , Proteoma/genética , Proteômica , Musaranhos/classificação , Musaranhos/genética , Musaranhos/metabolismo , Especificidade da Espécie , Trichechus manatus/classificação , Trichechus manatus/genética , Trichechus manatus/metabolismoRESUMO
Evolution sometimes proceeds by loss, especially when structures and genes become dispensable after an environmental shift relaxes functional constraints. Subterranean vertebrates are outstanding models to analyze this process, and gene decay can serve as a readout. We sought to understand some general principles on the extent and tempo of the decay of genes involved in vision, circadian clock, and pigmentation in cavefishes. The analysis of the genomes of two Cuban species belonging to the genus Lucifuga provided evidence for the largest loss of eye-specific genes and nonvisual opsin genes reported so far in cavefishes. Comparisons with a recently evolved cave population of Astyanax mexicanus and three species belonging to the Chinese tetraploid genus Sinocyclocheilus revealed the combined effects of the level of eye regression, time, and genome ploidy on eye-specific gene pseudogenization. The limited extent of gene decay in all these cavefishes and the very small number of loss-of-function mutations per pseudogene suggest that their eye degeneration may not be very ancient, ranging from early to late Pleistocene. This is in sharp contrast with the identification of several vision genes carrying many loss-of-function mutations in ancient fossorial mammals, further suggesting that blind fishes cannot thrive more than a few million years in cave ecosystems.
Assuntos
Relógios Circadianos/genética , Peixes/genética , Mutação com Perda de Função , Toupeiras/genética , Pigmentação/genética , Visão Ocular/genética , Animais , Cavernas , Pseudogenes , Seleção Genética , Peixe-ZebraRESUMO
Linking genomic variation to phenotypical traits remains a major challenge in evolutionary genetics. In this study, we use phylogenomic strategies to investigate a distinctive trait among mammals: the development of masculinizing ovotestes in female moles. By combining a chromosome-scale genome assembly of the Iberian mole, Talpa occidentalis, with transcriptomic, epigenetic, and chromatin interaction datasets, we identify rearrangements altering the regulatory landscape of genes with distinct gonadal expression patterns. These include a tandem triplication involving CYP17A1, a gene controlling androgen synthesis, and an intrachromosomal inversion involving the pro-testicular growth factor gene FGF9, which is heterochronically expressed in mole ovotestes. Transgenic mice with a knock-in mole CYP17A1 enhancer or overexpressing FGF9 showed phenotypes recapitulating mole sexual features. Our results highlight how integrative genomic approaches can reveal the phenotypic impact of noncoding sequence changes.
Assuntos
Adaptação Fisiológica/genética , Fator 9 de Crescimento de Fibroblastos/genética , Toupeiras/genética , Elementos Reguladores de Transcrição , Diferenciação Sexual/genética , Esteroide 17-alfa-Hidroxilase/genética , Animais , Inversão Cromossômica , Conjuntos de Dados como Assunto , Feminino , Regulação da Expressão Gênica , Genoma , Camundongos , Camundongos Transgênicos , Sequências de Repetição em Tandem , Testosterona/sangue , Testosterona/genéticaRESUMO
Golden moles (Family Chrysochloridae) are small subterranean mammals, endemic to sub-Saharan Africa, and many of the 21 species are listed as threatened on the IUCN Red List. Most species have highly restricted ranges; however two species, the Hottentot golden mole (Amblysomus hottentotus) and the Cape golden mole (Chrysochloris asiatica) have relatively wide ranges. We recently uncovered cryptic diversity within A. hottentotus, through a phylogeographic analysis of this taxon using two mitochondrial gene regions and a nuclear intron. To further investigate this cryptic diversity, we generated nuclear SNP data from across the genome of A. hottentotus, by means of double-digest restriction-site associated DNA sequencing (ddRADSeq), and mapped reads to the Cape golden mole genome. We conducted a phylogenetic analysis and investigated population differentiation. Our results support the distinctiveness of A. h. meesteri. Furthermore, we provide evidence from nuclear SNPs in support of our previous finding that Central coastal samples represent a unique cryptic lineage that is highly divergent from A. h. pondoliae farther south. Although mtDNA suggests that Umtata may represent a unique lineage sister to A. h. longiceps, mito-nuclear discordance from our RADseq data indicate that these samples may instead be closer to A. h. pondoliae, and therefore may not represent a distinct lineage. We stress the importance of recognizing that understudied populations, such as that of Umtata, may represent populations or ESUs under threat and in need of conservation attention. We present a high-quality filtered SNP dataset, comprising thousands of SNPs, which may serve as a useful resource for future golden mole studies. We have thus added to the growing body of research demonstrating the power and utility of RADseq to investigate population differentiation.
