Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.428
Filtrar
1.
BMC Evol Biol ; 20(1): 113, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32883209

RESUMO

BACKGROUND: The study of speciation has expanded with the increasing availability and affordability of high-resolution genomic data. How the genome evolves throughout the process of divergence and which regions of the genome are responsible for causing and maintaining that divergence have been central questions in recent work. Here, we use three pairs of species from the recently diverged bee hummingbird clade to investigate differences in the genome at different stages of speciation, using divergence times as a proxy for the speciation continuum. RESULTS: Population measures of relative differentiation between hybridizing species reveal that different chromosome types diverge at different stages of speciation. Using FST as our relative measure of differentiation we found that the sex chromosome shows signs of divergence early in speciation. Next, small autosomes (microchromosomes) accumulate highly diverged genomic regions, while the large autosomes (macrochromosomes) accumulate genomic regions of divergence at a later stage of speciation. CONCLUSIONS: Our finding that genomic windows of elevated FST accumulate on small autosomes earlier in speciation than on larger autosomes is counter to the prediction that FST increases with size of chromosome (i.e. with decreased recombination rate), and is not represented when weighted average FST per chromosome is compared with chromosome size. The results of this study suggest that multiple chromosome characteristics such as recombination rate and gene density combine to influence the genomic locations of signatures of divergence.


Assuntos
Evolução Biológica , Aves/classificação , Especiação Genética , Animais , Cromossomos/genética , Genoma , Genômica , Hibridização Genética , Cromossomos Sexuais/genética
2.
Crit Care ; 24(1): 405, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32646459

RESUMO

More men than women have died from COVID-19. Genes encoded on X chromosomes, and sex hormones may explain the decreased fatality of COVID-19 in women. The angiotensin-converting enzyme 2 gene is located on X chromosomes. Men, with a single X chromosome, may lack the alternative mechanism for cellular protection after exposure to SARS-CoV-2. Some Toll-like receptors encoded on the X chromosomes can sense SARS-CoV-2 nucleic acids, leading to a stronger innate immunity response in women. Both estrogen and estrogen receptor-α contribute to T cell activation. Interventional approaches including estrogen-related compounds and androgen receptor antagonists may be considered in patients with COVID-19.


Assuntos
Infecções por Coronavirus/mortalidade , Disparidades nos Níveis de Saúde , Pneumonia Viral/mortalidade , Caracteres Sexuais , Feminino , Hormônios Esteroides Gonadais , Humanos , Imunidade Inata , Masculino , Pandemias , Cromossomos Sexuais/genética
3.
Proc Natl Acad Sci U S A ; 117(24): 13626-13636, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32487729

RESUMO

Humans homozygous or hemizygous for variants predicted to cause a loss of function (LoF) of the corresponding protein do not necessarily present with overt clinical phenotypes. We report here 190 autosomal genes with 207 predicted LoF variants, for which the frequency of homozygous individuals exceeds 1% in at least one human population from five major ancestry groups. No such genes were identified on the X and Y chromosomes. Manual curation revealed that 28 variants (15%) had been misannotated as LoF. Of the 179 remaining variants in 166 genes, only 11 alleles in 11 genes had previously been confirmed experimentally to be LoF. The set of 166 dispensable genes was enriched in olfactory receptor genes (41 genes). The 41 dispensable olfactory receptor genes displayed a relaxation of selective constraints similar to that observed for other olfactory receptor genes. The 125 dispensable nonolfactory receptor genes also displayed a relaxation of selective constraints consistent with greater redundancy. Sixty-two of these 125 genes were found to be dispensable in at least three human populations, suggesting possible evolution toward pseudogenes. Of the 179 LoF variants, 68 could be tested for two neutrality statistics, and 8 displayed robust signals of positive selection. These latter variants included a known FUT2 variant that confers resistance to intestinal viruses, and an APOL3 variant involved in resistance to parasitic infections. Overall, the identification of 166 genes for which a sizeable proportion of humans are homozygous for predicted LoF alleles reveals both redundancies and advantages of such deficiencies for human survival.


