Quantitative Analysis of Chiari-Like Malformation and Syringomyelia in the Griffon Bruxellois Dog

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

This study aimed to develop a system of quantitative analysis of canine Chiari-like malformation and syringomyelia on variable quality MRI. We made a series of measurements from magnetic resonance DICOM images from Griffon Bruxellois dogs with and without Chiari-like malformation and syringomyelia and identified several significant variables. We found that in the Griffon Bruxellois dog, Chiari-like malformation is characterized by an apparent shortening of the entire cranial base and possibly by increased proximity of the atlas to the occiput. As a compensatory change, there appears to be an increased height of the rostral cranial cavity with lengthening of the dorsal cranial vault and considerable reorganization of the brain parenchyma including ventral deviation of the olfactory bulbs and rostral invagination of the cerebellum under the occipital lobes.

Related collections

Most cited references 31

Record: found
Abstract: found
Article: found

Is Open Access

Variation of BMP3 Contributes to Dog Breed Skull Diversity

Jeffrey J. Schoenebeck, Sarah A Hutchinson, Alexandra M Byers … (2012)

Introduction Canine skull shape variation among dog breeds is in large part a human-created phenomenon, occurring through artificial selection and consolidation of desired traits. Morphological distinction between wolves and dogs dates as far back as 31,000 years ago [1], [2]. Changes in skull shape are a key feature of dog domestication, foreshadowing the wide variety of shapes displayed by modern dog breeds. Skull shapes differ tremendously from one another, so much so that such differences are breed-defining. Two such skull shapes are brachycephaly (“shortened head”, e.g. Bulldog, Pug, Boxer) and dolichocephaly (“elongated head”, e.g. Greyhound, Saluki, Collie), which are named after their resemblance to human cephalic disorders. Although canine cranial shape is subject to multigenic control [3]–[5], the molecular underpinnings of this variation remain poorly defined. Candidate gene studies failed to uncover compelling causal variants of canine brachycephaly [6]–[8]. Airorhynchy (dorsal bending of the snout; a feature common to brachycephalic breeds) and midface length was previously correlated with polyglutamine and polyalanine repeat length of the transcription factor RUNX2 [4]. More recently, genome wide association scans (GWAS) and homozygosity mapping have converged on chromosome 1 (CFA1) as a locus that is highly associated with brachycephaly, implicating a 296 kb haplotype that spans THSB2 and intergenic sequence proximal to SMOC2 [3], [9], [10]. Here we present data indicating that at least five genetic loci are responsible for the cranioskeletal differences that differentiate dolichocephalic and brachycephalic dog breeds. Our conclusions are based on a GWAS that coupled craniometric breed-sex averages collected from 533 modern specimens from museum and private collections with the genetic profiles of 576 purebred dogs (62 breeds) assayed via single nucleotide polymorphism (SNP) chips. To identify candidates of phenotype causality, we filtered genetic variants derived from whole genome sequencing of eleven different breeds. This led to discovery of a compelling candidate for causality at the CFA32 QTL: a derived missense mutation in BMP3 that is nearly fixed among small, brachycephalic dog breeds. To evaluate the functional potential of this variant in vivo, we turned to zebrafish. We show that Bmp3 is indispensable for normal craniofacial development in zebrafish, and comparison of missexpression assays using BMP3 and its canine variant suggests enhanced activity in the latter. Together, our data reveal for the first time the molecular underpinnings of a quantitative trait, selected by dog fanciers to modulate a prominent morphological trait in domestic dogs. Results To capture the three-dimensional morphological complexities present