Assuntos
Eutérios/classificação , Toupeiras/classificação , Animais , DNA Mitocondrial , Eutérios/genética , Toupeiras/genética , Filogenia , Filogeografia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , África do SulRESUMO
Analysing the impact of anthropogenic and natural river barriers on the dispersal of aquatic and semi-aquatic species may be critical for their conservation. Knowledge of kinship relationships between individuals and reconstructions of pedigrees obtained using genomic data can be extremely useful, not only for studying the social organization of animals, but also inferring contemporary dispersal and quantifying the effect of specific barriers on current connectivity. In this study, we used kinship data to analyse connectivity patterns in a small semi-aquatic mammal, the Pyrenean desman (Galemys pyrenaicus), in an area comprising two river systems with close headwaters and dams of various heights and types. Using a large SNP dataset from 70 specimens, we obtained kinship categories and reconstructed pedigrees. To quantify the barrier effect of specific obstacles, we built kinship networks and devised a method based on the assortativity coefficient, which measures the proportion between observed and expected kinship relationships across a barrier. The estimation of this parameter enabled us to infer that the most important barrier in the area was the watershed divide between the rivers, followed by a dam on one of the rivers. Other barriers did not significantly reduce the expected number of kinship relationships across them. This strategy and the information obtained with it may be crucial in determining the most important connectivity problems in an area and help develop conservation plans aimed at improving genetic exchange between populations of threatened species.
Assuntos
Distribuição Animal , Genética Populacional , Toupeiras/classificação , Toupeiras/genética , Animais , Genótipo , Filogenia , Polimorfismo de Nucleotídeo Único , RiosRESUMO
The complete mitogenome of Talpa occidentalis, the Iberian mole, was sequenced using a combination of the Illumina and Sanger methods. The 16,962 bp genome obtained contains 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs, and a control region. Thirty-seven identical repetitions of a 10-nucleotide (CACACGTACG) repeat element were identified in the non-coding control region (D-loop). The number, order, and orientation of the mitochondrial genes are the same as in T. europaea, the only mitogenome published so far for this genus. These two mitogenomes differ only at the repeat element included in the control region. The phylogeny obtained for the Talpidae species using the protein-coding genes of these mitogenomes agrees with the current classification of this family.
