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1.  Oil palm genome sequence reveals divergence of interfertile species in old and new worlds 
Nature  2013;500(7462):335-339.
Oil palm is the most productive oil-bearing crop. Planted on only 5% of the total vegetable oil acreage, palm oil accounts for 33% of vegetable oil, and 45% of edible oil worldwide, but increased cultivation competes with dwindling rainforest reserves. We report the 1.8 gigabase (Gb) genome sequence of the African oil palm Elaeis guineensis, the predominant source of worldwide oil production. 1.535 Gb of assembled sequence and transcriptome data from 30 tissue types were used to predict at least 34,802 genes, including oil biosynthesis genes and homologues of WRINKLED1 (WRI1), and other transcriptional regulators1, which are highly expressed in the kernel. We also report the draft sequence of the S. American oil palm Elaeis oleifera, which has the same number of chromosomes (2n=32) and produces fertile interspecific hybrids with E. guineensis2, but appears to have diverged in the new world. Segmental duplications of chromosome arms define the palaeotetraploid origin of palm trees. The oil palm sequence enables the discovery of genes for important traits as well as somaclonal epigenetic alterations which restrict the use of clones in commercial plantings3, and thus helps achieve sustainability for biofuels and edible oils, reducing the rainforest footprint of this tropical plantation crop.
PMCID: PMC3929164  PMID: 23883927
Nature genetics  2013;45(3):242-252.
The genetic basis of hypodiploid acute lymphoblastic leukemia (ALL), a subtype of ALL characterized by aneuploidy and poor outcome, is unknown. Genomic profiling of 124 hypodiploid ALL cases, including whole genome and exome sequencing of 40 cases, identified two subtypes that differ in severity of aneuploidy, transcriptional profile and submicroscopic genetic alterations. Near haploid cases with 24–31 chromosomes harbor alterations targeting receptor tyrosine kinase- and Ras signaling (71%) and the lymphoid transcription factor IKZF3 (AIOLOS; 13%). In contrast, low hypodiploid ALL with 32–39 chromosomes are characterized by TP53 alterations (91.2%) which are commonly present in non-tumor cells, and alterations of IKZF2 (HELIOS; 53%) and RB1 (41%). Both near haploid and low hypodiploid tumors exhibit activation of Ras- and PI3K signaling pathways, and are sensitive to PI3K inhibitors, indicating that these drugs should be explored as a new therapeutic strategy for this aggressive form of leukemia.
PMCID: PMC3919793  PMID: 23334668
3.  Integration of Sequence Data from a Consanguineous Family with Genetic Data from an Outbred Population Identifies PLB1 as a Candidate Rheumatoid Arthritis Risk Gene 
PLoS ONE  2014;9(2):e87645.
Integrating genetic data from families with highly penetrant forms of disease together with genetic data from outbred populations represents a promising strategy to uncover the complete frequency spectrum of risk alleles for complex traits such as rheumatoid arthritis (RA). Here, we demonstrate that rare, low-frequency and common alleles at one gene locus, phospholipase B1 (PLB1), might contribute to risk of RA in a 4-generation consanguineous pedigree (Middle Eastern ancestry) and also in unrelated individuals from the general population (European ancestry). Through identity-by-descent (IBD) mapping and whole-exome sequencing, we identified a non-synonymous c.2263G>C (p.G755R) mutation at the PLB1 gene on 2q23, which significantly co-segregated with RA in family members with a dominant mode of inheritance (P = 0.009). We further evaluated PLB1 variants and risk of RA using a GWAS meta-analysis of 8,875 RA cases and 29,367 controls of European ancestry. We identified significant contributions of two independent non-coding variants near PLB1 with risk of RA (rs116018341 [MAF = 0.042] and rs116541814 [MAF = 0.021], combined P = 3.2×10−6). Finally, we performed deep exon sequencing of PLB1 in 1,088 RA cases and 1,088 controls (European ancestry), and identified suggestive dispersion of rare protein-coding variant frequencies between cases and controls (P = 0.049 for C-alpha test and P = 0.055 for SKAT). Together, these data suggest that PLB1 is a candidate risk gene for RA. Future studies to characterize the full spectrum of genetic risk in the PLB1 genetic locus are warranted.
PMCID: PMC3919745  PMID: 24520335
4.  RB1 gene inactivation by chromothripsis in human retinoblastoma 
Oncotarget  2014;5(2):438-450.