Assuntos
Genética Humana , Mutação com Perda de Função , Alelos , Apolipoproteínas L/genética , Fucosiltransferases/genética , Variação Genética , Homozigoto , Humanos , Proteínas/genética , Cromossomos Sexuais/genética
4.
Nat Commun ; 11(1): 2179, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358487

RESUMO

Genomic outcomes of hybridization depend on selection and recombination in hybrids. Whether these processes have similar effects on hybrid genome composition in contemporary hybrid zones versus ancient hybrid lineages is unknown. Here we show that patterns of introgression in a contemporary hybrid zone in Lycaeides butterflies predict patterns of ancestry in geographically adjacent, older hybrid populations. We find a particularly striking lack of ancestry from one of the hybridizing taxa, Lycaeides melissa, on the Z chromosome in both the old and contemporary hybrids. The same pattern of reduced L. melissa ancestry on the Z chromosome is seen in two other ancient hybrid lineages. More generally, we find that patterns of ancestry in old or ancient hybrids are remarkably predictable from contemporary hybrids, which suggests selection and recombination affect hybrid genomes in a similar way across disparate time scales and during distinct stages of speciation and species breakdown.


Assuntos
Borboletas/genética , Hibridização Genética/genética , Cromossomos Sexuais/genética , Animais , Fluxo Gênico , Loci Gênicos , Especiação Genética , Genética Populacional , Genoma de Inseto , Genômica , Filogenia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA
5.
Sci Rep ; 10(1): 8576, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444700

RESUMO

The Japanese murrelet (Synthliboramphus wumizusume) is an endangered small seabird species in Japan. Molecular sexing using PCR targeting of the gene encoding chromodomain helicase DNA-binding protein 1(CHD1) has been used for sex identification. Specifically, PCR using any of three commonly used primer sets (CHD1F/1R, 2550F/2718R and P2/P8) has permitted sexing in many bird species. CHD1F/1R and 2550F/2718R permitted molecular sexing in Japanese murrelet; however, P2/P8 did not permit. To generate a primer pair that permits efficient molecular sexing in this species, a new primer set, CHD1F1/1R1, was prepared to permit amplification of smaller products from degraded DNA samples. The electrophoretic patterns of PCR products amplified with the new primer set were easily classified as female or male. Additionally, the PCR product indicated the presence of a polymorphism in the fragment from chromosome W. The PCR fragments of long-type (WL) and short-type (WS) polymorphisms were observed only in females. When the distribution of the CHD1 gene on chromosome W of 61 female Japanese murrelet on Biroujima Island in Miyazaki Prefecture, WL and WS were observed in 90.2% and 9.8%. The DNA polymorphism is derived from the number of copies of a 32-bp-repeat unit, with WL and WS corresponding to two and one 32-bp-repeats, respectively.


Assuntos
Charadriiformes/genética , Polimorfismo Genético , Cromossomos Sexuais/genética , Sequências de Repetição em Tandem/genética , Animais , Espécies em Perigo de Extinção , Feminino , Masculino , Análise para Determinação do Sexo
6.
Nat Commun ; 11(1): 1964, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327641

RESUMO

Sex determination mechanisms often differ even between related species yet the evolution of sex chromosomes remains poorly understood in all but a few model organisms. Some nematodes such as Caenorhabditis elegans have an XO sex determination system while others, such as the filarial parasite Brugia malayi, have an XY mechanism. We present a complete B. malayi genome assembly and define Nigon elements shared with C. elegans, which we then map to the genomes of other filarial species and more distantly related nematodes. We find a remarkable plasticity in sex chromosome evolution with several distinct cases of neo-X and neo-Y formation, X-added regions, and conversion of autosomes to sex chromosomes from which we propose a model of chromosome evolution across different nematode clades. The phylum Nematoda offers a new and innovative system for gaining a deeper understanding of sex chromosome evolution.