among modern dogs, we digitized 51 stereotyped landmarks from 533 skulls representing 120 breeds and four gray wolf subspecies (Figure 1A–1D, Figure S1A–S1E, Tables S1 and S2). As most skulls used in our study originated from museums, we selected only those specimens with unambiguous breed designations, sex status, and recent time of death (within the past 40 years) for use in this study. Using MorphoJ software [11], we identified four principal components that accounted for nearly 75.5% of shape variance, with the majority of variance explained by the first component (PC1 = 59.4%, PC2 = 8.2%, PC3 = 4.2%, PC4 = 3.8%). PC1 describes profound changes in rostrum length and angle, palate and zygomatic arch width, and depth of the neurocranium: essentially the continuum of cranioskeletal features that extend between dolichocephalic and brachycephalic breeds (Figure 1E, 1F). 10.1371/journal.pgen.1002849.g001 Figure 1 Quantitative and qualitative assessments of PC1 on canine cranioskeletal shape. (A) Gray wolf (mesocephalic, ancestor to dogs) (B) Afghan hound (dolichocephalic), (C) Leonberger (mesocephalic), (D) Pug (brachycephalic). (E) Boxplots of PC1 (corresponding breed names are listed in Table S2). (F) Surface scans of a gray wolf skull illustrate morphological changes associated with PC1. Columns (left to right) are dorsal, lateral, and rostral views. Top row: a gray wolf skull morphed by positive PC1. Middle row: a gray wolf skull (no morphing). Bottom row: a gray wolf skull morphed by negative PC1. Pseudocoloring of the gray wolf skull indicates rostrum (ros) and neurocranium (nc). Line indicates width of the zygomatic arches (za). Since purebred dogs must conform to specific morphological standards [12], morphological traits like skull shape became highly uniform by breed, permitting association studies using one set of samples for genotyping and others for phenotyping. This strategy of using breed stereotypes has proven successful in mapping a number of canine morphologic traits by independent groups [3], [13], [14]. Using breed allele frequencies collected by the CanMap project [3], we conducted genome-wide scans of QTLs associated with breed-sex averages for PC1 (1–10 specimen(s)/breed/sex, mean n = 3, Table S3). Initially, we scanned for PC1 associations using an additive linear regression model (Figure S2A, Table S4) [15]. Size correction in the regression suggested potential confounders (compare Figure S2A and S2B) on CFA10 and 15, which were previously associated with body size [3], [13], [14], [16]. As expected, addition of log(neurocranium centroid) breed-sex values as a covariate removed those associations (Figure S2B, see Materials and Methods for more details). False associations derived from breed relatedness were excluded using GEMMA [17]. Discounting associations on CFA10 and 15, we identified six PC1-associated regions of interest indicated by SNPs at CFA1.59832965, CFA5.32359028, CFA24.26359293, CFA30.35656568, CFA32.8384767, and CFAX.44401786 (−log10(P) = 6.13–17.9, Figure 2A, Table S4). Of note, a suggestive association on CFAX was also observed, marked by SNP CFAX.104724717. Including a neurocranium centroid size covariate in the mixed-model removed associations at CFA10 and 15, as well as those on CFA30, 32, and X.44401786 and enhanced the association on CFAX.104724717 to significance (Figure 2B, Table S4). Since nearly all extreme brachycephalic breeds used in our study are also small breeds, and therefore substantially related to small, non-brachycephalic breeds, we reasoned that use of a size covariate in the mixed-model was overcorrecting associations that could be driven by diminutive breeds [3], [18], [19]. To reduce the contrast in relatedness among our study population, we reran the mixed-model using only breeds with a log(neurocranium centroid) below the 50th percentile. This resulted in recovery of the CFA32 QTL, as well as new associations marked by SNPs at CFA9.50988217 and CFA13.26492600. Although the association on CFA30 remained below threshold