Retinoblastoma is a rare childhood cancer of the developing retina. Most retinoblastomas initiate with biallelic inactivation of the RB1 gene through diverse mechanisms including point mutations, nucleotide insertions, deletions, loss of heterozygosity and promoter hypermethylation. Recently, a novel mechanism of retinoblastoma initiation was proposed. Gallie and colleagues discovered that a small proportion of retinoblastomas lack RB1 mutations and had MYCN amplification [1]. In this study, we identifed recurrent chromosomal, regional and focal genomic lesions in 94 primary retinoblastomas with their matched normal DNA using SNP 6.0 chips. We also analyzed the RB1 gene mutations and compared the mechanism of RB1 inactivation to the recurrent copy number variations in the retinoblastoma genome. In addition to the previously described focal amplification of MYCN and deletions in RB1 and BCOR, we also identifed recurrent focal amplification of OTX2, a transcription factor required for retinal photoreceptor development. We identifed 10 retinoblastomas in our cohort that lacked RB1 point mutations or indels. We performed whole genome sequencing on those 10 tumors and their corresponding germline DNA. In one of the tumors, the RB1 gene was unaltered, the MYCN gene was amplified and RB1 protein was expressed in the nuclei of the tumor cells. In addition, several tumors had complex patterns of structural variations and we identified 3 tumors with chromothripsis at the RB1 locus. This is the first report of chromothripsis as a mechanism for RB1 gene inactivation in cancer.
PMCID: PMC3964219  PMID: 24509483
chromothripsis; retinoblastoma; RB1; MYCN
5.  Re-sequencing Expands Our Understanding of the Phenotypic Impact of Variants at GWAS Loci 
PLoS Genetics  2014;10(1):e1004147.
Genome-wide association studies (GWAS) have identified >500 common variants associated with quantitative metabolic traits, but in aggregate such variants explain at most 20–30% of the heritable component of population variation in these traits. To further investigate the impact of genotypic variation on metabolic traits, we conducted re-sequencing studies in >6,000 members of a Finnish population cohort (The Northern Finland Birth Cohort of 1966 [NFBC]) and a type 2 diabetes case-control sample (The Finland-United States Investigation of NIDDM Genetics [FUSION] study). By sequencing the coding sequence and 5′ and 3′ untranslated regions of 78 genes at 17 GWAS loci associated with one or more of six metabolic traits (serum levels of fasting HDL-C, LDL-C, total cholesterol, triglycerides, plasma glucose, and insulin), and conducting both single-variant and gene-level association tests, we obtained a more complete understanding of phenotype-genotype associations at eight of these loci. At all eight of these loci, the identification of new associations provides significant evidence for multiple genetic signals to one or more phenotypes, and at two loci, in the genes ABCA1 and CETP, we found significant gene-level evidence of association to non-synonymous variants with MAF<1%. Additionally, two potentially deleterious variants that demonstrated significant associations (rs138726309, a missense variant in G6PC2, and rs28933094, a missense variant in LIPC) were considerably more common in these Finnish samples than in European reference populations, supporting our prior hypothesis that deleterious variants could attain high frequencies in this isolated population, likely due to the effects of population bottlenecks. Our results highlight the value of large, well-phenotyped samples for rare-variant association analysis, and the challenge of evaluating the phenotypic impact of such variants.
Author Summary
Abnormal serum levels of various metabolites, including measures relevant to cholesterol, other fats, and sugars, are known to be risk factors for cardiovascular disease and type 2 diabetes. Identification of the genes that play a role in generating such abnormalities could advance the development of new treatment and prevention strategies for these disorders. Investigations of common genetic variants carried out in large sets of research subjects have successfully pinpointed such genes within many regions of the human genome. However, these studies often have not led to the identification of the specific genetic variations affecting metabolic traits. To attempt to detect such causal variations, we sequenced genes in 17 genomic regions implicated in metabolic traits in >6,000 people from Finland. By conducting statistical analyses relating specific variations (individually and grouped by gene) to the measures for these metabolic traits observed in the study subjects, we added to our understanding of how genotypes affect these traits. Our findings support a long-held hypothesis that the unique history of the Finnish population provides important advantages for analyzing the relationship between genetic variations and biomedically important traits.
PMCID: PMC3907339  PMID: 24497850
6.  Endocrine-Therapy-Resistant ESR1 Variants Revealed by Genomic Characterization of Breast-Cancer-Derived Xenografts 
Cell reports  2013;4(6):10.1016/j.celrep.2013.08.022.
To characterize patient-derived xenografts (PDXs) for functional studies, we made whole-genome comparisons with originating breast cancers representative of the major intrinsic subtypes. Structural and copy number aberrations were found to be retained with high fidelity. However, at the single-nucleotide level, variable numbers of PDX-specific somatic events were documented, although they were only rarely functionally significant. Variant allele frequencies were often preserved in the PDXs, demonstrating that clonal representation can be transplantable. Estrogen-receptor-positive PDXs were associated with ESR1 ligand-binding-domain mutations, gene amplification, or an ESR1/YAP1 translocation. These events produced different endocrine-therapy-response phenotypes in human, cell line, and PDX endocrine-response studies. Hence, deeply sequenced PDX models are an important resource for the search for genome-forward treatment options and capture endocrine-drug-resistance etiologies that are not observed in standard cell lines. The originating tumor genome provides a benchmark for assessing genetic drift and clonal representation after transplantation.
PMCID: PMC3881975  PMID: 24055055
7.  Whole-genome sequencing identifies genetic alterations in pediatric low-grade gliomas 
Nature genetics  2013;45(6):602-612.