Assuntos
Evolução Molecular , Nematoides/genética , Infecções por Nematoides/parasitologia , Cromossomos Sexuais/genética , Animais , Brugia Malayi/genética , Caenorhabditis elegans/genética , Mapeamento Cromossômico , Feminino , Regulação da Expressão Gênica , Genoma Helmíntico/genética , Humanos , Masculino , Nematoides/classificação , Sequências Repetitivas de Ácido Nucleico/genética , Processos de Determinação Sexual/genética
7.
Cytogenet Genome Res ; 160(3): 118-123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32248198

RESUMO

We present 2 cases of double mosaic aneuploidy harboring 2 or more different aneuploid cell lines, but no line with a normal chromosome constitution. One of these cases presented mosaicism of sex chromosome aneuploid cell lines (47,XXX/45,X) along with another line containing an autosomal trisomy (47,XX,+8), while the other case showed mosaicism of 2 different autosomal trisomy cell lines (47,XY,+5 and 47,XY,+8). To elucidate the mechanisms underlying these mosaicisms, we conducted molecular cytogenetic analyses. Genotyping data from the SNP microarray indicated that 2 sequential meiotic or early postzygotic segregation errors likely had occurred followed by natural selection. These cases suggest that frequent segregation errors and selection events in the meiotic and early postzygotic stages lead to this condition.


Assuntos
Linhagem da Célula/genética , Mosaicismo , Cromossomos Sexuais/genética , Trissomia/genética , Aneuploidia , Análise Citogenética , Feminino , Humanos , Lactente , Pessoa de Meia-Idade , Trissomia/patologia
8.
Biol Lett ; 16(4): 20200082, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32315592

RESUMO

Sex chromosomes in birds have long been considered to be extremely stable. However, this notion has lately been challenged by findings of independent autosome-sex chromosome fusions within songbirds, several of which occur within a single clade, the superfamily Sylvioidea. To understand what ecological and evolutionary processes drive changes in sex chromosome systems, we need complete descriptions of sex chromosome diversity across taxonomic groups. Here, we characterize the sex chromosome systems across Sylvioidea using whole-genome data of species representatives of 10 different families, including two published and eight new genomes. We describe a novel fusion in the family Cisticolidae (represented by Cisticola juncidis) involving a part of chromosome 4. We also confirm the previously identified fusion between chromosome Z and a part of chromosome 4A in all 10 families and show that fusions involving parts of chromosomes 3 and 5 are not found outside the families where they were first discovered (Alaudidae and Panuridae). These findings add to the complexity of the sex chromosome system in Sylvioidea, where four independent autosome-sex chromosome fusions have now been identified.


Assuntos
Passeriformes , Aves Canoras , Animais , Evolução Biológica , Genoma , Cromossomos Sexuais/genética , Aves Canoras/genética
9.
PLoS One ; 15(4): e0231324, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267867

RESUMO

Ctenidae represents one of the most representative spider families in the tropical forests of Brazil. Its largest genus, Ctenus, has approximately 220 species out of the more than 520 Ctenidae species described, and several authors consider it polyphyletic. Chromosomal data are only available for four species of Ctenus, representing a large gap in the cytogenetic knowledge about the group. This study provided cytogenetic data on two Ctenus species and one Guasuctenus (previously described as Ctenus). All showed 2n♂ = 28 (26+X1X20). Guasuctenus longipes presented two chromosome pairs containing 18S rDNA genes and C. medius, however C. ornatus showed only one chromosome pair with the 18S rDNA gene. Hybridization data using histone H3 probe indicated specific profiles: histone H3 genes were found in one chromosome pair in G. longipes, in three pairs in C. medius, and in four pairs in C. ornatus. Furthermore, supernumerary chromosomes were identified in C. ornatus presenting a meiotic behavior similar to that of sex chromosomes; and a trivalent was found in C. medius, formed by the association of one sex chromosome and an autosomal bivalent, indicating the importance of these events for the diversification of sex chromosomes in spiders. The C-banding pattern was similar between C. medius and C. ornatus with regard to the number and locations of heterochromatic bands, suggesting that heterochromatin amplification and dispersion, affect karyotypic evolution in the genus. Cytogenetic data showed similarity between C. medius and C. ornatus, and differentiation of G. longipes congruent with morphological data. Moreover, although more comparative analyses are needed to specify composition of the dispersed heterochromatin in Ctenus, the mapping of heterochromatic bands provided insights about the evolution of the karyotypes in this genus.


