Similar Datasets
Project description:The brushtail possum, Trichosurus vulpecula, is threatened in parts of its native range in Australia, but has also become a devastating mammalian pest following introduction into New Zealand from the mid 1800s. We have completed the first chromosome-level assembly of the possum genome and, using nuclear and mitochondrial analyses, traced southern New Zealand possums to distinct Tasmanian and mainland Australian subspecies, which have subsequently hybridised. This admixture is reflected in high levels of genetic diversity within New Zealand populations despite a founding bottleneck. Functional genomics revealed unique adaptations to altricial birth and extending weaning, including novel chemo-sensory genes, and at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We found that reprogramming of possum germline imprints and the wider epigenome was similar to eutherian mammals, except onset occurs after birth. Together, our data and analysis is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits such as germline methylation erasure and genomic imprinting.
2022-11-29 | GSE218734 | GEO
Project description:The brushtail possum, Trichosurus vulpecula, is threatened in parts of its native range in Australia, but has also become a devastating mammalian pest following introduction into New Zealand from the mid 1800s. We have completed the first chromosome-level assembly of the possum genome and, using nuclear and mitochondrial analyses, traced southern New Zealand possums to distinct Tasmanian and mainland Australian subspecies, which have subsequently hybridised. This admixture is reflected in high levels of genetic diversity within New Zealand populations despite a founding bottleneck. Functional genomics revealed unique adaptations to altricial birth and extending weaning, including novel chemo-sensory genes, and at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We found that reprogramming of possum germline imprints and the wider epigenome was similar to eutherian mammals, except onset occurs after birth. Together, our data and analysis is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits such as germline methylation erasure and genomic imprinting.
2022-11-29 | GSE218695 | GEO
Project description:Genomic imprinting characterizes genes with a monoallelic expression, which is dependent on the parental origin of each allele. Approximately 150 imprinted genes are known to date, in humans and mice but, though computational searches have tried to extract intrinsic characteristics of these genes to identify new ones, the existing list is probably far from being comprehensive. We used a high-throughput strategy by diverting the classical use of genotyping microarrays to compare the genotypes of mRNA/cDNA vs. genomic DNA to identify new genes presenting monoallelic expression, starting from human placental material. After filtering of data, we obtained a list of 1,082 putative candidate monoallelic SNPs located in more than one hundred candidate genes. Among these, we found known imprinted genes, such as IPW, GRB10, INPP5F and ZNF597, which contribute to validate the approach. We also explored some likely candidates of our list and identified seven new imprinted genes, including ZFAT, ZFAT-AS1, GLIS3, NTM, MAGI2, ZC3H12Cand LIN28B, four of which encode zinc finger transcription factors. They are, however, not imprinted in the mouse placenta, except for Magi2. We analyzed in more details the ZFAT gene, which is paternally expressed in the placenta (as ZFAT-AS1, a non-coding antisense RNA) but biallelic in other tissues. The ZFAT protein is expressed in endothelial cells, as well as in syncytiotrophoblasts. The expression of this gene is, moreover, downregulated in placentas from complicated pregnancies. With this work we increase by about 10% the number of known imprinted genes in humans.
| S-EPMC3466192 | biostudies-literature
Project description:The house mouse (Mus musculus) provides a fascinating system for studying both the genomic basis of reproductive isolation, and the patterns of human-mediated dispersal. New Zealand has a complex history of mouse invasions, and the living descendants of these invaders have genetic ancestry from all three subspecies, although most are primarily descended from M. m. domesticus. We used the GigaMUGA genotyping array (approximately 135?000 loci) to describe the genomic ancestry of 161 mice, sampled from 34 locations from across New Zealand (and one Australian city-Sydney). Of these, two populations, one in the south of the South Island, and one on Chatham Island, showed complete mitochondrial lineage capture, featuring two different lineages of M. m. castaneus mitochondrial DNA but with only M. m. domesticus nuclear ancestry detectable. Mice in the northern and southern parts of the North Island had small traces (approx. 2-3%) of M. m. castaneus nuclear ancestry, and mice in the upper South Island had approximately 7-8% M. m. musculus nuclear ancestry including some Y-chromosomal ancestry-though no detectable M. m. musculus mitochondrial ancestry. This is the most thorough genomic study of introduced populations of house mice yet conducted, and will have relevance to studies of the isolation mechanisms separating subspecies of mice.
| S-EPMC5792881 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-09-01 | E-GEOD-56781 | biostudies-arrayexpress
Project description:Imprinted genes are critical for normal human growth and neurodevelopment. They are characterized by differentially methylated regions (DMRs) of DNA that confer parent of origin-specific transcription. We developed a new strategy to identify imprinted gene-associated DMRs. Using genome-wide methylation profiling of sodium bisulfite modified DNA from normal human tissues of biparental origin, candidate DMRs were identified by selecting CpGs with methylation levels consistent with putative allelic differential methylation. In parallel, the methylation profiles of tissues of uniparental origin, i.e., paternally-derived androgenetic complete hydatidiform moles (AnCHMs), and maternally-derived mature cystic ovarian teratoma (MCT), were examined and then used to identify CpGs with parent of origin-specific DNA methylation. With this approach, we found known DMRs associated with imprinted genomic regions as well as new DMRs for known imprinted genes, NAP1L5 and ZNF597, and novel candidate imprinted genes. The paternally methylated DMR for one candidate, AXL, a receptor tyrosine kinase, was also validated in experiments with mouse embryos that demonstrated Axl was expressed preferentially from the maternal allele in a DNA methylation-dependent manner.
