Creation Of Breeds Research Articles

SNP-based genetic signatures revealed breeding effects in indigenous Livni compared with Landrace and Large White breeds

Livni is one of the Russian local pig breeds. We previously reported that this breed was more distinct from Duroc breed than from Landrace and the Large White breeds, which participated in the Livni breed creation. The aim of the study was to determine the SNP-based genetic signatures in fat-type Livni breed shared with commercial Landrace and the Large White breeds, and ones that are affected by putative selection.
 The genome-wide SNP genotyping was carried out using the Porcine GGP HD BeadChip, which contains ~ 80 000 SNPs.
 Obtained breed relationship and admixture results indicated the insignificant participation of the Landrace and the Large White breeds in the formation of the modern allelofund of Livni pigs. 238 candidate genes were found in the genomic regions with selection signatures, 182 genes with described functions were identified. In the Livni and Landrace breeds, 35 common genes were detected which formed one cluster with enrichment coefficient = 4.94 and predominant HOXD genes. In the Livni and Large White breeds, the largest amounts of common genes were detected (62 in average), which formed two clusters. Cluster 1, with enrichment coefficient = 2.11, was characterized with genes involved in glucose metabolism. Cluster 2, with enrichment coefficient = 1.60, demonstrated helicase genes. Annotated clusters were not determined for the Livni breed. However, 50 candidate genes were specific to Livni pigs and associated with various growth, carcass and reproductive traits, essential for thermoregulation. 
 Results revealed common SNP-based genetic signatures and breeding effects in indigenous Livni compared with Landrace and Large White breeds.

Creation of heat-resistant, high-product breeds and hybrids of mulberry silkworm (Bombyx mori l.)

In the current era of highly developed science, technology and technology, the demand for natural fabrics is increasing year by year in the world market, and the world silk industry and science are led to the cultivation of mulberry varieties with high nutritional value and the creation of breeds and hybrids suitable for different seasons of the changing external environment. In recent years, in the Republic of Uzbekistan, the practice of rearing mulberry silkworms several times a year has been used. However, there are no breeds and hybrids suitable for the hot summer conditions of our country, based on this, scientific research has been started in the direction of creating heat-resistant breeds at the Silk Research Institute. In this article, the results of the breeding of 6 breeds and 4 different industrial hybrids of mulberry silkworm under hot conditions are described. Based on preliminary data, Line 1 and Line 2 systems were found to have high embryonic and post-embryonic viability under hot summer conditions. However, the average cocoon weight of these systems was 1.68-1.73 g, cocoon shell weight was 339 mg, and cocoon silkiness was 19.6-20.2%. Based on the obtained results, it was concluded that Line 1 and Line 2 systems can be used as initial selection material for creating heat resistant breeds.

Use of a new breeding methods for creation of breeds with desired properties and traits

Use of a new breeding methods for creation of breeds with desired properties and traits

