The dog was the first domesticated animal but it remains uncertain when the domestication process began and whether it occurred just once or multiple times across the Northern Hemisphere. To ascertain the value of modern genetic data to elucidate the origins of dog domestication, we analyzed 49,024 autosomal SNPs in 1,375 dogs (representing 35 breeds) and 19 wolves. After combining our data with previously published data, we contrasted the genetic signatures of 121 breeds with a worldwide archeological assessment of the earliest dog remains. Correlating the earliest archeological dogs with the geographic locations of 14 so-called "ancient" breeds (defined by their genetic differentiation) resulted in a counterintuitive pattern. First, none of the ancient breeds derive from regions where the oldest archeological remains have been found. Second, three of the ancient breeds (Basenjis, Dingoes, and New Guinea Singing Dogs) come from regions outside the natural range of Canis lupus (the dog's wild ancestor) and where dogs were introduced more than 10,000 y after domestication. These results demonstrate that the unifying characteristic among all genetically distinct so-called ancient breeds is a lack of recent admixture with other breeds likely facilitated by geographic and cultural isolation. Furthermore, these genetically distinct ancient breeds only appear so because of their relative isolation, suggesting that studies of modern breeds have yet to shed light on dog origins. We conclude by assessing the limitations of past studies and how next-generation sequencing of modern and ancient individuals may unravel the history of dog domestication.genomics | phylogeography D arwin speculated about the origins of several domestic animals and suggested that, given the vast morphological variation across numerous breeds, dogs must have had more than one wild ancestor (1). Recent genetic studies, however, support the notion that dogs are descended exclusively from the gray wolf (Canis lupus) (2).Beyond questions regarding wild ancestry, geneticists and generations of archeologists have investigated not only how and why dogs were domesticated, but also when, where, and how many times it may have occurred. Unique among all domestic animals, the first unambiguous domestic dogs precede the appearance of settled agriculture in the archeological record by several thousand years. Identifying the earliest dogs is difficult, however, because key morphological characters established by zooarcheologists to differentiate domestic animals from their wild wolf ancestors (e.g., size and position of teeth, dental pathologies, and size and proportion of cranial and postcranial elements) were not yet fixed during the initial phases of the domestication process. Furthermore, the range of natural variation among these characters in ancient wolf populations and the time it took for these traits to appear in dogs are unknown. Free-ranging wolves attracted to the refuse generated by human camps most likely followed a commensal pathway to domestica...

In cooperation with breed clubs and practising veterinarians throughout Norway, the elbow joints of rottweilers, Bernese mountain dogs and Newfoundlands were screened for osteophyte formation/arthrosis, indicating primary elbow lesions. The changes were graded 0 to 3 and the results subjected to statistical analysis regarding frequencies, frequencies relative to sex, relative risks, differences between offspring groups and heritability. The number of dogs examined were: rottweilers, 1423, Bernese mountain dogs, 414 and Newfoundlands, 209. The frequency of elbow arthrosis varied from 30 to 50 per cent, males being more often and more severely affected than females. The relative risk of developing arthrosis among offspring of affected animals compared to offspring of non‐affected animals, was 1–6. Heritability varied from 10‐4 per cent to 47‐8 per cent, depending on the method used. Based on these results, it is concluded that elbow screening programmes should be carried out in breeds disposed to elbow lesions. Breeding animals should be selected on the basis of the elbow status of parents and other relatives, if possible.

Hereditary multifocal renal cystadenocarcinoma and nodular dermatofibrosis (RCND) is a naturally occurring canine kidney cancer syndrome that was originally described in German Shepherd dogs. The disease is characterized by bilateral, multifocal tumors in the kidneys, uterine leiomyomas and nodules in the skin consisting of dense collagen fibers. We previously mapped RCND to canine chromosome 5 (CFA5) with a highly significant LOD score of 16.7 (theta=0.016). We have since narrowed the RCND interval following selection and RH mapping of canine genes from the 1.3 x canine genome sequence. These sequences also allowed for the isolation of gene-associated BACs and the characterization of new microsatellite markers. Ordering of newly defined markers and genes with regard to recombinants localizes RCND to a small chromosomal region that overlaps the human Birt-Hogg-Dubé locus, suggesting the same gene may be responsible for both the dog and the phenotypically similar human disease. We herein describe a disease-associated mutation in exon 7 of canine BHD that leads to the mutation of a highly conserved amino acid of the encoded protein. The absence of recombinants between the disease locus and the mutation in US and Norwegian dogs separated by several generations is consistent with this mutation being the disease-causing mutation. Strong evidence is provided that the RCND mutation may have a homozygous lethal effect (P<0.01).

Our results support that age has a significant effect on several hematologic and serum biochemical values in puppies, warranting age-specific RI.

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