1,720,963 research outputs found
Quantifying the effect of Warmblood Fragile Foal Syndrome on foaling rates in the German riding horse population
No full textAwareness of breeders of Warmblood Fragile Foal Syndrome (WFFS) increased after a widely discussed case in the USA in 2018. The hereditary connective tissue disorder, first described by a US research group in 2011 and for which a commercial genetic test exists since 2013, is caused by a point mutation in the PLOD1 gene, inherited autosomal recessively. Extension of molecular genetic testing and reporting of test results of organized horse breeders to their studbooks implies new opportunities for analyses. In Germany, data are centrally accessible through the integrated equine data base allowing comprehensive and population-wide investigation of the role of WFFS. The objective of this study was statistical testing for associations between WFFS and reproductive performance of German riding horses and quantifying possible differences between WFFS carriers and non-carriers, also in respect of performance traits. For this purpose, covering data from 2008 to 2020 were provided by ten German studbooks, so almost 400,000 coverings and resulting foaling rates were available for multiple analyses of variance with general and mixed linear models using procedures GLM, MIXED and HPMIXED of SAS software (version 9.2). Published breeding values of stallions were used for respective comparisons of riding horse performance. Assuming a WFFS carrier frequency of 9.5–15.0% in Warmblood horses, Hardy Weinberg principle implied an expected difference of 2.4–3.7% in the foaling rates of carrier and non-carrier stallions. Our results provided statistical evidence of detrimental effects of WFFS on the reproductive performance of Warmblood horses with about 2.7% lower average foaling rate in carriers of the mutant allele than in WFFS free sires, if mated to an average mare population. Indications of favorable dressage performance of WFFS carriers were found. Reported WFFS cases indicate only the tip of the iceberg and assessing the impact of WFFS on reproduction requires consideration of premature foal losses
Change in parentage control in Warmblood horses with an outlook into future genomic applications for horse breeding
No full textIn der deutschen Warmblutpferdezucht existiert die Bestrebung, nach der konventionellen auch die genomische Zuchtwertschätzung (gZWS) zu etablieren. Einen zusätzlichen Schritt bei der Nutzung genomischer Informationen stellt die Umstellung der Abstammungskontrolle über die Typisierung von Mikrosatelliten (MS) auf die Single Nucleotide Polymorphism (SNP)-Technologie dar. Für den Übergang zwischen beiden Verfahren bietet die Imputation von MS-Allelen basierend auf SNP-Daten einen effizienten, kostensparenden Ansatz. In einer zehnfachen Kreuzvalidierung wurde erprobt, ob sich die Imputation über Pferderassen hinweg, innerhalb von Rassen oder innerhalb von Gruppen genetischer Ähnlichkeit (Clustern) besser eignet. Dafür standen 2.607 Stuten zur Verfügung, die für bis zu 17 MS und über 70.000 SNPs genotypisiert waren und den Rassen Holsteiner, Westfale, Oldenburger, Oldenburg International und Trakehner zugehörig waren. In allen drei Ansätzen wurden durchschnittliche Imputationsgenauigkeiten von über 89% erreicht, wobei für MS mit einer Genotypisierungsrate über 90% Genauigkeiten von über 96% erreicht wurden. Neben der Abstammungskontrolle und der gZWS bietet die Verfügbarkeit genomischer Informationen weitere Anwendungen, wie beispielsweise Populationsmonitoring, Diversitätsmanagement und die Aufklärung von genetisch verursachten Krankheiten und Letalvarianten
Replacement of microsatellite markers by imputed medium-density SNP arrays for parentage control in German warmblood horses