Methods and stages of creation and practical use of red white-belt meat pigs

It is known that the peoples of different countries and continents have always sought knowledge, enrichment of their culture and improving living standards. But no matter how the world is broken, no matter how the system is built - food has been and will always remain the first ingredient of independence and development of any state.
 And if there are alternative solutions in overcoming other topical and economically important problems, there are no alternative ones in the implementation of food issues. Almost everyone knows that one of the main indicators of human quality is the use of animal protein. In the developed countries of the world it is consumed on average per capita in the range of 52-56 g per day, which is good, but below the scientifically sound dietary norms. As for developing countries, this figure is 12-16 g, that is 4-5 times less than the norm. According to statistics, in recent years the world has produced approximately 342 million tons of meat annually, of which about 36.4% was poultry, 35.2% - pork, 21.8% - beef, 4.4 % - lamb and goat and 2, 2% for other species. According to experts, pork will remain in the lead. And why is this so? But thanks to the extremely important biological and economic characteristics of pigs: multiplicity, precocity, omnivorous, economical use of feed, unpretentiousness to the conditions of detention, as well as the ability to cook pork many different delicious dishes. [1]. In Ukraine, pig farming has long been considered, so to speak, a national branch of agricultural production and has almost never been unprofitable for a caring owner. There was a time when pork accounted for 58.7 percent of total meat production. Long-term observations record periods of intensive development of pig breeding and its catastrophic decline. And yet, despite periodic economic cataclysms, focused research on the theory and practice of the industry continued, and the painstaking long-term work of pig scientists and practitioners, as a rule, ended with the latest advances. Long-term observations record periods of intensive development of pig breeding and its catastrophic decline. And yet, despite periodic economic cataclysms, focused research on the theory and practice of the industry continued, and the painstaking long-term work of pig scientists and practitioners, as a rule, ended with the latest advances.
 In order to maintain this fact, we recall that in all farms of Ukraine in 1913 there were 8.5 million pigs; in 1940–9.2; in 1944–2.9; in 1950 –7.0; in 1971–21.4 million heads, it should be added that in 1989 the country produced 1,576,000 tons of pork at slaughter weight, or 31 kg per capita, which fully complied with existing scientifically sound medical standards of human nutrition. [3]. Unfortunately, it should also be noted that at the beginning of 2022 the number of pigs in the country does not exceed 8 million.
 It is known that the direction of pig productivity is determined by the social order in the period of creation of breeds, as well as the place of their use in regional breeding systems. Thus, the breeds that were bred in our country in the 40-60 years of the last century, were characterized mainly by a well-defined sebaceous direction of productivity. This can be confirmed by the creation of Ukrainian steppe white, Myrhorod and Ukrainian steppe speckled rocks. In the following decades, with the increase in demand for pork, the improvement of previously created breeds was carried out in the direction of improving the meat of carcasses, reducing the fattening period and reducing costs per unit of growth without deteriorating pork quality. [2]. Due to the lack of domestic meat genotypes, a special role in crossbreeding and hybridization was given to the breeds of Landrace, Pietren, Duroc, Wales and Hampshire imported from abroad. However, imported breeds, firstly, were unable to meet the high needs of our pigs in high-quality meat boar herds and, secondly, the efficiency of importing breeding stock was low due to its slow adaptation to different climatic conditions. and economic features of our then very large state. Therefore, it is expedient to breed new domestic genotypes of pigs, which would meet the demand of mass pig breeding in the meat population and reduce the pressure of imports on the domestic market of breeding pigs.
 In accordance with the above, in the eighties of the last century Poltava Research Institute of Pig breeding began work to create a new genotype (breed) of pigs, which would be characterized by good reproductive ability, high fattening and meat qualities, and which could be used as a parent shape in combination with existing breeds and their mixtures. The work to create a new parent breed was relevant and had economic significance. [3].

Genetic Variability and Population Structure of the Tunisian Sicilo-Sarde Dairy Sheep Breed Inferred from Microsatellites Analysis.

This study analyzed the genetic variability, inbreeding and population structure of the Tunisian–North African dairy sheep breed, the Sicilo-Sarde (SS), created by crossing the Sarda and Comisana dairy breeds. The level of variability in the SS, considered as an endangered breed after a dramatic decrease, was assessed using 17 microsatellite markers by analyzing the two breed populations sampled from their respective cradles: SS of Beja (SSB, n = 27) and SS of Mateur (SSM, n = 25). High levels of genetic diversity in SS were revealed, with a total of 212 alleles, a high mean number of alleles (12.47 ± 4.17) and a high average polymorphism information content (PIC) (0.81 ± 0.10). The observed heterozygosity was considerable in SSB and SSM (0.795 and 0.785, respectively). The inbreeding level measured by the population inbreeding coefficient FIS is higher in the SSM population (0.121) than in the SSB population (0.090). The higher genetic diversity level detected in SSB reflected the effect of new Italian Sarda genes introduced by intra-uterine artificial insemination recently practiced in this population. The Wilcoxon test and the mode-shift distribution indicated that the SS breed is a non-bottlenecked population. The structural analysis reflected the historical miscegenation practiced during the breed creation and highlighted further ancient miscegenation, which could date back to the first waves of sheep introduction to the western Mediterranean region. Microsatellite markers were successfully applied in the assessment of the genetic variability of SS and should be used in monitoring this variability during the application of conservation strategies.