The commonest pediatric brain tumors are low-grade gliomas (LGGs). We utilized whole genome sequencing to discover multiple novel genetic alterations involving BRAF, RAF1, FGFR1, MYB, MYBL1 and genes with histone-related functions, including H3F3A and ATRX, in 39 LGGs and low-grade glioneuronal tumors (LGGNTs). Only a single non-silent somatic alteration was detected in 24/39 (62%) tumors. Intragenic duplications of the FGFR1 tyrosine kinase domain (TKD) and rearrangements of MYB were recurrent and mutually exclusive in 53% of grade II diffuse LGGs. Transplantation of Trp53-null neonatal astrocytes containing TKD-duplicated FGFR1 into brains of nude mice generated high-grade astrocytomas with short latency and 100% penetrance. TKD-duplicated FGFR1 induced FGFR1 autophosphorylation and upregulation of the MAPK/ERK and PI3K pathways, which could be blocked by specific inhibitors. Focusing on the therapeutically challenging diffuse LGGs, our study of 151 tumors has discovered genetic alterations and potential therapeutic targets across the entire range of pediatric LGGs/LGGNTs.
PMCID: PMC3727232  PMID: 23583981
8.  The Pristionchus pacificus genome provides a unique perspective on nematode lifestyle and parasitism 
Nature genetics  2008;40(10):10.1038/ng.227.
Here we present a draft genome sequence of the nematode Pristionchus pacificus, a species that is associated with beetles and is used as a model system in evolutionary biology. With 169 Mb and 23,500 predicted protein-coding genes, the P. pacificus genome is larger than those of Caenorhabditis elegans and the human parasite Brugia malayi. Compared to C. elegans, the P. pacificus genome has more genes encoding cytochrome P450 enzymes, glucosyltransferases, sulfotransferases and ABC transporters, many of which were experimentally validated. The P. pacificus genome contains genes encoding cellulase and diapausin, and cellulase activity is found in P. pacificus secretions, indicating that cellulases can be found in nematodes beyond plant parasites. The relatively higher number of detoxification and degradation enzymes in P. pacificus is consistent with its necromenic lifestyle and might represent a preadaptation for parasitism. Thus, comparative genomics analysis of three ecologically distinct nematodes offers a unique opportunity to investigate the association between genome structure and lifestyle.
PMCID: PMC3816844  PMID: 18806794
Cell  2012;150(6):1121-1134.
We report the results of whole genome and transcriptome sequencing of tumor and adjacent normal tissue samples from 17 patients with non-small cell lung carcinoma (NSCLC). We identified 3,726 point mutations and over 90 indels in the coding sequence, with an average mutation frequency more than 10-fold higher in smokers than in never-smokers. Novel alterations in genes involved in chromatic modification and DNA repair pathways were identified along with DACH1, CFTR, RELN, ABCB5, and HGF. Deep digital sequencing revealed diverse clonality patterns in both never smokers and smokers. All validated EFGR and KRAS mutations were present in the founder clones, suggesting possible roles in cancer initiation. Analysis revealed 14 fusions including ROS1 and ALK as well as novel metabolic enzymes. Cell cycle and JAK-STAT pathways are significantly altered in lung cancer along with perturbations in 54 genes that are potentially targetable with currently available drugs.
PMCID: PMC3656590  PMID: 22980976
10.  The origin and evolution of mutations in Acute Myeloid Leukemia 
Cell  2012;150(2):264-278.
Most mutations in cancer genomes are thought to be acquired after the initiating event, which may cause genomic instability, driving clonal evolution. However, for acute myeloid leukemia (AML), normal karyotypes are common, and genomic instability is unusual. To better understand clonal evolution in AML, we sequenced the genomes of AML samples with a known initiating event (PML-RARA) vs. normal karyotype AML samples, and the exomes of hematopoietic stem/progenitor cells (HSPCs) from healthy people. Collectively, the data suggest that most of the mutations found in AML genomes are actually random events that occurred in HSPCs before they acquired the initiating mutation; the mutational history of that cell is “captured” as the clone expands. In many cases, only one or two additional, cooperating mutations are needed to generate the malignant founding clone. Cells from the founding clone can acquire additional cooperating mutations, yielding subclones that can contribute to disease progression and/or relapse.
PMCID: PMC3407563  PMID: 22817890
11.  BreakDancer: An algorithm for high resolution mapping of genomic structural variation 
Nature methods  2009;6(9):677-681.
Detection and characterization of genomic structural variation are important for understanding the landscape of genetic variation in human populations and in complex diseases such as cancer. Recent studies demonstrate the feasibility of detecting structural variation using next-generation, short-insert, paired-end sequencing reads. However, the utility of these reads is not entirely clear, nor are the analysis methods under which accurate detection can be achieved. The algorithm BreakDancer predicts a wide variety of structural variants including indels, inversions, and translocations. We examined BreakDancer's performance in simulation, comparison with other methods, analysis of an acute myeloid leukemia sample, and the 1,000 Genomes trio individuals. We found that it substantially improved the detection of small and intermediate size indels from 10 bp to 1 Mbp that are difficult to detect via a single conventional approach.
PMCID: PMC3661775  PMID: 19668202
12.  Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content 
Nature  2010;463(7280):536-539.
