Article

Multiple and Ancient Origins of the Domestic Dog

Department of Biology, University of California, Los Angeles, CA 90095-1606, USA.
Science (Impact Factor: 31.48). 07/1997; 276(5319):1687-9. DOI: 10.1126/science.276.5319.1687
Source: PubMed

ABSTRACT Mitochondrial DNA control region sequences were analyzed from 162 wolves at 27 localities worldwide and from 140 domestic
dogs representing 67 breeds. Sequences from both dogs and wolves showed considerable diversity and supported the hypothesis
that wolves were the ancestors of dogs. Most dog sequences belonged to a divergent monophyletic clade sharing no sequences
with wolves. The sequence divergence within this clade suggested that dogs originated more than 100,000 years before the present.
Associations of dog haplotypes with other wolf lineages indicated episodes of admixture between wolves and dogs. Repeated
genetic exchange between dog and wolf populations may have been an important source of variation for artificial selection.

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    • "Different ranges of mtDNA sequencing and molecular clocks used in these studies have provided a wide range of time estimates. Some studies suggested that dogs diverged from wolves about 100 kya [2], whereas others gave a time frame of 5 $ 16 kya [13]. In contrast, recent studies based on the comparison of complete mitochondrial genome variability of modern dogs with that of archaeological materials obtained from extinct wolf-like and dog-like specimens indicated that wolf domestication took place in Europe, about 19 $ 32 kya [18]. "
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    ABSTRACT: To contribute to the complete mitogenome database of the species Canis lupus familiaris and shed more light on its origin, we have sequenced mitochondrial genomes of 120 modern dogs from worldwide populations. Together with all the previously published mitogenome sequences of acceptable quality, we have reconstructed a global phylogenetic tree of 555 C. l. familiaris mitogenomes and standardized haplogroup nomenclature. The phylogenetic tree presented here and available online at http://clf.mtdna.tree.cm.umk.pl/ could be further used by forensic and evolutionary geneticists as well cynologists, for data quality control and unambiguous haplogroup classification. Our in-depth phylogeographic analysis of all C. l. familiaris mitogenomes confirmed that domestic dogs may have originated in East Asia during the Mesolithic and Upper Paleolithic time periods and started to expand to other parts of the world during Neolithic times. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Forensic Science International: Genetics 07/2015; 19:123-129. DOI:10.1016/j.fsigen.2015.06.014 · 3.20 Impact Factor
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    • "The domestic dog (Canis familiaris) has undergone strong morphological selection during domestication , since it descended from the wolf approximately 100,000 years before present (Vilà et al., 1997) or more recently (Klütsch & Savolainen, 2011). While domestication of the dog may have occurred at this time, it is likely that morphological divergence from the wolf occurred only 10,000- 15,000 years ago (Morey, 1994; Vilà et al., 1997), with many of the present morphotypes having an even shorter history. There is evidence that this focus on morphology may have led to unexpected behavioural changes in the dog. "
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    ABSTRACT: Abstract: Neoteny is one way of achieving paedomorphosis, where somatic development is slowed down, but sexual maturity stays on ancestral time-course, resulting in a sexually mature descendant adult that is relatively juvenile with respect to its immediate ancestor. The neoteny thus interferes on many aspects of the biology of the dog, giving rise to many canine breeds differing in physical and behavioral characteristics. Dogs with brachycephalic or dolichocephalic morphology are considered less trainable than mesomorphic breeds. Brachycephalic breeds are considered neotenic because the development of the muzzle is blocked at a very early stage with respect to the final result of the wolf. The aim of the research was to determine whether there is a difference between brachycephalic and dolichocephalic breeds with regard to the motivation to cooperate with the owner. For the research have been used 17 dogs, divided into 2 groups (brachycephalic and dolichocephalic). The two groups of dogs were subjected to two behavioral tests. The first consisted in the recovery of food from a container fitted with a cap, while the second was to recover the food tied to a rope and positioned in a wire mesh cage. Statistical analysis of the data showed a significant difference between the dogs of group 1 and group 2. The dogs in group 2 turn a greater number of glances to the owner in test 1 (Z=2.39; p=0.017) and in test 2 (Z=2.39; p=0.017). Regarding the latency of the gaze, a statistically significant difference is detectable in test 1 where the dogs of group 1 take more time to turn the gaze to the owner (Z=2.26; p=0.024) than those of group 2. Instead a statistically significant difference with respect to the latency of the look in the second test between the two groups of animals (Z=1.88; p=0.060) does not exist. The results of the present study seem to support the hypothesis that brachycephalic dogs show a different behavior compared with dolichocephalic ones; they in fact turn a lower number of glances to the owner and have a longer latency to look him when unable to complete the task. The dog trainability seems, therefore, to be affected by the morphological selection conducted in the past on different breeds. However, given the small number of subjects tested, further researches will need to provide new evidence to support the hypothesis that the brachycephalic dogs are less trainable than dolichocephalic, at least with regard to the execution of specific tasks.
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    • "And phylogenetic analysis of L. sativae populations should provide an understanding of the evolutionary mechanisms underlying the invasion process. Because mitochondrial DNA is variable and has strict maternal heredity and no genetic recombination, it is ideal for examining population genetic structure and tracing the history of organismic variation (Bonatto & Salzano, 1997; Stanley et al., 1996; Vila et al., 1997). In addition, mtDNA provides a good indication of intra-and inter-population variations (Avise, 1994). "
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    ABSTRACT: Abstract In this study, partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene of four Liriomyza sativae (Blanchard) geographic populations in China were sequenced. As for the 784 bp mtDNA-COI gene obtained, six variable sites were found which were all transitions and no base composition was insertions or deletions. Six haplotypes were identified in all the sequences, with five showing polymorphism and one was exclusive. Nucleotide diversity (π) and haplotype diversity (h) ranged from 0.00068 to 0.00300 and 0.53571 to 0.82857, respectively. The phylogenetic trees suggested that six haplotypes constructed two clades. Molecular variance analysis (AMOVA) demonstrated that the genetic variation was not obvious and mainly occurred within geographic populations (94.8%). Most molecular variance within the species was due to the difference of haplotypes among different geographic populations. The genetic characters of the four populations were analyzed by FST value and gene flow (Nm), and the FST and Nm values were 0.174-0.464 and 0.577-2.367, respectively. All results showed that not only the gene flow presented among the four populations but also the genetic differences did. The main reason causing the genetic differences among the four populations was supposed to be related to geographic isolation and host plants aggravated the differences.
    Mitochondrial DNA 12/2014; DOI:10.3109/19401736.2014.987271 · 1.70 Impact Factor
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