Breed as a biotechnological phenomenon

Authors of this article discuss about the problem of developing the theoretical foundations of animal domestication (including the creation of breeds) in modern biological science. Unfortunately, at the moment, the issue under consideration, which is located at the intersection of such scientific disciplines as zoology, biotechnology, veterinary medicine and animal science, in the Russian Federation is insufficiently studied and generalized theoretically. In addition, the analysis of the use and interpretation of the term «breed» is carried out on the example of the current situation in Russian agriculture. The processes of creating and using breed standards are also considered. Our own experience demonstrates that the creation of a reasoned and complex teaching about the breed as a biological and technological phenomenon will significantly improve the quality of veterinary and zootechnical education and fundamental biological science.

Interspecific sexual selection, a new theory for an old practice: the increase of artificial biodiversity through creation of modern, standardized breeds

Darwin set the pillars of organismic evolution when he defined natural and sexual selection in the 19th century. Concurrently, a frenzy of selective breeding programmes, generally supported by the wealthy and aristocratic, gave rise to novel breeds of plants and animals at a rate that was previously unforeseen. Since then, breeds selected over millennia and adapted to local conditions began to disappear or were threatened with extinction, being substituted by these new, standardized breeds. It is of interest to explore how new breeds emerged and what the main criteria of the founders of these breeds were. Darwin seemed to be unaware that his contemporaries were practicing a form of interspecific sexual selection responsible for the fixation of exaggerated traits, often plainly ornamental, in the new breeds they intended to create. Parent animals were chosen by individuals who were following particular goals, often with aesthetic criteria in mind. Here we investigated who were the founders of modern breeds in five domesticated species (dogs, cats, pigs, horses and cattle), as very often a single person is credited with the creation of a breed. We found information on founders of 459 breeds, 270 of which were created after 1800. Interestingly, for these species, breed creation is overwhelmingly attributed to men. In the wild, however, the choice of mate is usually performed by the female of a species and thought to be adaptive. Breeders in the Victorian era, nevertheless, lacked such adaptive skills and had little scientific knowledge. The selection of individuals with an extreme expression of the desired traits were often close relatives, resulting in high inbreeding and a variety of genetic disorders.

Results of creating a new breed of fat-tailed sheep with white and light gray wool

Relevance. The demand increase in the domestic and foreign markets for high-quality, environmentally clean lamb, as well as for coarse, clarified wool, especially in scarce white and light gray colors, fur sheepskin, determines the relevance of the scientific support of domestic fat-tailed sheep breeding. Material and methods. The article represents the results of the studies on the new breed creation of fat-tailed meat-greasy sheep in the eastern, south-eastern and western regions of Kazakhstan. Results. New breed animals successfully combine high meat quality with heterogeneous white and light gray wool, are well adapted to grazing conditions in desert, semi-desert and foothill-dry steppe zones. The average live weight of sheep producers of breeding herds, depending on the breeding farms, is 95.4–97.8 kg, sheared wool — 3.34–3.38 kg, for ewes — 66.0–66.8 and 2, respectively. 28–2.32 kg. The average live weight of ram lambs at birth varies between 4.8–5.0 kg and 37.7–38.6 kg when chopping, the average daily live weight gain during the suckling period of development is 274–280 g, for the ewe lambs these indicators are equal to 4.6–4.8 kg, 36.0–36.7 kg and 262–266 g, respectively. At the age of 4 months, the mass of carcass with fat tail of the created sheep breed is 18.49–19.03 kg, at 16 months — 33.46–33.77 kg, slaughter yield ranges from 52.3–53.1 and 52.5–52.9%, respectively, pulp yield in the carcass is 79.3–79.8 and 80.2–80,6%. These data show that in terms of slaughter and meat qualities, rams of the newly created sheep breed are not inferior to peers of such breeds as Edilbay, Saryarka, etc. The studies conducted in the wool laboratory of Sheep Breeding Research Institute named after K.U. Medeubekova, showed that the clarified sheep wool of the created breed has some physical and mechanical differences in comparison with the Kazakh fattailed coarse-haired sheep. Their wool can be attributed to a new variety sheep breed of coarse-wooled sheep in Kazakhstan. Such wool has better technological properties in comparison with the fat-tailed coarse-wooled sheep.