The human Y chromosome began to evolve from an autosome hundreds of millions of years ago, acquiring a sex-determining function and undergoing a series of inversions that suppressed crossing over with the X chromosome1,2. Little is known about the Y chromosome’s recent evolution because only the human Y chromosome has been fully sequenced. Prevailing theories hold that Y chromosomes evolve by gene loss, the pace of which slows over time, eventually leading to a paucity of genes, and stasis3,4. These theories have been buttressed by partial sequence data from newly emergent plant and animal Y chromosomes5-8, but they have not been tested in older, highly evolved Y chromosomes like that of humans. We therefore finished sequencing the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY. We then compared the MSYs of the two species and found that they differ radically in sequence structure and gene content, implying rapid evolution during the past 6 million years. The chimpanzee MSY harbors twice as many massive palindromes as the human MSY, yet it has lost large fractions of the MSY protein-coding genes and gene families present in the last common ancestor. We suggest that the extraordinary divergence of the chimpanzee and human MSYs was driven by four synergistic factors: the MSY’s prominent role in sperm production, genetic hitchhiking effects in the absence of meiotic crossing over, frequent ectopic recombination within the MSY, and species differences in mating behavior. While genetic decay may be the principal dynamic in the evolution of newly emergent Y chromosomes, wholesale renovation is the paramount theme in the ongoing evolution of chimpanzee, human, and perhaps other older MSYs.
PMCID: PMC3653425  PMID: 20072128
13.  De Novo Gene Disruptions in Children on the Autistic Spectrum 
Neuron  2012;74(2):285-299.
Exome sequencing of 343 families, each with a single child on the autism spectrum and at least one unaffected sibling, reveal de novo small indels and point substitutions, which come mostly from the paternal line in an age-dependent manner. We do not see significantly greater numbers of de novo missense mutations in affected versus unaffected children, but gene-disrupting mutations (nonsense, splice site, and frame shifts) are twice as frequent, 59 to 28. Based on this differential and the number of recurrent and total targets of gene disruption found in our and similar studies, we estimate between 350 and 400 autism susceptibility genes. Many of the disrupted genes in these studies are associated with the fragile X protein, FMRP, reinforcing links between autism and synaptic plasticity. We find FMRP-associated genes are under greater purifying selection than the remainder of genes and suggest they are especially dosage-sensitive targets of cognitive disorders.
PMCID: PMC3619976  PMID: 22542183
14.  A Novel Anti-Inflammatory and Pro-Resolving Role for Resolvin D1 in Acute Cigarette Smoke-Induced Lung Inflammation 
PLoS ONE  2013;8(3):e58258.
Cigarette smoke is a profound pro-inflammatory stimulus that contributes to acute lung injuries and to chronic lung disease including COPD (emphysema and chronic bronchitis). Until recently, it was assumed that resolution of inflammation was a passive process that occurred once the inflammatory stimulus was removed. It is now recognized that resolution of inflammation is a bioactive process, mediated by specialized lipid mediators, and that normal homeostasis is maintained by a balance between pro-inflammatory and pro-resolving pathways. These novel small lipid mediators, including the resolvins, protectins and maresins, are bioactive products mainly derived from dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFA). We hypothesize that resolvin D1 (RvD1) has potent anti-inflammatory and pro-resolving effects in a model of cigarette smoke-induced lung inflammation.
Primary human lung fibroblasts, small airway epithelial cells and blood monocytes were treated with IL-1β or cigarette smoke extract in combination with RvD1 in vitro, production of pro-inflammatory mediators was measured. Mice were exposed to dilute mainstream cigarette smoke and treated with RvD1 either concurrently with smoke or after smoking cessation. The effects on lung inflammation and lung macrophage populations were assessed.
RvD1 suppressed production of pro-inflammatory mediators by primary human cells in a dose-dependent manner. Treatment of mice with RvD1 concurrently with cigarette smoke exposure significantly reduced neutrophilic lung inflammation and production of pro-inflammatory cytokines, while upregulating the anti-inflammatory cytokine IL-10. RvD1 promoted differentiation of alternatively activated (M2) macrophages and neutrophil efferocytosis. RvD1 also accelerated the resolution of lung inflammation when given after the final smoke exposure.
RvD1 has potent anti-inflammatory and pro-resolving effects in cells and mice exposed to cigarette smoke. Resolvins have strong potential as a novel therapeutic approach to resolve lung injury caused by smoke and pulmonary toxicants.
PMCID: PMC3590122  PMID: 23484005
15.  Novel mutations target distinct subgroups of medulloblastoma 
Nature  2012;488(7409):43-48.
Medulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development.
PMCID: PMC3412905  PMID: 22722829
16.  The Oxytricha trifallax Macronuclear Genome: A Complex Eukaryotic Genome with 16,000 Tiny Chromosomes 
PLoS Biology  2013;11(1):e1001473.
With more chromosomes than any other sequenced genome, the macronuclear genome of Oxytricha trifallax has a unique and complex architecture, including alternative fragmentation and predominantly single-gene chromosomes.