Assuntos
Toupeiras/genética , Animais , Composição de Bases/genética , Sequência de Bases , Espécies em Perigo de Extinção , Genes Mitocondriais , Genoma Mitocondrial/genética , Filogenia , Portugal , RNA Ribossômico/genética , RNA de Transferência/genética , Análise de Sequência de DNA/métodos , EspanhaRESUMO
Regressive evolution involves the degradation of formerly useful traits as organisms invade novel ecological niches. In animals, committing to a strict subterranean habit can lead to regression of the eyes, likely due to a limited exposure to light. Several lineages of subterranean mammals show evidence of such degeneration, which can include decreased organization of the retina, malformation of the lens, and subcutaneous positioning of the eye. Advances in DNA sequencing have revealed that this regression co-occurs with a degradation of genomic loci encoding visual functions, including protein-coding genes. Other dim light-adapted vertebrates with normal ocular anatomy, such as nocturnal and aquatic species, also demonstrate evidence of visual gene loss, but the absence of comparative studies has led to the untested assumption that subterranean mammals are special in the degree of this genomic regression. Additionally, previous studies have shown that not all vision genes have been lost in subterranean mammals, but it is unclear whether they are under relaxed selection and will ultimately be lost, are maintained due to pleiotropy or if natural selection is favoring the retention of the eye and certain critical underlying loci. Here I report that vision gene loss in subterranean mammals tends to be more extensive in quantity and differs in distribution from other dim light-adapted mammals, although some committed subterranean mammals demonstrate significant overlap with nocturnal microphthalmic species. In addition, blind subterranean mammals retain functional orthologs of non-pleiotropic visual genes that are evolving at rates consistent with purifying selection. Together, these results suggest that although living underground tends to lead to major losses of visual functions, natural selection is maintaining genes that support the eye, perhaps as an organ for circadian and/or circannual entrainment.
Assuntos
Evolução Molecular , Mamíferos/fisiologia , Visão Ocular/genética , Animais , Ecossistema , Olho/anatomia & histologia , Mamíferos/genética , Ratos-Toupeira/genética , Ratos-Toupeira/fisiologia , Toupeiras/genética , Toupeiras/fisiologiaRESUMO
Fossorial talpid moles use their limbs predominantly for digging, which explains their highly specialized anatomy. The humerus is particularly short and dorsoventrally rotated, with broadened distal and proximal parts where muscles attach and which facilitate powerful abductive movements. The radius and ulna are exceptionally robust and short. The ulna has an expanded olecranon process. The femur is generalized, but the fused tibia-fibula complex is short and robust. To understand the developmental bases of these specializations, we studied expression patterns of four 5' Hox genes in the fossorial Iberian mole (Talpa occidentalis). These genes are known to play major roles in patterning the developing limb skeleton in the mouse, with which comparisons were made (Mus musculus, C57BL/6Jico strain). We find that HoxA9 expression is spatially expanded in the developing stylopodial area in the mole forelimb, compared to the less specialized mouse forelimb and mole hind limb. HoxD9 expression does not extend into the thoracic body wall in the mole forelimb in contrast to the mouse, and is also reduced in the presumptive zeugopodium in mole forelimb, compared to mouse. Expression of HoxD11 is upregulated in the mole in the postaxial area of the hind limb zeugopod, compared to the mouse. On the other hand, HoxD13 is downregulated in the postaxial zeugopodial area in the forelimb of the mole, compared to the mouse. The differences in the expression patterns of these 5' Hox genes between Talpa and Mus are an indication of the developmental changes going hand in hand with anatomical digging adaptations in the mole adult.
Assuntos
Membro Anterior/embriologia , Genes Homeobox , Proteínas de Homeodomínio/genética , Toupeiras/anatomia & histologia , Toupeiras/genética , Animais , Embrião de Mamíferos/metabolismo , Feminino , Membro Anterior/metabolismo , Camundongos , Camundongos Endogâmicos C57BLRESUMO
The mammalian family Talpidae (moles, shrew moles, desmans) is characterized by diverse ecomorphologies associated with terrestrial, semi-aquatic, semi-fossorial, fossorial, and aquatic-fossorial lifestyles. Prominent specializations involved with these different lifestyles, and the transitions between them, pose outstanding questions regarding the evolutionary history within the family, not only for living but also for fossil taxa. Here, we investigate the phylogenetic relationships, divergence times, and biogeographic history of the family using 19 nuclear and 2 mitochondrial genes (â¼16 kb) from â¼60% of described species representing all 17 genera. Our phylogenetic analyses help settle classical questions in the evolution of moles, identify an ancient (mid-Miocene) split within the monotypic genus Scaptonyx, and indicate that talpid species richness may be nearly 30% higher than previously recognized. Our results also uniformly support the monophyly of long-tailed moles with the two shrew mole tribes and confirm that the Gansu mole is the sole living Asian member of an otherwise North American radiation. Finally, we provide evidence that aquatic specializations within the tribes Condylurini and Desmanini evolved along different morphological trajectories, though we were unable to statistically reject monophyly of the strictly fossorial tribes Talpini and Scalopini.