for statistical significance, its association markedly improved (Figure 2C). When brachycephalic breeds were removed from the mixed-model, all aforementioned markers dropped below significance except for CFA5.36476657 (Figure 2D). Summarizing these findings, QTLs on CFA1, 5, 24, 32, and X (X:104724717) account for skull shape changes that occur along the continuum of canine brachycephaly-dolichocephaly. Additional associations reside on CFA9, CFA13, CFA30, and CFAX (X: 44401786), though their instability across mixed-model scans suggest they are either allometric in nature, driven by variation that is marginally represented by the breed composition present in our GWAS, or possibly false positives (Figure 2A–2D, Table S4). 10.1371/journal.pgen.1002849.g002 Figure 2 PC1 GWAS and fine mapping at CFA32. All GWAS used the mixed-model GEMMA. Chromosomes listed on the x-axis, −log10(P) on the y-axis. SNPs remaining significant following Bonferroni correction are colored blue. Q-Q plots of observed versus expected −log10(P) are depicted on right, with full SNP dataset (black circles), pruned dataset (grey circles), expected values (red lines), and 95% confidence intervals (black lines). Scan results using breed-sex averages of PC1 without (A) and with a breed-sex average size covariate (B). Including a size covariate in the mixed-model overcorrects, leading to loss of associations on CFA 30 and 32.(C) Scan results using PC1 breed-sex averages and breed-sex size covariates. In this scan, only breeds whose neurocranium size ranked within the smallest 50% of our dataset where analyzed. By reducing relatedness disparity in our study population, the association on CFA32 remains significant despite size correction. (D) Scan results using all breed-sex averages of PC1, but excluding extreme brachycephalic breeds (Pug, Pekingese, Boston Terrier, Shih Tzu, Brussels Griffon, French Bulldog, Bulldog, Boxer, Cavalier King Charles Spaniel, Chihuahua). (E) Average log(HO ratios) or FST from ten-SNP sliding windows. (F) Regional HO or FST values, and their respective Lowess best fit curves. Because shape variation is the result of artificial selection, we expected critical loci to be marked by reduction of observed heterozygosity (Ho) and elevated genetic differentiation (FST), hallmarks of selective sweeps [20], [21]. Among autosomes, QTLs on CFA1, 5, 30, and 32 displayed particularly strong reductions in HO among brachycephalic breeds, relative to dolichocephalic breeds (HR, see Materials and Methods). Sliding HR windows corresponding to these QTLs placed with the smallest 0.01. In the full dataset (all breeds with breed-sex PC1 averages), 61,270 SNPs were analyzed by PLINK from 576 dogs representing 62 American Kennel Club-recognized breeds. In the mixed-model, ∼36,685 SNPs were analyzed. Breeds used in size-stratified analyses are listed in Table S2. Significantly associated SNPs surpassed Bonferroni correction at the 0.05 level (−log10(P)> = 5.86). HO was calculated by treating CanMap breeds at the polar extremes of PC1 as two comparisons populations (Pug, Pekingese, Boston Terrier, Shih Tzu, Brussels Griffon, French Bulldog, Bulldog, Boxer, Cavalier King Charles Spaniel, Chihuahua versus Collie, Borzoi, Saluki, Scottish Deerhound, Bloodhound, Greyhound, Scottish Terrier, Doberman Pinscher, and Irish Wolfhound). FST was calculated treating brachycephalic breeds (listed above) as a single subpopulation. HO, HR (the ratio of dolicho- and brachycephalic HO), and FST values were calculated using custom R scripts. fastPHASE was used to generate haplotype frequencies by breed, using CanMap genotypes using the clustering parameter k = 15 [35]. “Extreme brachycephalic breeds” were designated as such if both PC1 breed-sex averages exceeded 0.15. This cutoff was chosen based on the obvious jump in magnitude of PC1 values (see Figure 1E, Figure S6). Breeds that meet this classification include the Pug, Pekingese, Boston Terrier, French Bulldog, Bulldog, Brussels Griffon, and Shih Tzu. Sample collection, Sanger