Assuntos
Evolução Molecular , Heterocromatina/genética , Histonas/genética , RNA Ribossômico 18S/genética , Aranhas/genética , Animais , Mapeamento Cromossômico , Feminino , Heterocromatina/metabolismo , Hibridização in Situ Fluorescente , Cariótipo , Masculino , Meiose , Cromossomos Sexuais/genética
10.
PLoS One ; 15(4): e0230930, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267870

RESUMO

Human epidemiological studies have shown that paternal aging as one of the risk factors for neurodevelopmental disorders, such as autism, in offspring. A recent study has suggested that factors other than de novo mutations due to aging can influence the biology of offspring. Here, we focused on epigenetic alterations in sperm that can influence developmental programs in offspring. In this study, we qualitatively and semiquantitatively evaluated histone modification patterns in male germline cells throughout spermatogenesis based on immunostaining of testes taken from young (3 months old) and aged (12 months old) mice. Although localization patterns were not obviously changed between young and aged testes, some histone modification showed differences in their intensity. Among histone modifications that repress gene expression, histone H3 lysine 9 trimethylation (H3K9me3) was decreased in the male germline cells of the aged testis, while H3K27me2/3 was increased. The intensity of H3K27 acetylation (ac), an active mark, was lower/higher depending on the stages in the aged testis. Interestingly, H3K27ac was detected on the putative sex chromosomes of round spermatids, while other chromosomes were occupied by a repressive mark, H3K27me3. Among other histone modifications that activate gene expression, H3K4me2 was drastically decreased in the male germline cells of the aged testis. In contrast, H3K79me3 was increased in M-phase spermatocytes, where it accumulates on the sex chromosomes. Therefore, aging induced alterations in the amount of histone modifications and in the differences of patterns for each modification. Moreover, histone modifications on the sex chromosomes and on other chromosomes seems to be differentially regulated by aging. These findings will help elucidate the epigenetic mechanisms underlying the influence of paternal aging on offspring development.


Assuntos
Histonas/genética , Meiose/genética , Espermatócitos/fisiologia , Espermatogênese/genética , Testículo/fisiologia , Acetilação , Animais , Epigênese Genética/genética , Epigenômica/métodos , Expressão Gênica/genética , Código das Histonas/genética , Humanos , Lisina/genética , Masculino , Metilação , Camundongos , Processamento de Proteína Pós-Traducional/genética , Cromossomos Sexuais/genética , Espermátides/fisiologia
11.
Cytogenet Genome Res ; 160(3): 141-147, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32146462

RESUMO

Most eukaryotic genomes contain substantial portions of repetitive DNA sequences. These are located primarily in highly compacted heterochromatin and, in many cases, are one of the most abundant components of the sex chromosomes. In this sense, the anuran Proceratophrys boiei represents an interesting model for analyses on repetitive sequences by means of cytogenetic techniques, since it has a karyotype with large blocks of heterochromatin and a ZZ/ZW sex chromosome system. The present study describes, for the first time, families of satellite DNA (satDNA) in the frog P. boiei. Its genome size was estimated at 1.6 Gb, of which 41% correspond to repetitive sequences, including satDNAs, rDNAs, transposable elements, and other elements characterized as non-repetitive. The satDNAs were mapped by FISH in the centromeric and pericentromeric regions of all chromosomes, suggesting a possible involvement of these sequences in centromere function. SatDNAs are also present in the W sex chromosome, occupying the entire heterochromatic area, indicating a probable contribution of this class of repetitive DNA to the differentiation of the sex chromosomes in this species. This study is a valuable contribution to the existing knowledge on repetitive sequences in amphibians. We show the presence of repetitive DNAs, especially satDNAs, in the genome of P. boiei that might be of relevance in genome organization and regulation, setting the stage for a deeper functional genome analysis of Proceratophrys.


