| 1. |
- Alfoeldi, Jessica, et al.
(författare)
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The genome of the green anole lizard and a comparative analysis with birds and mammals
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 477:7366, s. 587-591
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of the amniotic egg was one of the great evolutionary innovations in the history of life, freeing vertebrates from an obligatory connection to water and thus permitting the conquest of terrestrial environments(1). Among amniotes, genome sequences are available for mammals and birds(2-4), but not for non-avian reptiles. Here we report the genome sequence of the North American green anole lizard, Anolis carolinensis. We find that A. carolinensis microchromosomes are highly syntenic with chicken microchromosomes, yet do not exhibit the high GC and low repeat content that are characteristic of avian microchromosomes(2). Also, A. carolinensis mobile elements are very young and diverse-more so than in any other sequenced amniote genome. The GC content of this lizard genome is also unusual in its homogeneity, unlike the regionally variable GC content found in mammals and birds(5). We describe and assign sequence to the previously unknown A. carolinensis X chromosome. Comparative gene analysis shows that amniote egg proteins have evolved significantly more rapidly than other proteins. An anole phylogeny resolves basal branches to illuminate the history of their repeated adaptive radiations.
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| 2. |
- Amemiya, Chris T., et al.
(författare)
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The African coelacanth genome provides insights into tetrapod evolution
- 2013
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 496:7445, s. 311-316
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.
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| 3. |
- Baumann, Martina, et al.
(författare)
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Artificially designed promoters : understanding the role of spatial features and canonical binding sites in transcription
- 2012
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Ingår i: Bioengineered Bugs. - : Informa UK Limited. - 1949-1018 .- 1949-1026. ; 3:2, s. 120-123
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Tidskriftsartikel (refereegranskat)abstract
- The promoter is a key element in gene transcription and regulation. We previously reported that artificial sequences rich in the dinucleotide CpG are sufficient to drive expression in vitro in mammalian cell lines, without requiring canonical binding sites for transcription factor proteins. Here, we report that introducing a promoter organization that alternates in CpGs and regions rich in A and T further increases expression strength, as well as how insertion of specific binding sites makes such sequences respond to induced levels of the transcription factor NFκB. Our findings further contribute to the mechanistic understanding of promoters, as well as how these sequences might be shaped by evolutionary pressure in living organisms.
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| 4. |
- Bellone, Rebecca R, et al.
(författare)
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Fine-mapping and mutation analysis of TRPM1 : a candidate gene for leopard complex (LP) spotting and congenital stationary night blindness in horses
- 2010
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Ingår i: Briefings in Functional Genomics & Proteomics. - : Oxford University Press (OUP). - 1473-9550 .- 1477-4062 .- 2041-2649 .- 2041-2657. ; 9:3, s. 193-207
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Tidskriftsartikel (refereegranskat)abstract
- Leopard Complex spotting occurs in several breeds of horses and is caused by an incompletely dominant allele (LP). Homozygosity for LP is also associated with congenital stationary night blindness (CSNB) in Appaloosa horses. Previously, LP was mapped to a 6 cm region on ECA1 containing the candidate gene TRPM1 (Transient Receptor Potential Cation Channel, Subfamily M, Member 1) and decreased expression of this gene, measured by qRT-PCR, was identified as the likely cause of both spotting and ocular phenotypes. This study describes investigations for a mutation causing or associated with the Leopard Complex and CSNB phenotype in horses. Re-sequencing of the gene and associated splice sites within the 105 624 bp genomic region of TRPM1 led to the discovery of 18 SNPs. Most of the SNPs did not have a predictive value for the presence of LP. However, one SNP (ECA1:108,249,293 C>T) found within intron 11 had a strong (P < 0.0005), but not complete, association with LP and CSNB and thus is a good marker but unlikely to be causative. To further localize the association, 70 SNPs spanning over two Mb including the TRPM1 gene were genotyped in 192 horses from three different breeds segregating for LP. A single 173 kb haplotype associated with LP and CSNB (ECA1: 108,197,355- 108,370,150) was identified. Illumina sequencing of 300 kb surrounding this haplotype revealed 57 SNP variants. Based on their localization within expressed sequences or regions of high sequence conservation across mammals, six of these SNPs were considered to be the most likely candidate mutations. While the precise function of TRPM1 remains to be elucidated, this work solidifies its functional role in both pigmentation and night vision. Further, this work has identified several potential regulatory elements of the TRPM1 gene that should be investigated further in this and other species.
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| 5. |
- Ching, Yung-Hao, et al.
(författare)
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High resolution mapping and positional cloning of ENU-induced mutations in the Rw region of mouse chromosome 5
- 2010
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Ingår i: BMC Genetics. - : Springer Science and Business Media LLC. - 1471-2156. ; 11, s. 106-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Forward genetic screens in mice provide an unbiased means to identify genes and other functional genetic elements in the genome. Previously, a large scale ENU mutagenesis screen was conducted to query the functional content of a similar to 50 Mb region of the mouse genome on proximal Chr 5. The majority of phenotypic mutants recovered were embryonic lethals. Results: We report the high resolution genetic mapping, complementation analyses, and positional cloning of mutations in the target region. The collection of identified alleles include several with known or presumed functions for which no mutant models have been reported (Tbc1d14, Nol14, Tyms, Cad, Fbxl5, Haus3), and mutations in genes we or others previously reported (Tapt1, Rest, Ugdh, Paxip1, Hmx1, Otoe, Nsun7). We also confirmed the causative nature of a homeotic mutation with a targeted allele, mapped a lethal mutation to a large gene desert, and localized a spermiogenesis mutation to a region in which no annotated genes have coding mutations. The mutation in Tbc1d14 provides the first implication of a critical developmental role for RAB-GAP-mediated protein transport in early embryogenesis. Conclusion: This collection of alleles contributes to the goal of assigning biological functions to all known genes, as well as identifying novel functional elements that would be missed by reverse genetic approaches.