sequencing, and genotyping DNA used in our study was extracted from blood samples as previously described [16]. In addition to whole-genome sequencing (see below), BMP3 and PRKG2 were Sanger sequenced using six brachycephalic and six dolichocephalic breeds (data not shown). The BMP3 8,196,098 C/A transversion was sequenced in an expanded panel composed of 847 dogs from 113 breeds. Primers were designed with a melting temperature (Tm) ranging between 68–72°C, GC content ranging between 20–80%, length ranging between 18–32 nucleotides, and included 5′ M13 tags (Table S10). PCR products for sequencing were generated with a 2-step thermocycler program: Initial Denaturation: 1×—95°C, 5 minutes Two-step Cycles: 35×—95°C, 30 seconds; 68°C, 2 minutes Extension: 1×—72°C, 10 minutes PCR products were sequenced using a standard protocol [16]. During the course of SNP discovery, we discovered errors in the reference genome sequence for canine BMP3, producing two early stop codons in the first exon. Sequencing of 13 dogs, including the individual from which the reference genome sequence was derived, indicates these stop codons are the results of errors in the reference sequence. Whole-genome sequencing and variant filtering Paired-end libraries were prepared from DNA from eleven dogs of breeds with widely varying skull shapes. Sequencing was conducted on an Illumina HiSeq 2000 sequencer to a depth of 5.6–8.5× per dog using manufacturer protocols. The resulting 101-base paired-end sequences were mapped to the genome (CanFam2 release May 2005) with bwa version 0.5.9-r16 with read trimming set to 15. SNPs were called with samtools mpileup version 0.1.18 and custom R scripts [36]–[39]. Thirteen SNPs in the PC1-associated region overlap with the CanineHD Genotyping BeadChip (Illumina cat. no. WG-440). DNA from four dogs was assayed with the chip; all resulting genotypes were identical in the deep sequencing and chip results. Four hundred and fifty-two SNPs were identified in the critical interval (85.7 kb between 8,152,258 and 8,237,937), and subjected to further filters. Genotypes with a genotype quality score below 8 were reset to “unknown.” We performed association analysis using PLINK with options specifying an additive model omitting the Scottish Terrier, a dolichocephalic breed that appears to be an outlier [15]. After correcting for multiple testing, no SNPs were significantly associated due to limited statistical strength of the test. SNPs in the 5th percentile for association scores were retained. Cross-species conservation was assessed by the UCSC phastCons4way calculations [40] downloaded November 30, 2011, which is generated by using the phastCons program to score the extent of conservation between dog, human, mouse and rat. SNPs with a phastCons4way score above 0.7 were retained. SNPs in an exon or within 20 bases of a splice junction were retained. Morpholino injections Morpholino knockdown experiments of bmp3 used two translation blockers (MO1: 5′-TGACAGCGATCCATGCTGGAGGTGC-3′, MO2 5′-CGGGACTATGGAAGCTGATCTA-3′), which overlapped by one nucleotide. Morpholino injections used 5.1 ng (MO1) or 7.5 ng (MO2), as determined by titrations. RNA synthesis and injections Zebrafish bmp3 (IMAGE Id 7052011) and human BMP3 (Origene clone SC302990) cDNAs were sequenced and determined to be full length. Missense F→L mutations for mouse GDF1 [41], human Bmp3, and zebrafish bmp2b [42] were introduced using site-directed mutagenesis and confirmed by sequencing. Zebrafish bmp3 wt and F→L cDNAs were PCR-amplified using gene-specific primers with attB sites. PCR products were subcloned into entry and destination vectors (pCSDest) using Gateway recombination, as previously described [43], [44]. To construct the human BMP3 expression vector, we PCR-amplified the TGF-β signaling domain using primers with XbaI and XhoI restriction sites. PCR products were ligated into an expression vector bearing the Xenopus BMP2 prodomain, as such heterologous fusion constructs were previously shown to enhance propeptide cleavage