Assuntos
Anuros/genética , DNA Satélite/genética , Genoma/genética , Cromossomos Sexuais/genética , Animais , Centrômero/genética , Evolução Molecular , Heterocromatina/genética , Hibridização in Situ Fluorescente , Filogenia , Sequências Repetitivas de Ácido Nucleico/genética , Análise de Sequência de DNA
12.
Sci Rep ; 10(1): 4276, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32152354

RESUMO

Turtles demonstrate variability in sex determination and, hence, constitute an excellent model for the evolution of sex chromosomes. Notably, the sex determination of the freshwater turtles from the family Chelidae, a species-rich group with wide geographical distribution in the southern hemisphere, is still poorly explored. Here we documented the presence of an XX/XY sex determination system in seven species of the Australasian chelid genera Chelodina, Emydura, and Elseya by conventional (karyogram reconstruction, C-banding) and molecular cytogenetic methods (comparative genome hybridization, in situ hybridization with probes specific for GATA microsatellite motif, the rDNA loci, and the telomeric repeats). The sex chromosomes are microchromosomes in all examined species of the genus Chelodina. In contrast, the sex chromosomes are the 4th largest pair of macrochromosomes in the genera Emydura and Elseya. Their X chromosomes are submetacentric, while their Y chromosomes are metacentric. The chelid Y chromosomes contain a substantial male-specific genomic region with an accumulation of the GATA microsatellite motif, and occasionally, of the rDNA loci and telomeric repeats. Despite morphological differences between sex chromosomes, we conclude that male heterogamety was likely already present in the common ancestor of Chelodina, Emydura and Elseya in the Mesozoic period.


Assuntos
Evolução Molecular , Genoma , Cromossomos Sexuais/genética , Cromossomo X/genética , Cromossomo Y/genética , Animais , Feminino , Cariótipo , Masculino , Repetições de Microssatélites , Processos de Determinação Sexual , Tartarugas
13.
Evolution ; 74(4): 793-794, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32196651

RESUMO

What evolutionary processes shaped the genomic landscape of differentiation in Selasphorus hummingbirds? Battey shows that the islands of differentiation on the Z chromosome are most likely the outcome of linked selection. Furthermore, these islands might contain barrier loci that contribute to reproductive isolation between these hybridizing hummingbirds.


Assuntos
Ilhas Genômicas , Seleção Genética , Animais , Genoma , Isolamento Reprodutivo , Cromossomos Sexuais/genética
14.
Sci Rep ; 10(1): 2170, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034231

RESUMO

The human X and Y chromosomes evolved from a pair of autosomes approximately 180 million years ago. Despite their shared evolutionary origin, extensive genetic decay has resulted in the human Y chromosome losing 97% of its ancestral genes while gene content and order remain highly conserved on the X chromosome. Five 'stratification' events, most likely inversions, reduced the Y chromosome's ability to recombine with the X chromosome across the majority of its length and subjected its genes to the erosive forces associated with reduced recombination. The remaining functional genes are ubiquitously expressed, functionally coherent, dosage-sensitive genes, or have evolved male-specific functionality. It is unknown, however, whether functional specialization is a degenerative phenomenon unique to sex chromosomes, or if it conveys a potential selective advantage aside from sexual antagonism. We examined the evolution of mammalian orthologs to determine if the selective forces that led to the degeneration of the Y chromosome are unique in the genome. The results of our study suggest these forces are not exclusive to the Y chromosome, and chromosomal degeneration may have occurred throughout our evolutionary history. The reduction of recombination could additionally result in rapid fixation through isolation of specialized functions resulting in a cost-benefit relationship during times of intense selective pressure.


Assuntos
Evolução Molecular , Cromossomos Sexuais/genética , Animais , Bovinos , Galinhas , Cães , Humanos , Camundongos , Gambás , Primatas , Ratos , Recombinação Genética , Seleção Genética
16.
PLoS Genet ; 16(2): e1008566, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32069274