The macronuclear genome of the ciliate Oxytricha trifallax displays an extreme and unique eukaryotic genome architecture with extensive genomic variation. During sexual genome development, the expressed, somatic macronuclear genome is whittled down to the genic portion of a small fraction (∼5%) of its precursor “silent” germline micronuclear genome by a process of “unscrambling” and fragmentation. The tiny macronuclear “nanochromosomes” typically encode single, protein-coding genes (a small portion, 10%, encode 2–8 genes), have minimal noncoding regions, and are differentially amplified to an average of ∼2,000 copies. We report the high-quality genome assembly of ∼16,000 complete nanochromosomes (∼50 Mb haploid genome size) that vary from 469 bp to 66 kb long (mean ∼3.2 kb) and encode ∼18,500 genes. Alternative DNA fragmentation processes ∼10% of the nanochromosomes into multiple isoforms that usually encode complete genes. Nucleotide diversity in the macronucleus is very high (SNP heterozygosity is ∼4.0%), suggesting that Oxytricha trifallax may have one of the largest known effective population sizes of eukaryotes. Comparison to other ciliates with nonscrambled genomes and long macronuclear chromosomes (on the order of 100 kb) suggests several candidate proteins that could be involved in genome rearrangement, including domesticated MULE and IS1595-like DDE transposases. The assembly of the highly fragmented Oxytricha macronuclear genome is the first completed genome with such an unusual architecture. This genome sequence provides tantalizing glimpses into novel molecular biology and evolution. For example, Oxytricha maintains tens of millions of telomeres per cell and has also evolved an intriguing expansion of telomere end-binding proteins. In conjunction with the micronuclear genome in progress, the O. trifallax macronuclear genome will provide an invaluable resource for investigating programmed genome rearrangements, complementing studies of rearrangements arising during evolution and disease.
Author Summary
The macronuclear genome of the ciliate Oxytricha trifallax, contained in its somatic nucleus, has a unique genome architecture. Unlike its diploid germline genome, which is transcriptionally inactive during normal cellular growth, the macronuclear genome is fragmented into at least 16,000 tiny (∼3.2 kb mean length) chromosomes, most of which encode single actively transcribed genes and are differentially amplified to a few thousand copies each. The smallest chromosome is just 469 bp, while the largest is 66 kb and encodes a single enormous protein. We found considerable variation in the genome, including frequent alternative fragmentation patterns, generating chromosome isoforms with shared sequence. We also found limited variation in chromosome amplification levels, though insufficient to explain mRNA transcript level variation. Another remarkable feature of Oxytricha's macronuclear genome is its inordinate fondness for telomeres. In conjunction with its possession of tens of millions of chromosome-ending telomeres per macronucleus, we show that Oxytricha has evolved multiple putative telomere-binding proteins. In addition, we identified two new domesticated transposase-like protein classes that we propose may participate in the process of genome rearrangement. The macronuclear genome now provides a crucial resource for ongoing studies of genome rearrangement processes that use Oxytricha as an experimental or comparative model.
PMCID: PMC3558436  PMID: 23382650
17.  Laboratory test descriptions for bovine respiratory disease diagnosis and their strengths and weaknesses: Gold standards for diagnosis, do they exist? 
The Canadian Veterinary Journal  2012;53(7):754-761.
The diagnosis of bovine respiratory diseases (BRD) poses significant challenges to the clinician as there are numerous infectious etiologies, operating singly or most often in combination. Clinical signs alone may not be diagnostic and the diagnostic laboratory is often used to assist the clinician. Recently many molecular-based tests have been taken from the research laboratory to the veterinary diagnostic laboratory. This review describes the “traditional tests” and several “molecular tests” and discusses the benefits and limitations of the tests and their interpretation. Clinicians should consult with their diagnostic laboratory regarding the interpretation of the test results. The rate of development and use of molecular diagnostic tests have outpaced validation, standardization, and standards for interpretation relative to their use in BRD diagnostics.
PMCID: PMC3377458  PMID: 23277642
18.  Whole Genome Analysis Informs Breast Cancer Response to Aromatase Inhibition 
Nature  2012;486(7403):353-360.
To correlate the variable clinical features of estrogen receptor positive (ER+) breast cancer with somatic alterations, we studied pre-treatment tumour biopsies accrued from patients in a study of neoadjuvant aromatase inhibitor (AI) therapy by massively parallel sequencing and analysis. Eighteen significantly mutated genes were identified, including five genes (RUNX1, CBFB, MYH9, MLL3 and SF3B1) previously linked to hematopoietic disorders. Mutant MAP3K1 was associated with Luminal A status, low grade histology and low proliferation rates whereas mutant TP53 associated with the opposite pattern. Moreover, mutant GATA3 correlated with suppression of proliferation upon AI treatment. Pathway analysis demonstrated mutations in MAP2K4, a MAP3K1 substrate, produced similar perturbations as MAP3K1 loss. Distinct phenotypes in ER+ breast cancer are associated with specific patterns of somatic mutations that map into cellular pathways linked to tumor biology but most recurrent mutations are relatively infrequent. Prospective clinical trials based on these findings will require comprehensive genome sequencing.