and biological activity [41]. mRNA was synthesized using Ambion's SP6 mMessage kit from plasmid that was linearized with Not I. Embryo analyses of RNA injections were done based on injections of the following amounts: 25–300 pg human BMP3 mRNA, 25–300 pg mouse Gdf1 mRNA, 1–100 pg zebrafish bmp2b. mRNA overexpression assays were repeated three or more times at each stated concentration, unless stated otherwise. In Situ and Alcian blue stains In situ hybridization was completed as described in Thisse and Thisse 2008 [45], except probes were hydrolyzed for 2 minutes at 65°C, the hybridization solution contained 5% dextran sulfate, and the anti-DIG-AP incubation and subsequent washes were performed in Malic Acid Buffer rather than PBST. Alcian blue stains were done as previously described by Schilling et al. [46], except that staining solution was composed of 0.15% Alcian blue, 50% EtOH, and 0.1 M HCl (pH = ∼1). Plots and images Embryos were imaged using Zeiss Axio Imager.M1, Zeiss SteREO Lumar v12, or Leica M216F compound microscope. Zeiss Axiovision v4.8.1 software was used for image capture. Nonspecific background and dissection debris were removed from images of Alcian blue cartilage dissections using Adobe Photoshop CS3. All plots were generated using custom scripts, in conjunction with R Cran packages ggplot2 [38], reshape2 [39], and RColorbrewer [47]. Manhattan plot and Q-Q plot scripts were adapted from examples posted on the blog “Getting Genetics Done” [48]. Post-processing of plots was done using Adobe CS4 Creative Suite softwares Photoshop, InDesign, and Illustrator. Ethics statement Informed consent was obtained for all collected dog samples. All animal protocols (dog and zebrafish) were approved by the Animal Care and Use Committees of the Intramural Program of the National Human Genome Research Institute at the National Institutes of Health or by Animal Care Committee of the Hospital for Sick Children Research Institute. Wild canids samples were graciously provided by Dr. Robert Wayne, in accordance with UCLA Approved Animal Care and Use Committee Policies. Supporting Information Figure S1 Diagrams of 51 cranioskeletal landmarks captured with a microscribe digitizer. See Table S1 for anatomical descriptions corresponding to numbering. (a–e) Anterior facing left. (A) Dorsal and (B) Ventral views. (C) Lateral view (left side). (D) Oblique lateral, intraorbital view (left). (E) Caudal view. Indications include the rostrum (white brackets), palate and zygomatic arch (white lines), and neurocranium (dashed ovoid). Color indicates landmarks used for calculating the neurocranium centroid (blue). (TIF) Click here for additional data file. Figure S2 PC1 GWAS results from PLINK linear regressions with and without a size covariate. (A and B) x-axis indicates chromosome, y-axis indicates −log10(P-value). (A) Univariate analysis suggests multiple, highly significant loci are associated with PC1 skull shape. (B) Correction for size using breed averages of the log(neurocranium centroid) indicates that associations on CFA10 (HMGA2 locus) and CFA15 (IGF1 locus) are lost upon correction (compare green arrows). (TIF) Click here for additional data file. Figure S3 Selective sweeps detected at QTLs on CFA1, 5, and 30. CFA1 (A–C), CFA5 (D–F), CFA30 (G–I). Line graphs plot 10-SNP sliding window averages for log(HO ratios) (A,D,G) or FST (B,E,H) for each chromosome. Scatterplots depict regional views of SNP values for HO or FST and include Lowess best fit curves (C,F,I). Color coding corresponds to dolichocephalic breeds (blue), brachycephalic breeds (purple), and FST treating brachycephalic breeds as a subpopulation (green). (TIF) Click here for additional data file. Figure S4 Overexpression activity differs between BMP3 variants. Overexpression utilized human BMP3 constructs, since the mature peptides of human and dog/wolf BMP3 are identical. (A–C) Whole mount embryos at embryonic stage 24 hpf, anterior to the left. Phenotypes are representative of (A) normal, (B) dorsalized, (C) mildly dorsalized