No full textIn horses, parentage control is currently performed based on an internationally standardized panel of 17 microsatellite (MS) markers comprising 12 mandatory and five optional markers. Unlike MS, single nucleotide polymorphism (SNP) profiles support a wider portfolio of genomic applications, including parentage control. A transition to SNP-based parentage control is favorable, but requires additional efforts for ensuring generation-overlapping availability of marker genotypes of the same type. To avoid double genotyping of either parents or offspring for changing to SNP technology and enable efficient transition, we tested whether MS genotypes used for parentage control could be reliably imputed from a medium-density SNP panel in German warmblood horses. Imputation accuracy was tested in a tenfold cross-validation with two approaches: within breed (option A) and across breeds (option B). Average imputation accuracies of 97.98% (A) and 96.17% (B) were achieved, respectively. Due to interbreed differences in genotyping rates, five MS markers of low genotyping rate (GTR; < 90%) could be imputed with higher accuracy within breed (98.18%) than across breeds (90.73%). MS markers with high GTR performed homogeneously well in option B (98.44%) and showed slightly lower accuracy in option A (97.90%). Among these markers, AHT5 proved to be problematic for imputation regardless of the approach, revealing accuracies of 86.40% (A) and 88.70% (B). Better results for MS markers with high GTR and savings in computational processing justified the choice of option B for routine implementation. To date, more than 9500 horses have undergone the new parentage control based on imputed MS genotypes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13353-022-00725-9
Change in parentage control in Warmblood horses with an outlook into future genomic applications for horse breeding
No full textIn der deutschen Warmblutpferdezucht existiert die Bestrebung, nach der konventionellen auch die genomische Zuchtwertschätzung (gZWS) zu etablieren. Einen zusätzlichen Schritt bei der Nutzung genomischer Informationen stellt die Umstellung der Abstammungskontrolle über die Typisierung von Mikrosatelliten (MS) auf die Single Nucleotide Polymorphism (SNP)-Technologie dar. Für den Übergang zwischen beiden Verfahren bietet die Imputation von MS-Allelen basierend auf SNP-Daten einen effizienten, kostensparenden Ansatz. In einer zehnfachen Kreuzvalidierung wurde erprobt, ob sich die Imputation über Pferderassen hinweg, innerhalb von Rassen oder innerhalb von Gruppen genetischer Ähnlichkeit (Clustern) besser eignet. Dafür standen 2.607 Stuten zur Verfügung, die für bis zu 17 MS und über 70.000 SNPs genotypisiert waren und den Rassen Holsteiner, Westfale, Oldenburger, Oldenburg International und Trakehner zugehörig waren. In allen drei Ansätzen wurden durchschnittliche Imputationsgenauigkeiten von über 89% erreicht, wobei für MS mit einer Genotypisierungsrate über 90% Genauigkeiten von über 96% erreicht wurden. Neben der Abstammungskontrolle und der gZWS bietet die Verfügbarkeit genomischer Informationen weitere Anwendungen, wie beispielsweise Populationsmonitoring, Diversitätsmanagement und die Aufklärung von genetisch verursachten Krankheiten und Letalvarianten
Genetic and genomic characterization followed by single-step genomic evaluation of withers height in German Warmblood horses
Full text linkAbstract Reliability of genomic predictions is influenced by the size and genetic composition of the reference population. For German Warmblood horses, compilation of a reference population has been enabled through the cooperation of five German breeding associations. In this study, preliminary data from this joint reference population were used to genetically and genomically characterize withers height and to apply single-step methodology for estimating genomic breeding values for withers height. Using data on 2113 mares and their genomic information considering about 62,000 single nucleotide polymorphisms (SNPs), analysis of the genomic relationship revealed substructures reflecting breed origin and different breeding goals of the contributing breeding associations. A genome-wide association study confirmed a known quantitative trait locus (QTL) for withers height on equine chromosome (ECA) 3 close to LCORL and identified a further significant peak on ECA 1. Using a single-step approach with a combined relationship matrix, the estimated heritability for withers height was 0.31 (SE = 0.08) and the corresponding genomic breeding values ranged from − 2.94 to 2.96 cm. A mean reliability of 0.38 was realized for these breeding values. The analyses of withers height showed that compiling a reference population across breeds is a suitable strategy for German Warmblood horses. The single-step method is an appealing approach for practical genomic prediction in horses, because not many genotypes are available yet and animals without genotypes can by this way