| S-EPMC3044860 | biostudies-other
Project description:Recent sequencing of Plasmodium vivax field isolates and monkey-adapted strains enabled characterization of SNPs throughout the genome. These analyses relied on mapping short reads onto the P. vivax reference genome that was generated using DNA from the monkey-adapted strain Salvador I. Any genomic locus deleted in this strain would be lacking in the reference genome sequence and missed in previous analyses. Here, we report de novo assembly of a P. vivax field isolate genome. Out of 2,857 assembled contigs, we identify 362 contigs, each containing more than 5 kb of contiguous DNA sequences absent from the reference genome sequence. These novel P. vivax DNA sequences account for 3.8 million nucleotides and contain 792 predicted genes. Most of these contigs contain members of multigene families and likely originate from telomeric regions. Interestingly, we identify two contigs containing predicted protein coding genes similar to known Plasmodium red blood cell invasion proteins. One gene encodes the reticulocyte-binding protein gene orthologous to P. cynomolgi RBP2e and P. knowlesi NBPXb. The second gene harbors all the hallmarks of a Plasmodium erythrocyte-binding protein, including conserved Duffy-binding like and C-terminus cysteine-rich domains. Phylogenetic analysis shows that this novel gene clusters separately from all known Plasmodium Duffy-binding protein genes. Additional analyses showing that this gene is present in most P. vivax genomes and transcribed in blood-stage parasites suggest that P. vivax red blood cell invasion mechanisms may be more complex than currently understood. The strategy employed here complements previous genomic analyses and takes full advantage of next-generation sequencing data to provide a comprehensive characterization of genetic variations in this important malaria parasite. Further analyses of the novel protein coding genes discovered through de novo assembly have the potential to identify genes that influence key aspects of P. vivax biology, including alternative mechanisms of human erythrocyte invasion.
| S-EPMC3854868 | biostudies-literature
Project description:Saccharomyces cerevisiae is extensively utilized for commercial fermentation, and is also an important biological model; however, its ecology has only recently begun to be understood. Through the use of whole-genome sequencing, the species has been characterized into a number of distinct subpopulations, defined by geographical ranges and industrial uses. Here, the whole-genome sequences of 104 New Zealand (NZ) S. cerevisiae strains, including 52 novel genomes, are analyzed alongside 450 published sequences derived from various global locations. The impact of S. cerevisiae novel range expansion into NZ was investigated and these analyses reveal the positioning of NZ strains as a subgroup to the predominantly European/wine clade. A number of genomic differences with the European group correlate with range expansion into NZ, including 18 highly enriched single-nucleotide polymorphism (SNPs) and novel Ty1/2 insertions. While it is not possible to categorically determine if any genetic differences are due to stochastic process or the operations of natural selection, we suggest that the observation of NZ-specific copy number increases of four sugar transporter genes in the HXT family may reasonably represent an adaptation in the NZ S. cerevisiae subpopulation, and this correlates with the observations of copy number changes during adaptation in small-scale experimental evolution studies.
| S-EPMC7849907 | biostudies-literature
Project description:The coelacanth is one of the nearest living relatives of tetrapods. However, a teleost species such as zebrafish or Fugu is typically used as the outgroup in current tetrapod comparative sequence analyses. Such studies are complicated by the fact that teleost genomes have undergone a whole-genome duplication event, as well as individual gene-duplication events. Here, we demonstrate the value of coelacanth genome sequence by complete sequencing and analysis of the protocadherin gene cluster of the Indonesian coelacanth, Latimeria menadoensis. We found that coelacanth has 49 protocadherin cluster genes organized in the same three ordered subclusters, alpha, beta, and gamma, as the 54 protocadherin cluster genes in human. In contrast, whole-genome and tandem duplications have generated two zebrafish protocadherin clusters comprised of at least 97 genes. Additionally, zebrafish protocadherins are far more prone to homogenizing gene conversion events than coelacanth protocadherins, suggesting that recombination- and duplication-driven plasticity may be a feature of teleost genomes. Our results indicate that coelacanth provides the ideal outgroup sequence against which tetrapod genomes can be measured. We therefore present L. menadoensis as a candidate for whole-genome sequencing.
| S-EPMC534663 | biostudies-literature
Project description:A characteristic of imprinted genes is that the maternal and paternal alleles show differences in methylation. To perform a genome-wide screen for novel imprinted loci, we applied methylation-sensitive representational difference analysis (Me-RDA) to parthenogenetic mouse embryos, to identify differentially methylated regions (DMRs) methylated specifically on the maternal allele. We isolated a total of 26 distinct clones from known and novel DMRs and identified three novel imprinted genes. Nap1l5 is located on proximal chromosome 6 and encodes a protein with homology with nucleosome assembly proteins (NAPs); it has tissue-specific imprinting with expression from the paternal allele. We identified two DMRs on chromosome 15, a chromosome that was not thought to contain imprinted loci, and demonstrated that each is associated with a paternally expressed transcript. Peg13 gives rise to a noncoding RNA that is highly expressed in the brain and imprinted in all tissues examined. A DMR was also identified at the chromosome 15 Slc38a4 gene, which encodes a system A amino acid transporter; we show that Slc38a4 is imprinted in a tissue-specific manner. Interestingly, two of the three novel genes identified in this screen are located within the introns of other genes; their identification indicates that such "microimprinted" domains may be more common than previously thought.
| S-EPMC430166 | biostudies-literature