PMCID: PMC3383766  PMID: 22722193
19.  A framework for human microbiome research 
Methé, Barbara A. | Nelson, Karen E. | Pop, Mihai | Creasy, Heather H. | Giglio, Michelle G. | Huttenhower, Curtis | Gevers, Dirk | Petrosino, Joseph F. | Abubucker, Sahar | Badger, Jonathan H. | Chinwalla, Asif T. | Earl, Ashlee M. | FitzGerald, Michael G. | Fulton, Robert S. | Hallsworth-Pepin, Kymberlie | Lobos, Elizabeth A. | Madupu, Ramana | Magrini, Vincent | Martin, John C. | Mitreva, Makedonka | Muzny, Donna M. | Sodergren, Erica J. | Versalovic, James | Wollam, Aye M. | Worley, Kim C. | Wortman, Jennifer R. | Young, Sarah K. | Zeng, Qiandong | Aagaard, Kjersti M. | Abolude, Olukemi O. | Allen-Vercoe, Emma | Alm, Eric J. | Alvarado, Lucia | Andersen, Gary L. | Anderson, Scott | Appelbaum, Elizabeth | Arachchi, Harindra M. | Armitage, Gary | Arze, Cesar A. | Ayvaz, Tulin | Baker, Carl C. | Begg, Lisa | Belachew, Tsegahiwot | Bhonagiri, Veena | Bihan, Monika | Blaser, Martin J. | Bloom, Toby | Vivien Bonazzi, J. | Brooks, Paul | Buck, Gregory A. | Buhay, Christian J. | Busam, Dana A. | Campbell, Joseph L. | Canon, Shane R. | Cantarel, Brandi L. | Chain, Patrick S. | Chen, I-Min A. | Chen, Lei | Chhibba, Shaila | Chu, Ken | Ciulla, Dawn M. | Clemente, Jose C. | Clifton, Sandra W. | Conlan, Sean | Crabtree, Jonathan | Cutting, Mary A. | Davidovics, Noam J. | Davis, Catherine C. | DeSantis, Todd Z. | Deal, Carolyn | Delehaunty, Kimberley D. | Dewhirst, Floyd E. | Deych, Elena | Ding, Yan | Dooling, David J. | Dugan, Shannon P. | Dunne, Wm. Michael | Durkin, A. Scott | Edgar, Robert C. | Erlich, Rachel L. | Farmer, Candace N. | Farrell, Ruth M. | Faust, Karoline | Feldgarden, Michael | Felix, Victor M. | Fisher, Sheila | Fodor, Anthony A. | Forney, Larry | Foster, Leslie | Di Francesco, Valentina | Friedman, Jonathan | Friedrich, Dennis C. | Fronick, Catrina C. | Fulton, Lucinda L. | Gao, Hongyu | Garcia, Nathalia | Giannoukos, Georgia | Giblin, Christina | Giovanni, Maria Y. | Goldberg, Jonathan M. | Goll, Johannes | Gonzalez, Antonio | Griggs, Allison | Gujja, Sharvari | Haas, Brian J. | Hamilton, Holli A. | Harris, Emily L. | Hepburn, Theresa A. | Herter, Brandi | Hoffmann, Diane E. | Holder, Michael E. | Howarth, Clinton | Huang, Katherine H. | Huse, Susan M. | Izard, Jacques | Jansson, Janet K. | Jiang, Huaiyang | Jordan, Catherine | Joshi, Vandita | Katancik, James A. | Keitel, Wendy A. | Kelley, Scott T. | Kells, Cristyn | Kinder-Haake, Susan | King, Nicholas B. | Knight, Rob | Knights, Dan | Kong, Heidi H. | Koren, Omry | Koren, Sergey | Kota, Karthik C. | Kovar, Christie L. | Kyrpides, Nikos C. | La Rosa, Patricio S. | Lee, Sandra L. | Lemon, Katherine P. | Lennon, Niall | Lewis, Cecil M. | Lewis, Lora | Ley, Ruth E. | Li, Kelvin | Liolios, Konstantinos | Liu, Bo | Liu, Yue | Lo, Chien-Chi | Lozupone, Catherine A. | Lunsford, R. Dwayne | Madden, Tessa | Mahurkar, Anup A. | Mannon, Peter J. | Mardis, Elaine R. | Markowitz, Victor M. | Mavrommatis, Konstantinos | McCorrison, Jamison M. | McDonald, Daniel | McEwen, Jean | McGuire, Amy L. | McInnes, Pamela | Mehta, Teena | Mihindukulasuriya, Kathie A. | Miller, Jason R. | Minx, Patrick J. | Newsham, Irene | Nusbaum, Chad | O’Laughlin, Michelle | Orvis, Joshua | Pagani, Ioanna | Palaniappan, Krishna | Patel, Shital M. | Pearson, Matthew | Peterson, Jane | Podar, Mircea | Pohl, Craig | Pollard, Katherine S. | Priest, Margaret E. | Proctor, Lita M. | Qin, Xiang | Raes, Jeroen | Ravel, Jacques | Reid, Jeffrey G. | Rho, Mina | Rhodes, Rosamond | Riehle, Kevin P. | Rivera, Maria C. | Rodriguez-Mueller, Beltran | Rogers, Yu-Hui | Ross, Matthew C. | Russ, Carsten | Sanka, Ravi K. | Pamela Sankar, J. | Sathirapongsasuti, Fah | Schloss, Jeffery A. | Schloss, Patrick D. | Schmidt, Thomas M. | Scholz, Matthew | Schriml, Lynn | Schubert, Alyxandria M. | Segata, Nicola | Segre, Julia A. | Shannon, William D. | Sharp, Richard R. | Sharpton, Thomas J. | Shenoy, Narmada | Sheth, Nihar U. | Simone, Gina A. | Singh, Indresh | Smillie, Chris S. | Sobel, Jack D. | Sommer, Daniel