ACADEMICIAN V. P. BURKAT – RECOGNIZED SCIENTIST IN ANIMAL BREEDING, AGRICULTURAL SCIENCE ORGANIZER, PUBLIC FIGURE

The authors have argued that doctor of agricultural sciences, professor and academician of Ukrainian Academy of Agrarian Sciences V. P. Burkat made a significant contribution to the development of agricultural science in Ukraine as an outstanding scientist in the field of animal breeding, organizer of agricultural research work, public figure. His greatest achievement is development of the conceptual aspects of breed formation in cattle-breeding, which was implemented in creation of a few highly specialized cattle breeds. The scientist is co-author of the first created in Ukraine Ukrainian Red-and-White Dairy, Ukrainian Black-and-White Dairy, Ukrainian Red Dairy, Ukrainian Brown Dairy, Volyn Beef, Polesian Beef, Southern Beef breeds and their structural units (interbreed types, lines and families).
 The article shows that the scientist substantiated the feasibility of comprehensive genetic monitoring as one of the main conditions in creating new and improving existing breeds of cattle. He developed biotechnological and genetic principles of farm animal breeding. He laid foundation of a new comprehensive science – biotech breeding, identified the main components of its structural status and applied new theoretical approaches to the selection process, taking into account the practical use of biotechnological methods. The scientist first raised ethical, social and legal aspects of introduction of biotechnology in agriculture.
 V. P. Burkat`s achievement is development of the theory of conservation of the gene pool of farm animals. He initiated development of concept of gene objects creation and placing, defined their purpose in the system of conservation of the farm animal breeding resources. He explained importance of the gene pool banks as the main link of farm animal conservation.
 The authors have proven that scientific heritage of academician V. P. Burkat didn`t lose its importance and relevance in the current development of animal husbandry. Some parts of it, including the theory of breed creation; methodical bases of management of breed genealogy; theory of consolidation of breed units; bases of breeding, evaluation and sustainable use of sires; genetic, biotechnological and technological bases of selection; methods of conservation and sustainable use of animal gene pool should be used as a theoretical and methodological basis for development of further strategies in cattle breeding.
 Academician V. P. Burkat is prominent organizer of agricultural research work in animal husbandry of Ukraine. He made significant efforts to obtain status of main methodological and coordination center of agriculture of Ukraine by Ukrainian Academy of Agrarian Sciences. Almost 30 years he devoted to the establishment of branch guidance and coordination center – Institute of Animal Breeding and Genetics. One of the most important achievements of scientist was organization of scientific school "Breeding and Biotechnology in Animal Husbandry" at Institute of Animal Breeding and Genetics in 1980. His disciples are famous scientists, including academicians of NAAS M. Baschenko, V. Ladyka, Yu. Melnik, corresponding members of the NAAS S. Ruban, S. Kovtun, doctor of agricultural sciences A. Havruk, V. Antonenko, S. Voitenko, A. Dubin, V. Smetanin, V. Dzitsyuk, Yu. Polupan, K. Kopylov and others.
 The article shows that V. P. Burkat is known public figure who defended the national idea at all levels of exposure, as a co-founder of the historical-biographical series "Ukrainian Agrarian Scientists of the Twentieth Century", initiator of a number of encyclopedic, reference and bibliographic publications, editor of scientific journals, author of fundamental scientific generalizing papers and others.

