title: A selective sweep of >8 Mb on chromosome 26 in the Boxer genome.
abstract: BACKGROUND
  Modern 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.
  
  
  RESULTS
  Extended 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.
  
  
  CONCLUSIONS
  A 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.
authors: Molecular Genetics Veterinary Service (SVGM), Department of Animal and Food Science, Veterinary School, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain. Javier.quilez@uab.cat
authors: Javier
authors: J
authors: Quilez
authors: Andrea D
authors: AD
authors: Short
authors: Verónica
authors: V
authors: Martínez
authors: Lorna J
authors: LJ
authors: Kennedy
authors: William
authors: W
authors: Ollier
authors: Armand
authors: A
authors: Sanchez
authors: Laura
authors: L
authors: Altet
authors: Olga
authors: O
authors: Francino
mesh_terms: D000818:Animals; D001947:Breeding; D002875:Chromosomes / Q000235:genetics*; D004285:Dogs / Q000235:genetics*; D016678:Genome; D005838:Genotype; D006579:Heterozygote; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D019596:Wolves / Q000235:genetics