D. | Spicer, Paul | Sutton, Granger G. | Sykes, Sean M. | Tabbaa, Diana G. | Thiagarajan, Mathangi | Tomlinson, Chad M. | Torralba, Manolito | Treangen, Todd J. | Truty, Rebecca M. | Vishnivetskaya, Tatiana A. | Walker, Jason | Wang, Lu | Wang, Zhengyuan | Ward, Doyle V. | Warren, Wesley | Watson, Mark A. | Wellington, Christopher | Wetterstrand, Kris A. | White, James R. | Wilczek-Boney, Katarzyna | Wu, Yuan Qing | Wylie, Kristine M. | Wylie, Todd | Yandava, Chandri | Ye, Liang | Ye, Yuzhen | Yooseph, Shibu | Youmans, Bonnie P. | Zhang, Lan | Zhou, Yanjiao | Zhu, Yiming | Zoloth, Laurie | Zucker, Jeremy D. | Birren, Bruce W. | Gibbs, Richard A. | Highlander, Sarah K. | Weinstock, George M. | Wilson, Richard K. | White, Owen
Nature  2012;486(7402):215-221.
A variety of microbial communities and their genes (microbiome) exist throughout the human body, playing fundamental roles in human health and disease. The NIH funded Human Microbiome Project (HMP) Consortium has established a population-scale framework which catalyzed significant development of metagenomic protocols resulting in a broad range of quality-controlled resources and data including standardized methods for creating, processing and interpreting distinct types of high-throughput metagenomic data available to the scientific community. Here we present resources from a population of 242 healthy adults sampled at 15 to 18 body sites up to three times, which to date, have generated 5,177 microbial taxonomic profiles from 16S rRNA genes and over 3.5 Tb of metagenomic sequence. In parallel, approximately 800 human-associated reference genomes have been sequenced. Collectively, these data represent the largest resource to date describing the abundance and variety of the human microbiome, while providing a platform for current and future studies.
PMCID: PMC3377744  PMID: 22699610
21.  A dominant mutation in RPE65 identified by whole-exome sequencing causes retinitis pigmentosa with choroidal involvement 
European Journal of Human Genetics  2011;19(10):1074-1081.
Linkage testing using Affymetrix 6.0 SNP Arrays mapped the disease locus in TCD-G, an Irish family with autosomal dominant retinitis pigmentosa (adRP), to an 8.8 Mb region on 1p31. Of 50 known genes in the region, 11 candidates, including RPE65 and PDE4B, were sequenced using di-deoxy capillary electrophoresis. Simultaneously, a subset of family members was analyzed using Agilent SureSelect All Exome capture, followed by sequencing on an Illumina GAIIx platform. Candidate gene and exome sequencing resulted in the identification of an Asp477Gly mutation in exon 13 of the RPE65 gene tracking with the disease in TCD-G. All coding exons of genes not sequenced to sufficient depth by next generation sequencing were sequenced by di-deoxy sequencing. No other potential disease-causing variants were found to segregate with disease in TCD-G. The Asp477Gly mutation was not present in Irish controls, but was found in a second Irish family provisionally diagnosed with choroideremia, bringing the combined maximum two-point LOD score to 5.3. Mutations in RPE65 are a known cause of recessive Leber congenital amaurosis (LCA) and recessive RP, but no dominant mutations have been reported. Protein modeling suggests that the Asp477Gly mutation may destabilize protein folding, and mutant RPE65 protein migrates marginally faster on SDS-PAGE, compared with wild type. Gene therapy for LCA patients with RPE65 mutations has shown great promise, raising the possibility of related therapies for dominant-acting mutations in this gene.
PMCID: PMC3190249  PMID: 21654732
retinitis pigmentosa; choroideremia; RPE65; exome capture; next-generation sequencing
22.  Clonal Architecture of Secondary Acute Myeloid Leukemia 
The New England Journal of Medicine  2012;366(12):1090-1098.
The myelodysplastic syndromes are a group of hematologic disorders that often evolve into secondary acute myeloid leukemia (AML). The genetic changes that underlie progression from the myelodysplastic syndromes to secondary AML are not well understood.