Similar genomic proportions of copy number variation within gray wolves and modern dog breeds inferred from whole genome sequencing

BackgroundWhole genome re-sequencing data from dogs and wolves are now commonly used to study how natural and artificial selection have shaped the patterns of genetic diversity. Single nucleotide polymorphisms, microsatellites and variants in mitochondrial DNA have been interrogated for links to specific phenotypes or signals of domestication. However, copy number variation (CNV), despite its increasingly recognized importance as a contributor to phenotypic diversity, has not been extensively explored in canids.ResultsHere, we develop a new accurate probabilistic framework to create fine-scale genomic maps of segmental duplications (SDs), compare patterns of CNV across groups and investigate their role in the evolution of the domestic dog by using information from 34 canine genomes. Our analyses show that duplicated regions are enriched in genes and hence likely possess functional importance. We identify 86 loci with large CNV differences between dogs and wolves, enriched in genes responsible for sensory perception, immune response, metabolic processes, etc. In striking contrast to the observed loss of nucleotide diversity in domestic dogs following the population bottlenecks that occurred during domestication and breed creation, we find a similar proportion of CNV loci in dogs and wolves, suggesting that other dynamics are acting to particularly select for CNVs with potentially functional impacts.ConclusionsThis work is the first comparison of genome wide CNV patterns in domestic and wild canids using whole-genome sequencing data and our findings contribute to study the impact of novel kinds of genetic changes on the evolution of the domestic dog.

INBREEDING IN THE MIRGORODIAN PIGS

The problem of inbreeding in livestock, which is directly related to breed creation, the improvement of breeding methods and the preservation of the gene pool of populations, although highlighted in the works of many researchers, has no logical conclusion to date. Biologists, geneticists and breeders cannot give an unambiguous answer to the question of the effectiveness of the use of related breeding in livestock, although it is common knowledge that inbreeding was one of the main means of breeding work for the creation of cultivars of farm animals in the world.
 It is impossible to make a single conclusion about the positive or negative effects of related breeding. Probably the effect of a related breeding does not depend on the inbreeding itself but on the animal on which it is applied, and on the degree of homozygosity of inbred animals. While the growth of inbreeding did not exceed the optimal homozygosity for a certain kinds, it is possible to obtain high-yielding individuals that consistently transmit hereditary signs to offspring. Undeniable can also be considered the use of this method in the creation of new lines, types and breeds, the detection of hidden alleles, the consolidation of animals, etc. However the smaller the population in terms of the number of individuals and, first of all in the number of pedigrees, the use of related breeding will result in loss of heterozygosity and the creation of an inbred genotype. That is why the constant control of animal productivity, especially low-inheritance traits, in a small number of pedigrees in local populations and the presence of inbred animals, is an urgent problem of the present.
 The purpose of our research was to determine the number of inbred sows of the mirgorodian breed in general on the breed and directly in each of the available families, the coefficients of inbreeding, as well as the effect of inbreeding on the number of emergency farms and multiplicity of the uterus.
 Studies were conducted on stems of the mirgorodian breed. Our research has established that mirgorodian breed of pigs is concentrated in only one breeding plant in Ukraine. Genealogical structure of the herd consists of 11 families of sows (150 main sows) and 7 lines of boars (13 main boars). Moreover, the number of animals in the herd is constantly reduced. When breeding pigs of mirgorodian breed of this herd during the last 10–20 years, a selection of mutters and uterus belonging to different lines was used to avoid the related breeding. In order to reduce the number and probability of occurrence in the flock of inbred animals, breeders, when developing a parry plan, select the stumps and moths that are not related to each other within the first to third generation.
 Our researches found that among the 165 analyzed sows of mirgorodian breed of 11 available families, the number of outbred individuals is 52%, and inbreds – 48% for the different ratio of inbred and outbred mothers within families.
 Determined complex inbreeding of sows of mirgorodian breed testifies that the investigated female individuals of this population are inbred in degree 0,78–10,1%. At the same time, the vast majority of inbred mothers do not have a high homozygosity coefficient of 1.56–2.34%, and only single animals are inbred at a rate of 6.25–10.1%. Inbred sows of the mirgorodian breed, without their distribution by degree of inbreeding, had a lower number of emergency farms, as compared with outbred ones, as a whole in the group of animals, and in the context of families.
 The positive aspect of the inbred sows of mirgorodian breed was also somewhat higher infertility in the average for a number of farrowing in the families – 10,2 heads, compared with outbreds, in which this figure was at 9,9 points. From what it is possible to draw a conclusion about the positive influence of inbreeding not a high degree of tightness – not higher than 10%, on indicators of reproductive ability of sows of mirgorodian breed.