classes following injection of human BMP3 mRNA into one-cell staged zebrafish embryos. (D) Stacked bar graph summarizing phenotypes observed following wt BMP3 or BMP3F452L mRNA injection. The dysmorphic phenotypes classified as “other” included combinations of mild dorsalization, tail curving, occlusion of the yolk extension, and invariably, hypoplasia or necrosis of head structures. Doses listed are in picograms (pg) of mRNA (x-axis). The frequencies of phenotypes are indicated by the y-axis. Each dose was repeated five or more times. The number of embryos injected is listed above each dose. Injection of BMP3F452L more potently dorsalizes embryos compared to wt BMP3 (student's t-test P<0.05 for 25–75 pg doses, <0.01 for 100 pg dose). (TIF) Click here for additional data file. Figure S5 Y/F→L substitutions differentially affect Tgfßs. (A–C,E–G) Whole mount embryos at embryonic stage 24 hpf (A–C) or 28 hpf (E–G), anterior to the left. Phenotypes are representative of (A,E) normal, (B) dorsalized, (C) mildly dorsalized, (F) ventralized, (G) mildly ventralized classes following injections. (A–D) Embryos injected with mouse Gdf1or Gdf1F→L mRNA. (E–H) Embryos injected with either zebrafish bmp2b or bmp2bY→L mRNA. (D,H) Stacked bar graphs depicting frequency of observed phenotypes. Number of embryos injected per mRNA concentration appears above columns. While a missense mutation strongly reduces GDF1 dorsalizing activity, a comparable mutation in Bmp2b has little affect on this molecule's ventralizing activity. (TIF) Click here for additional data file. Figure S6 Histogram of PC1 breed-sex values. Extreme brachycephalic breeds were defined by their isolation from the main distribution of PC1. (TIF) Click here for additional data file. Table S1 Fifty-one landmarks measured by microscribe digitizer. Location of each landmark is described by the right column (compare with Figure S1). (XLS) Click here for additional data file. Table S2 Canid skull sources used in morphometric analyses. ID (first column) refers to each collection's numerical identifiers, when assigned. Collection abbreviations correspond to the following: Skulls Unlimited Museum of Osteology (SUMO), Oklahoma City, OK; Smithsonian National Museum of Natural History (SMNH), Washington, DC; California Academy of Science (CAS), San Francisco, CA; and Naturhistorisches Museum der Burgergemeinde Bern (NMBE). Bandar, and Williams are personal collections. PC1 rank and size quartiles are based on breed averages. Size quartiles are based on the distribution of neurocranium centroid sizes where “1” is smallest, “4” is largest. (XLSX) Click here for additional data file. Table S3 CanMap genotype profiles used in skull shape GWAS. The genotypes from a total of 576 CanMap dogs (105 breed-sex combinations) were matched with PC1 breed-sex phenotypes. For 75 CanMap breed-sex combinations, PC1 traits were assigned breed-sex averages. The remaining 30 breed-sex assignments were made based on PC1 data that was derived from a single breed-sex representative. Of the 30 breeds with assigned PC1 values based on single skull representatives, 17 of these had PC1 breed-sex averages for the opposite sex. Nineteen CanMap breeds used genotype data from only one sex, as craniometric data for the opposite sex was unavailable. Asterisks indicate CanMap breeds falling within the 1st and 2nd breed-sex log(neurocranium centroid) quartiles that were used in stratified analysis (Figure 2C). (XLSX) Click here for additional data file. Table S4 Associated SNPs and their p-values. SNPs listed are the top 100 associations (PLINK) or those that remained significant following correction for multiple testing (Bonferroni adjustment, GEMMA). Minor allele frequencies are based on 576 dogs from the CanMap dataset for whom we collected phenotype data. SNPs are ordered by strength of association and analysis type (GEMMA). (XLSX) Click here for additional data file. Table S5 FST intervals. For each non-allometric QTL identified by GWAS, a single marker and an interval are