Assuntos
Toupeiras/genética , Musaranhos/genética , Animais , Evolução Biológica , Classificação/métodos , Bases de Dados de Ácidos Nucleicos , Variação Genética , Filogenia , Análise de Sequência de DNA/métodos , Especificidade da EspécieRESUMO
Here, we describe cDNA cloning and purification of the ghrelin gene sequences and ghrelin peptides from the Japanese true mole, Mogera imaizumii. The gene spans >2.9kbp, has four exons and three introns, and shares structural similarity with those of terrestrial animals. Mature mole ghrelin peptide was predicted to be 28 amino acids long (GSSFLSPEHQKVQQRKESKKPPSKPQPR) and processed from a prepropeptide of 116 amino acids. To further elucidate molecular characteristics, we purified ghrelin peptides from mole stomach. By mass spectrometry, we found that the mole ghrelin peptides had higher ratios of the odd-number fatty acids (C9 and C11 as much as C8) attached to the third serine residue than other vertebrate ghrelin. Truncated forms of ghrelins such as [1-27], [1-19], [1-16] and [1-15], and that lacked the 14th glutamine residue (des-Gln14 ghrelin) were produced in the stomach. Marked expression of ghrelin mRNA in lung was observed as in stomach and brain. Phylogenetic analysis indicated that the branch of M. imaizumii has slightly higher dN/dS ratios (the nucleotide substitution rates at non-synonymous and synonymous sites) than did other eulipotyphlans. Peptide length was positively correlated with human ghrelin receptor activation, whereas the length of fatty-acyl chains showed no obvious functional correlation. The basal higher luciferase activities of the 5'-proximal promoter region of mole ghrelin were detected in ghrelin-negative C2C12 cells and hypoxic culture conditions impaired transcriptional activity. These results indicated that moles have acquired diverse species of ghrelin probably through distinctive fatty acid metabolism because of their food preferences. The results provide a gateway to understanding ghrelin metabolism in fossorial animals.
Assuntos
DNA Complementar/genética , Grelina/genética , Toupeiras/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Expressão GênicaRESUMO
The Greater Maputaland-Pondoland-Albany (GMPA) region of southern Africa was recently designated as a centre of vertebrate endemism. The phylogeography of the vertebrate taxa occupying this region may provide insights into the evolution of faunal endemism in south-eastern Africa. Here we investigate the phylogeographic patterns of an understudied small mammal species assemblage (Amblysomus) endemic to the GMPA, to test for cryptic diversity within the genus, and to better understand diversification across the region. We sampled specimens from 50 sites across the distributional range of Amblysomus, with emphasis on the widespread A. hottentotus, to analyse geographic patterns of genetic diversity using mitochondrial DNA (mtDNA) and nuclear intron data. Molecular dating was used to elucidate the evolutionary and phylogeographic history of Amblysomus. Our phylogenetic reconstructions show that A. hottentotus comprises several distinct lineages, or evolutionarily significant units (ESUs), some with restricted geographic ranges and thus worthy of conservation attention. Divergence of the major lineages dated to the early Pliocene, with later radiations in the GMPA during the late-Pliocene to early-Pleistocene. Evolutionary diversification within Amblysomus may have been driven by uplift of the Great Escarpment c. 5-3 million years ago (Ma), habitat changes associated with intensification of the east-west rainfall gradient across South Africa and the influence of subsequent global climatic cycles. These drivers possibly facilitated geographic spread of ancestral lineages, local adaptation and vicariant isolation. Our study adds to growing empirical evidence identifying East and southern Africa as cradles of vertebrate diversity.