Ancient European dog genomes reveal continuity since the Early Neolithic

Europe has played a major role in dog evolution, harbouring the oldest uncontested Palaeolithic remains and having been the centre of modern dog breed creation. Here we sequence the genomes of an Early and End Neolithic dog from Germany, including a sample associated with an early European farming community. Both dogs demonstrate continuity with each other and predominantly share ancestry with modern European dogs, contradicting a previously suggested Late Neolithic population replacement. We find no genetic evidence to support the recent hypothesis proposing dual origins of dog domestication. By calibrating the mutation rate using our oldest dog, we narrow the timing of dog domestication to 20,000–40,000 years ago. Interestingly, we do not observe the extreme copy number expansion of the AMY2B gene characteristic of modern dogs that has previously been proposed as an adaptation to a starch-rich diet driven by the widespread adoption of agriculture in the Neolithic.

Теоретичні та методологічні аспекти виведення першої м’ясної породи в УРСР

Автором поставлено мету – висвітлити внесок доктора сільськогосподарських наук, професора М. А. Кравченка (1908–1986) у становлення і розвиток галузі спеціалізованого м’ясного скотарства в УРСР в 50–80-ті роки ХХ ст. Узагальнено розроблену ним програму та методику виведення чернігівського і придніпровського внутрішньопородних типів, а також української м’ясної породи. Встановлено, що окремі положення методики покладено в основу створення інших порід і типів м’ясної худоби, які за генетичним потенціалом продуктивності відповідають рівню європейських стандартів, а за своїми біологічними характеристиками – вимогам регіонального розведення в умовах України. Показано, що проблема становлення і розвитку галузі вітчизняного м’ясного скотарства знаходилася в центрі уваги учнів і послідовників М. А. Кравченка. Охарактеризовано сучасну критичну ситуацію, що склалася з генофондом м’ясних порід в Україні, способи оптимізації їх чисельності та продуктивності за умов чистопородного розведення і міжпородного схрещування. Доведено, що наукові розробки вченого не втратили своєї актуальності і значущості на сучасному етапі розвитку галузі.

Inferring Population Size History from Large Samples of Genome-Wide Molecular Data - An Approximate Bayesian Computation Approach.

Inferring the ancestral dynamics of effective population size is a long-standing question in population genetics, which can now be tackled much more accurately thanks to the massive genomic data available in many species. Several promising methods that take advantage of whole-genome sequences have been recently developed in this context. However, they can only be applied to rather small samples, which limits their ability to estimate recent population size history. Besides, they can be very sensitive to sequencing or phasing errors. Here we introduce a new approximate Bayesian computation approach named PopSizeABC that allows estimating the evolution of the effective population size through time, using a large sample of complete genomes. This sample is summarized using the folded allele frequency spectrum and the average zygotic linkage disequilibrium at different bins of physical distance, two classes of statistics that are widely used in population genetics and can be easily computed from unphased and unpolarized SNP data. Our approach provides accurate estimations of past population sizes, from the very first generations before present back to the expected time to the most recent common ancestor of the sample, as shown by simulations under a wide range of demographic scenarios. When applied to samples of 15 or 25 complete genomes in four cattle breeds (Angus, Fleckvieh, Holstein and Jersey), PopSizeABC revealed a series of population declines, related to historical events such as domestication or modern breed creation. We further highlight that our approach is robust to sequencing errors, provided summary statistics are computed from SNPs with common alleles.

Skeletal variation in Tennessee Walking Horses maps to the LCORL/NCAPG gene region.