directly contribute to the estimation system.Abstract Reliability of genomic predictions is influenced by the size and genetic composition of the reference population. For German Warmblood horses, compilation of a reference population has been enabled through the cooperation of five German breeding associations. In this study, preliminary data from this joint reference population were used to genetically and genomically characterize withers height and to apply single-step methodology for estimating genomic breeding values for withers height. Using data on 2113 mares and their genomic information considering about 62,000 single nucleotide polymorphisms (SNPs), analysis of the genomic relationship revealed substructures reflecting breed origin and different breeding goals of the contributing breeding associations. A genome-wide association study confirmed a known quantitative trait locus (QTL) for withers height on equine chromosome (ECA) 3 close to LCORL and identified a further significant peak on ECA 1. Using a single-step approach with a combined relationship matrix, the estimated heritability for withers height was 0.31 (SE = 0.08) and the corresponding genomic breeding values ranged from − 2.94 to 2.96 cm. A mean reliability of 0.38 was realized for these breeding values. The analyses of withers height showed that compiling a reference population across breeds is a suitable strategy for German Warmblood horses. The single-step method is an appealing approach for practical genomic prediction in horses, because not many genotypes are available yet and animals without genotypes can by this way directly contribute to the estimation system
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Single-step genomic evaluation for linear conformation and performance traits for German riding horses
No full textDie Implementierung eines genomischen Zuchtwertschätzverfahrens für die Pferdezucht stellt eine Herausforderung dar, wobei kollaborative Ansätze die erforderliche Erstellung einer ausreichend großen und aussagekräftigen Lernstichprobe erleichtern. In Deutschland ermöglichte die Zusammenarbeit von fünf Pferdezuchtverbänden, bis Ende 2020 eine Lernstichprobe mit dem Fokus auf Linearmerkmalen des Exterieurs und der Leistung aufzubauen. Für die Entwicklung eines Prototyps zur genomischen Zuchtwertschätzung (gZWS) kam das sogenannte Single-Step-Verfahren zum Einsatz, bei dem sämtliche verfügbaren Daten zu Phänotypen, Genotypen und Pedigree eingehen und die Aussagekraft der Schätzung maximieren. Die Validierung des gZWS-Prototyps erfolgte mittels zweier Ansätze, die konsistente Ergebnisse lieferten. So wurden in der zehnfachen Kreuz-Validierung und in der Vorwärts-Validierung Korrelationen zwischen den genomischen Zuchtwerten (gZW) der jeweiligen Validierungsläufe und des Gesamtlaufs im mittleren (0,6) bis hohen (über 0,9) Bereich erzielt. Beim überwiegenden Anteil der Merkmale lagen die Korrelationen über 0,85, was unter Berücksichtigung der verfügbaren Datengrundlage für eine zufriedenstellende Stabilität des entwickelten Systems spricht, jedoch gewisse Änderungen der gZW in aufeinanderfolgenden Schätzläufen erwarten lässt. Unterschiede zwischen den einbezogenen Rassen waren bei der Kreuzvalidierung auszumachen, fielen jedoch gering aus. Die Nutzung der Genotypdaten und Schätzung anhand der genomischen Verwandtschaftsmatrix führte zu einer deutlicheren Differenzierung zwischen den Pferden, was für eine größere Nähe der gZW zur wahren individuellen genetischen Veranlagung sprechen kann. Innerhalb der Gruppe der linear beschriebenen Pferde der Geburtsjahre 2007–2017, aus denen sich 98% der Lernstichprobepferde rekrutierten, ließ sich der Mehrwert der Einbindung genomischer Information aufzeigen. Bei den genotypisierten Pferden waren die Korrelationen zwischen den gZW aus Vorausschätzung und Gesamtlauf höher (+0,03 bis + 0,26) und die Streuung der gZW größer (Standardabweichung > +2,0) als bei den nicht genotypisierten Pferden. In Übereinstimmung mit vorangegangenen Untersuchungen zum Merkmal Körpergröße ergab diese Arbeit keine Ergebnisse, die die Umsetzbarkeit der gZWS im Single-Step-Verfahren für lineare Exterieur- und Leistungsmerkmale auf der Grundlage einer gemischten Lernstichprobe für die deutsche Reitpferdezucht in Frage stellen. Weitere Kalibrierungen sind erforderlich, um sie zeitnah als Routineverfahren einführen zu können
- …