listed. Intervals indicate regions of contiguous or nearly contiguous blocks of sliding windows whose FST scores ranked within the top 95th percent of the distribution (FST = 0.06). The best marker within each interval is also listed. Note that CFAX.105 is not listed, as sliding windows for this QTL did not exceed the 95th percent cutoff. (XLSX) Click here for additional data file. Table S6 Haplotypes inferred by fastPHASE using CanMap genotypes. Ninety-three haplotypes with 5 or more chromosomes are listed. Alleles are color-coded relative to Haplotype 55 (Hap55), the most common haplotype identified, with matching alleles colored blue and differences colored red. Ranges in haplotype frequency (or chromosome sum, right-most column) are color-coded from blue to red, to represent low thru high values, respectively. Among extreme brachycephalic breeds, only 6 haplotypes were inferred (a haplotype unique to one Boston Terrier was omitted from the table above): Haplotypes 51, 55, 56, 65, 130, and 134. Commonality among the six haplotypes spans a 190 kb interval, from markers CFA32.8152258-CFA32.8342370. Notably, this interval extends across BMP3 and PRKG2. (XLS) Click here for additional data file. Table S7 Genetic variants discovered via alignment of whole-genome sequencing reads to the 190 kb critical interval (CFA32 markers 8152258–8342370) defined by CanMap haplotype sharing among brachycephalic breeds. Positions correspond to the CanFam2 assembly. Genotypes with quality thresholds ≤8 were reset to “0”. Green shading highlights criteria used for filtering variants. A priori knowledge indicated that causal variant(s) at the CFA32 locus must be located within a critical interval defined by allelic agreement between the Bulldog and Pekingese that were used for sequencing. As such, we reduced our critical interval to variants falling between CFA32 markers 8152258–8237937. In addition to meeting this criterion, variants earmarked “TRUE” under the column “Of potential interest” met one or more of the following criteria: 1) location within or 20 bp adjacent to an exon, 2) phastCons4way score ≥0.7, or 3) an association score (omitting Scottish terriers, see Materials and Methods) falling within the smallest 5% of P-values. In total, 48 variants met criteria listed above, including the missense mutation of BMP3 at position 8,196,098 (indicated by boldface). (XLSX) Click here for additional data file. Table S8 Dogs genotyped to verify the breakpoint at CFA32:8237937. A panel of 32 Pekingese were genotyped by Sanger sequencing using three markers: CFA32: 8196098 (the BMP3 missense mutation), CFA32:8237937 and CFA32:8296162. The latter two markers occur downstream of the breakpoint that was detected based on disagreement between the Pekingese and Bulldog whose genomes were sequenced. (XLSX) Click here for additional data file. Table S9 A survey of the BMP3 C/A transversion among 842 dogs and wolves. The BMP3F452L is caused by a C to A transversion at CFA32:8196098. A total of 113 AKC and FCI recognized breeds were genotyped by Sanger sequencing. Breeds and wolves are ordered according to PC1 rank (high = brachycephalic, low = dolichocephalic). Frequencies are given corresponding to derived (“A”) and ancestral (“C”) alleles. With the exception of Scottish Terriers and one Shetland sheepdog, all carriers of the BMP3 missense mutation rank higher than wolves for PC1. Among breeds in our allele frequency survey without morphological information (rows 77–113), six of eight carriers are assumed to be brachycephalic based on breed club descriptions (marked with asterisks). Green shading reflects allele frequencies. (XLSX) Click here for additional data file. Table S10 Primers used for sequencing and subcloning, as indicated by the last column. Name (1st column) refers to Ostrander lab primer identifiers. 5′ Tag (3rd column) refers to primer modifications used to aid sequencing or subcloning. Start and end amplicon positions are based on CanFam2 coordinates. (XLSX) Click here for additional data file.