RESUMO

Most angiosperms bear hermaphroditic flowers, but a few species have evolved outcrossing strategies, such as dioecy, the presence of separate male and female individuals. We previously investigated the mechanisms underlying dioecy in diploid persimmon (D. lotus) and found that male flowers are specified by repression of the autosomal gene MeGI by its paralog, the Y-encoded pseudo-gene OGI. This mechanism is thought to be lineage-specific, but its evolutionary path remains unknown. Here, we developed a full draft of the diploid persimmon genome (D. lotus), which revealed a lineage-specific whole-genome duplication event and provided information on the architecture of the Y chromosome. We also identified three paralogs, MeGI, OGI and newly identified Sister of MeGI (SiMeGI). Evolutionary analysis suggested that MeGI underwent adaptive evolution after the whole-genome duplication event. Transformation of tobacco plants with MeGI and SiMeGI revealed that MeGI specifically acquired a new function as a repressor of male organ development, while SiMeGI presumably maintained the original function. Later, a segmental duplication event spawned MeGI's regulator OGI on the Y-chromosome, completing the path leading to dioecy, and probably initiating the formation of the Y-chromosome. These findings exemplify how duplication events can provide flexible genetic material available to help respond to varying environments and provide interesting parallels for our understanding of the mechanisms underlying the transition into dieocy in plants.


Assuntos
Diospyros/genética , Evolução Molecular , Genoma de Planta/genética , Processos de Determinação Sexual , Cromossomos de Plantas/genética , Diploide , Flores/genética , Filogenia , Cromossomos Sexuais/genética
17.
PLoS Biol ; 18(2): e3000610, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32108180

RESUMO

Neo-sex chromosomes are found in many taxa, but the forces driving their emergence and spread are poorly understood. The female-specific neo-W chromosome of the African monarch (or queen) butterfly Danaus chrysippus presents an intriguing case study because it is restricted to a single 'contact zone' population, involves a putative colour patterning supergene, and co-occurs with infection by the male-killing endosymbiont Spiroplasma. We investigated the origin and evolution of this system using whole genome sequencing. We first identify the 'BC supergene', a broad region of suppressed recombination across nearly half a chromosome, which links two colour patterning loci. Association analysis suggests that the genes yellow and arrow in this region control the forewing colour pattern differences between D. chrysippus subspecies. We then show that the same chromosome has recently formed a neo-W that has spread through the contact zone within approximately 2,200 years. We also assembled the genome of the male-killing Spiroplasma, and find that it shows perfect genealogical congruence with the neo-W, suggesting that the neo-W has hitchhiked to high frequency as the male-killer has spread through the population. The complete absence of female crossing-over in the Lepidoptera causes whole-chromosome hitchhiking of a single neo-W haplotype, carrying a single allele of the BC supergene and dragging multiple non-synonymous mutations to high frequency. This has created a population of infected females that all carry the same recessive colour patterning allele, making the phenotypes of each successive generation highly dependent on uninfected male immigrants. Our findings show how hitchhiking can occur between the physically unlinked genomes of host and endosymbiont, with dramatic consequences.


Assuntos
Borboletas/genética , Cromossomos de Insetos/genética , Cromossomos Sexuais/genética , Animais , Borboletas/microbiologia , Evolução Molecular , Feminino , Ligação Genética , Genoma/genética , Haplótipos , Masculino , Fenótipo , Spiroplasma/genética
18.
Cytogenet Genome Res ; 160(3): 134-140, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32092753

RESUMO

Reptiles show a remarkable diversity of sex determination mechanisms and sex chromosome systems, derived from different autosomal pairs. The origin of the ZW sex chromosomes of Lacerta agilis, a widespread Eurasian lizard species, is a matter of discussion: is it a small macrochromosome from the 11-18 group common to all lacertids, or does this species have a unique ZW pair derived from the large chromosome 5? Using independent molecular cytogenetic methods, we investigated the karyotype of L. agilis exigua from Siberia, Russia, to identify the sex chromosomes. FISH with a flow-sorted chromosome painting probe derived from L. strigata and specific to chromosomes 13, 14, and Z confirmed that the Z chromosome of L. agilis is a small macrochromosome, the same as in L. strigata. FISH with the telomeric probe showed an extensive accumulation of the telomere-like repeat in the W chromosome in agreement with previous studies, excluding the possibility that the lineages of L. agilis studied in different works could have different sex chromosome systems due to a putative intra-species polymorphism. Our results reinforce the idea of the stability of the sex chromosomes and lack of evidence for sex-chromosome turnovers in known species of Lacertidae.