Conformation has long been a driving force in horse selection and breed creation as a predictor for performance. The Tennessee Walking Horse (TWH) ranges in size from 1.5 to 1.7 m and is often used as a trail, show, and pleasure horse. To investigate the contribution of genetics to body conformation in the TWH, we collected DNA samples, body measurements, and gait/training information from 282 individuals. We analyzed the 32 body measures with a principal component analysis. Principal component (PC)1 captured 28.5% of the trait variance, while PC2 comprised just 9.5% and PC3 6.4% of trait variance. All 32 measures correlated positively with PC1, indicating that PC1 describes overall body size. We genotyped 109 horses using the EquineSNP70 bead chip and marker association assessed the data using PC1 scores as a phenotype. Mixed-model linear analysis (EMMAX) revealed a well-documented candidate locus on ECA3 (raw P = 3.86 × 10(-9)) near the LCORL gene. A custom genotyping panel enabled fine-mapping of the PC1 body-size trait to the 3'-end of the LCORL gene (P = 7.09 × 10(-10)). This position differs from other reports suggesting single nucleotide polymorphisms (SNPs) upstream of the LCORL coding sequence regulate expression of the gene and, therefore, body size in horses. Fluorescent in situ hybridization analysis defined the position of a highly homologous 5 kb retrogene copy of LCORL (assigned to unplaced contigs of the EquCab 2.0 assembly) at ECA9 q12-q13. This is the first study to identify putative causative SNPs within the LCORL transcript itself, which are associated with skeletal size variation in horses.

Breed differences in everyday behaviour of dogs

The domestication of the dog and the ensuing breed creation has resulted in a plethora of dog breeds that differ not only in morphology but also in terms of behaviour. In addition, a majority of the dogs today are no longer utilized for their working ability, but are mainly kept as companion animals. The main aim of this study was to estimate breed differences in everyday behaviour traits, as well as to study the phenotypic correlations between these traits. Dog owners described their dogs’ everyday behaviour in a questionnaire. The responses to the questions were combined into 18 behavioural subscale scores (BSS). After editing, the material included dog owner responses for 3591 dogs from 20 different breeds. The breeds represent both working and non-working breeds.We can conclude that breed (and grouping into working vs non-working breeds), age and sex had significant effects on many everyday behaviour traits. The working breeds were about 10% more trainable, showed 30% more interest in playing with humans and were 10–60% less fearful. Furthermore, our results showed that fearful dogs were more aggressive, whereas more social dogs were less fearful and less aggressive. We also found that dogs that were more eager to play with humans were also easier to train.

A selective sweep of >8 Mb on chromosome 26 in the Boxer genome.

BackgroundModern dog breeds display traits that are either breed-specific or shared by a few breeds as a result of genetic bottlenecks during the breed creation process and artificial selection for breed standards. Selective sweeps in the genome result from strong selection and can be detected as a reduction or elimination of polymorphism in a given region of the genome.ResultsExtended regions of homozygosity, indicative of selective sweeps, were identified in a genome-wide scan dataset of 25 Boxers from the United Kingdom genotyped at ~20,000 single-nucleotide polymorphisms (SNPs). These regions were further examined in a second dataset of Boxers collected from a different geographical location and genotyped using higher density SNP arrays (~170,000 SNPs). A selective sweep previously associated with canine brachycephaly was detected on chromosome 1. A novel selective sweep of over 8 Mb was observed on chromosome 26 in Boxer and for a shorter region in English and French bulldogs. It was absent in 171 samples from eight other dog breeds and 7 Iberian wolf samples. A region of extended increased heterozygosity on chromosome 9 overlapped with a previously reported copy number variant (CNV) which was polymorphic in multiple dog breeds.ConclusionA selective sweep of more than 8 Mb on chromosome 26 was identified in the Boxer genome. This sweep is likely caused by strong artificial selection for a trait of interest and could have inadvertently led to undesired health implications for this breed. Furthermore, we provide supporting evidence for two previously described regions: a selective sweep on chromosome 1 associated with canine brachycephaly and a CNV on chromosome 9 polymorphic in multiple dog breeds.