0 comments Cited 70 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Embryology and bony malformations of the craniovertebral junction

Dachling Pang, Dominic N. P. Thompson (2010)

Background The embryology of the bony craniovertebral junction (CVJ) is reviewed with the purpose of explaining the genesis and unusual configurations of the numerous congenital malformations in this region. Functionally, the bony CVJ can be divided into a central pillar consisting of the basiocciput and dental pivot and a two-tiered ring revolving round the central pivot, comprising the foramen magnum rim and occipital condyles above and the atlantal ring below. Embryologically, the central pillar and the surrounding rings descend from different primordia, and accordingly, developmental anomalies at the CVJ can also be segregated into those affecting the central pillar and those affecting the surrounding rings, respectively. Discussion A logical classification of this seemingly unwieldy group of malformations is thus possible based on their ontogenetic lineage, morbid anatomy, and clinical relevance. Representative examples of the main constituents of this classification scheme are given, and their surgical treatments are selectively discussed.

0 comments Cited 42 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

The genetics of canine skull shape variation.

Jeffrey J. Schoenebeck, Elaine Ostrander (2013)

A dog's craniofacial diversity is the result of continual human intervention in natural selection, a process that began tens of thousands of years ago. To date, we know little of the genetic underpinnings and developmental mechanisms that make dog skulls so morphologically plastic. In this Perspectives, we discuss the origins of dog skull shapes in terms of history and biology and highlight recent advances in understanding the genetics of canine skull shapes. Of particular interest are those molecular genetic changes that are associated with the development of distinct breeds.

0 comments Cited 41 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Claire Wade: Role: Editor

Journal

Journal ID (nlm-ta): PLoS One

Journal ID (iso-abbrev): PLoS ONE

Journal ID (publisher-id): plos

Journal ID (pmc): plosone

Title: PLoS ONE

Publisher: Public Library of Science (San Francisco, USA )

ISSN (Electronic): 1932-6203

Publication date Collection: 2014

Publication date (Electronic): 12 February 2014

Volume: 9

Issue: 2

Electronic Location Identifier: e88120

Affiliations

[1 ]Neurology Department, Fitzpatrick Referrals, Godalming, Surrey, United Kingdom

[2 ]akm-stats, Glasgow, Scotland, United Kingdom

[3 ]Department of Small Animal Medicine & Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America

[4 ]Department of Neurosciences, Justine University Hospital Research Center, University of Montreal, Quebec, Canada

[5 ]School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom

University of Sydney, Australia

Author notes

* E-mail: cmsmindicators@ 123456gmail.com

Competing Interests: We have the following interests: Clare Rusbridge is employed by Fitzpatrick Referrals and the University of Surrey and Susan P Knowler works voluntarily and is affiliated with Fitzpatrick Referrals. Angus K McFadyen is an independent statistical consultant operating professionally as a sole trader under the company name of akm-stats. There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Conceived and designed the experiments: SPK CR. Performed the experiments: SPK CR. Analyzed the data: SPK AKM. Contributed reagents/materials/analysis tools: ZK CF MK SRP AKM SPK CR. Wrote the paper: SPK CR AKM. Contributed to the original concept of a QTL analysis: ZK.

Article

Publisher ID: PONE-D-13-24984

DOI: 10.1371/journal.pone.0088120

PMC ID: 3922758

PubMed ID: 24533070

SO-VID: 8bc6ae5e-4dc7-4426-aff5-f6b28b82c3bf

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

History

Date received : 16 June 2013

Date accepted : 4 January 2014

Page count

Pages: 13

Funding

Contributions towards the cost of magnetic resonance imaging for most of the dogs in this study were made by the following organizations or individuals: Syringomyelia DNA Research ( http://www.veterinary-neurologist.co.uk/Syringomyelia/DNA_Research/); American Kennel Club Canine Health Foundation Grant #1004; The Griffon Bruxellois Club 1897; For the Love of Ollie Fund; Friends of Lola Fund and Lee and Frank Pieterse. The Canadian Institutes of Health Research and Cavalier Matters Charity Reg No 1141674 contributed towards the cost of leasing the DICOM viewing software package MIMICS 14.12 Materialise (Technologielaan 15 3001 Leuven Belgium). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Quantitative Analysis of Chiari-Like Malformation and Syringomyelia in the Griffon Bruxellois Dog

Read this article at

Abstract

Related collections

Core Readings in Statistical Mediation Analysis

Most cited references 31

Variation of BMP3 Contributes to Dog Breed Skull Diversity

Embryology and bony malformations of the craniovertebral junction

The genetics of canine skull shape variation.

Author and article information

Contributors

Journal

Affiliations

Author notes

Article

History

Page count

Funding

Categories

Comments

Comment on this article

Similar content 1,000

Cited by 18

Most referenced authors 567