We performed whole-genome sequencing of seven paired samples of skin and bone marrow in seven subjects with secondary AML to identify somatic mutations specific to secondary AML. We then genotyped a bone marrow sample obtained during the antecedent myelodysplastic-syndrome stage from each subject to determine the presence or absence of the specific somatic mutations. We identified recurrent mutations in coding genes and defined the clonal architecture of each pair of samples from the myelodysplastic-syndrome stage and the secondary-AML stage, using the allele burden of hundreds of mutations.
Approximately 85% of bone marrow cells were clonal in the myelodysplastic-syndrome and secondary-AML samples, regardless of the myeloblast count. The secondary-AML samples contained mutations in 11 recurrently mutated genes, including 4 genes that have not been previously implicated in the myelodysplastic syndromes or AML. In every case, progression to acute leukemia was defined by the persistence of an antecedent founding clone containing 182 to 660 somatic mutations and the outgrowth or emergence of at least one subclone, harboring dozens to hundreds of new mutations. All founding clones and subclones contained at least one mutation in a coding gene.
Nearly all the bone marrow cells in patients with myelodysplastic syndromes and secondary AML are clonally derived. Genetic evolution of secondary AML is a dynamic process shaped by multiple cycles of mutation acquisition and clonal selection. Recurrent gene mutations are found in both founding clones and daughter subclones. (Funded by the National Institutes of Health and others.)
PMCID: PMC3320218  PMID: 22417201
23.  Strict evolutionary conservation followed rapid gene loss on human and rhesus Y chromosomes 
Nature  2012;483(7387):82-86.
The human X and Y chromosomes evolved from an ordinary pair of autosomes during the past 200–300 million years1–3. Due to genetic decay, the human MSY (male-specific region of Y chromosome) retains only three percent of the ancestral autosomes’ genes4,5. This evolutionary decay was driven by a series of five “stratification” events. Each event suppressed X-Y crossing over within a chromosome segment or “stratum”, incorporated that segment into the MSY, and subjected its genes to the erosive forces that attend the absence of crossing over2,6. The last of these events occurred 30 million years ago (mya), or 5 million years before the human and Old World monkey (OWM) lineages diverged. Although speculation abounds regarding ongoing decay and looming extinction of the human Y chromosome7–10, remarkably little is known about how many MSY genes were lost in the human lineage in the 25 million years that have followed its separation from the OWM lineage. To explore this question, we sequenced the MSY of the rhesus macaque, an OWM, and compared it to the human MSY. We discovered that, during the last 25 million years, MSY gene loss in the human lineage was limited to the youngest stratum (stratum 5), which comprises three percent of the human MSY. Within the older strata, which collectively comprise the bulk of the human MSY, gene loss evidently ceased more than 25 mya. Likewise, the rhesus MSY has not lost any older genes (from strata 1–4) during the past 25 million years, despite major structural differences from the human MSY. The rhesus MSY is simpler, with few amplified gene families or palindromes that might enable intrachromosomal recombination and repair. We present an empirical reconstruction of human MSY evolution in which each stratum transitioned from rapid, exponential loss of ancestral genes to strict conservation through purifying selection.
PMCID: PMC3292678  PMID: 22367542
24.  Clonal evolution in relapsed acute myeloid leukemia revealed by whole genome sequencing 
Nature  2012;481(7382):506-510.
Most patients with acute myeloid leukemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level1,2. To determine the mutational spectrum associated with relapse, we sequenced the primary tumor and relapse genomes from 8 AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to precisely define clonality and clonal evolution patterns at relapse. Besides discovering novel, recurrently mutated genes (e.g. WAC, SMC3, DIS3, DDX41, and DAXX) in AML, we found two major clonal evolution patterns during AML relapse: 1) the founding clone in the primary tumor gained mutations and evolved into the relapse clone, or 2) a subclone of the founding clone survived initial therapy, gained additional mutations, and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific vs. primary tumor mutations in all 8 cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped in part by the chemotherapy that the patients receive to establish and maintain remissions.
PMCID: PMC3267864  PMID: 22237025
25.  A Novel Retinoblastoma Therapy from Genomic and Epigenetic Analyses 
Nature  2012;481(7381):329-334.
Retinoblastoma is an aggressive childhood cancer of the developing retina that is initiated by the biallelic loss of the RB1 gene. To identify the mutations that cooperate with RB1 loss, we performed whole-genome sequencing of retinoblastomas. The overall mutational rate was very low; RB1 was the only known cancer gene mutated. We then evaluated RB1’s role in genome stability and considered nongenetic mechanisms of cancer pathway deregulation. Here we show that the retinoblastoma genome is stable, but multiple cancer pathways can be epigenetically deregulated. For example, the proto-oncogene SYK is upregulated in retinoblastoma and is required for tumor cell survival. Targeting SYK with a small-molecule inhibitor induced retinoblastoma tumor cell death in vitro and in vivo. Thus, RB1 inactivation may allow preneoplastic cells to acquire multiple hallmarks of cancer through epigenetic mechanisms, resulting directly or indirectly from RB1 loss. These data provide novel targets for chemotherapeutic interventions of retinoblastoma.
PMCID: PMC3289956  PMID: 22237022

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