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| 6. |
- Fairfield, Heather, et al.
(författare)
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Mutation discovery in mice by whole exome sequencing
- 2011
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 12:9, s. R86-
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Tidskriftsartikel (refereegranskat)abstract
- We report the development and optimization of reagents for in-solution, hybridization-based capture of the mouse exome. By validating this approach in a multiple inbred strains and in novel mutant strains, we show that whole exome sequencing is a robust approach for discovery of putative mutations, irrespective of strain background. We found strong candidate mutations for the majority of mutant exomes sequenced, including new models of orofacial clefting, urogenital dysmorphology, kyphosis and autoimmune hepatitis.
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| 7. |
- Grabherr, Manfred G., et al.
(författare)
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Exploiting Nucleotide Composition to Engineer Promoters
- 2011
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Ingår i: PLoS One. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5, s. e20136-
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Tidskriftsartikel (refereegranskat)abstract
- The choice of promoter is a critical step in optimizing the efficiency and stability of recombinant protein production in mammalian cell lines. Artificial promoters that provide stable expression across cell lines and can be designed to the desired strength constitute an alternative to the use of viral promoters. Here, we show how the nucleotide characteristics of highly active human promoters can be modelled via the genome-wide frequency distribution of short motifs: by overlapping motifs that occur infrequently in the genome, we constructed contiguous sequence that is rich in GC and CpGs, both features of known promoters, but lacking homology to real promoters. We show that snippets from this sequence, at 100 base pairs or longer, drive gene expression in vitro in a number of mammalian cells, and are thus candidates for use in protein production. We further show that expression is driven by the general transcription factors TFIIB and TFIID, both being ubiquitously present across cell types, which results in less tissue-and species-specific regulation compared to the viral promoter SV40. We lastly found that the strength of a promoter can be tuned up and down by modulating the counts of GC and CpGs in localized regions. These results constitute a "proof-of-concept" for custom-designing promoters that are suitable for biotechnological and medical applications.
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| 8. |
- Grabherr, Manfred G, et al.
(författare)
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Full-length transcriptome assembly from RNA-Seq data without a reference genome
- 2011
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Ingår i: Nature Biotechnology. - : Springer Science and Business Media LLC. - 1087-0156 .- 1546-1696. ; 29:7, s. 644-652
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Tidskriftsartikel (refereegranskat)abstract
- Massively parallel sequencing of cDNA has enabled deep and efficient probing of transcriptomes. Current approaches for transcript reconstruction from such data often rely on aligning reads to a reference genome, and are thus unsuitable for samples with a partial or missing reference genome. Here we present the Trinity method for de novo assembly of full-length transcripts and evaluate it on samples from fission yeast, mouse and whitefly, whose reference genome is not yet available. By efficiently constructing and analyzing sets of de Bruijn graphs, Trinity fully reconstructs a large fraction of transcripts, including alternatively spliced isoforms and transcripts from recently duplicated genes. Compared with other de novo transcriptome assemblers, Trinity recovers more full-length transcripts across a broad range of expression levels, with a sensitivity similar to methods that rely on genome alignments. Our approach provides a unified solution for transcriptome reconstruction in any sample, especially in the absence of a reference genome.
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| 9. |
- Grabherr, Manfred G, et al.
(författare)
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Genome sequencing and assembly
- 2011
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Ingår i: Methods in molecular biology (Clifton, N.J.). - Totowa, NJ : Humana Press. - 1940-6029. ; 722, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Decoding the genome sequence is becoming a fundamental tool for molecular, genetic, and genomic studies. This chapter reviews the history of DNA sequencing and technical principles of different sequencing platforms, and compares the strengths and weaknesses of different techniques for high-throughput genome sequencing applications are compared. It also covers brief descriptions on genome assembly and its validation.
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| 10. |
- Grabherr, Manfred G, et al.
(författare)
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Genome-wide synteny through highly sensitive sequence alignment : Satsuma
- 2010
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 26:9, s. 1145-1151
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Tidskriftsartikel (refereegranskat)abstract
- MOTIVATION: Comparative genomics heavily relies on alignments of large and often complex DNA sequences. From an engineering perspective, the problem here is to provide maximum sensitivity (to find all there is to find), specificity (to only find real homology) and speed (to accommodate the billions of base pairs of vertebrate genomes). RESULTS: Satsuma addresses all three issues through novel strategies: (i) cross-correlation, implemented via fast Fourier transform; (ii) a match scoring scheme that eliminates almost all false hits; and (iii) an asynchronous 'battleship'-like search that allows for aligning two entire fish genomes (470 and 217 Mb) in 120 CPU hours using 15 processors on a single machine. AVAILABILITY: Satsuma is part of the Spines software package, implemented in C++ on Linux. The latest version of Spines can be freely downloaded under the LGPL license from http://www.broadinstitute.org/science/programs/genome-biology/spines/.
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