Assuntos
Evolução Biológica , Lagartos/genética , Sequências Repetitivas de Ácido Nucleico/genética , Cromossomos Sexuais/genética , Animais , Hibridização in Situ Fluorescente , Federação Russa
19.
Cytogenet Genome Res ; 160(1): 38-46, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32092756

RESUMO

The repetitive DNA content of fish sex chromosomes provides valuable insights into specificities and patterns of their genetic sex determination systems. In this study, we revealed the genomic satellite DNA (satDNA) content of Megaleporinuselongatus, a Neotropical fish species with Z1Z1Z2Z2/Z1W1Z2W2 multiple sex chromosomes, through high-throughput analysis and graph-based clustering, isolating 68 satDNA families. By physically mapping these sequences in female metaphases, we discovered 15 of the most abundant satDNAs clustered in its chromosomes, 9 of which were found exclusively in the highly heterochromatic W1. This heteromorphic sex chromosome showed the highest amount of satDNA accumulations in this species. The second most abundant family, MelSat02-26, shared FISH signals with the NOR-bearing pair in similar patterns and is linked to the multiple sex chromosome system. Our results demonstrate the diverse satDNA content in M. elongatus, especially in its heteromorphic sex chromosome. Additionally, we highlighted the different accumulation patterns and distribution of these sequences across species by physically mapping these satDNAs in other Anostomidae, Megaleporinusmacrocephalus and Leporinusfriderici (a species without differentiated sex chromosomes).


Assuntos
Caraciformes/genética , DNA Satélite/genética , DNA/genética , Cromossomos Sexuais/genética , Animais , Linhagem da Célula , Mapeamento Cromossômico , Evolução Molecular , Feminino , Genoma , Genômica , Heterocromatina/metabolismo , Hibridização in Situ Fluorescente , Masculino , Metáfase , Análise de Sequência de DNA
20.
PLoS One ; 15(1): e0225392, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31917799

RESUMO

Late onset Alzheimer's disease (LOAD) is a progressive neurodegenerative disease with four well-established risk factors: age, APOE4 genotype, female chromosomal sex, and maternal history of AD. Each risk factor impacts multiple systems, making LOAD a complex systems biology challenge. To investigate interactions between LOAD risk factors, we performed multiple scale analyses, including metabolomics, transcriptomics, brain magnetic resonance imaging (MRI), and beta-amyloid assessment, in 16 months old male and female mice with humanized human APOE3 (hAPOE3) or APOE4 (hAPOE4) genes. Metabolomic analyses indicated a sex difference in plasma profile whereas APOE genotype determined brain metabolic profile. Consistent with the brain metabolome, gene and pathway-based RNA-Seq analyses of the hippocampus indicated increased expression of fatty acid/lipid metabolism related genes and pathways in both hAPOE4 males and females. Further, female transcription of fatty acid and amino acids pathways were significantly different from males. MRI based imaging analyses indicated that in multiple white matter tracts, hAPOE4 males and females exhibited lower fractional anisotropy than their hAPOE3 counterparts, suggesting a lower level of white matter integrity in hAPOE4 mice. Consistent with the brain metabolomic and transcriptomic profile of hAPOE4 carriers, beta-amyloid generation was detectable in 16-month-old male and female brains. These data provide therapeutic targets based on chromosomal sex and APOE genotype. Collectively, these data provide a framework for developing precision medicine interventions during the prodromal phase of LOAD, when the potential to reverse, prevent and delay LOAD progression is greatest.


Assuntos
Doença de Alzheimer/genética , Apolipoproteína E4/genética , Apolipoproteínas E/genética , Encéfalo/metabolismo , Idade de Início , Envelhecimento/genética , Envelhecimento/metabolismo , Envelhecimento/patologia , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Genótipo , Humanos , Imagem por Ressonância Magnética , Masculino , Metaboloma/genética , Camundongos , Camundongos Transgênicos , Caracteres Sexuais , Cromossomos Sexuais/genética , Cromossomos Sexuais/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA