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Dog Genetics seminars at the University of Iowa, Iowa City, October 2009
The University of Iowa recently hosted two of the world leaders in Dog Genetics as back to back speakers: Dr. Elaine Ostrander and Dr. Peter Savolainen (see announcements above). It is fair to say that such density of genetic information exchange about dogs by the world leading experts in their respective fields is probably a first. Given the different topics of their respective research, the presentation of data and the discussions after the talks were rather different, Dr. Ostrander’s talk featured the use of Dog Genetics to map complex genetic traits related to leg-length, coat-length and diseases, whereas Dr. Savolainen’s talk focused on the time and place of dog domestication followed by the subsequent dispersal across the world, based on a very large systematic sequencing analysis of hundreds of dog breeds. Below are the summaries of the two talks.
Dogs, like people, have various cancers. Histiocytic sarcoma (HS; previously called malignant histiocytosis) is breed specific, with Bernese Mountain Dogs, Rottweilers, and Retrievers having a high prevalence with a frequency of approximately 25% in the Bernese Mountain Dog breed. Using genetic information on Bernese Mountain Dogs, Dr. Ostrander and colleagues propose an oligogenic transmission mode for this disease and another cancer found with high incidence in Shelties and Scotties. A paper on the complex inheritance of the cancer in these later breeds is now in preparation. Further analysis is needed to localize the genes for HS in the Bernese Mountain Dog, leading to advances in our knowledge of histiocyte diseases and other cancers in dogs and humans and, ultimately, to help in early diagnosis and perhaps even treatment. A simple fact that enhances the ability of this group for these studies is that the mapping density to figure out where mutated genes are located is easier to achieve in dogs compared to humans.
Interesting discussions on dog genome related problems abounded during the dinner and ideas concerning dog genome analysis with respect to bone density related to the human mutation affecting bone density were discussed. It was also agreed that future work is needed to expand the suggestions based on gene mapping by analyzing the functional interactions of those genes in mutant mice and a project is currently discussed to generate mice with short and long legs, assuming that the genes identified in dogs have similar effects in mice. At least the genes related to coat-length, texture and curls are already identified in mice as being related to a similar phenotype.
The subsequent discussion was centered around the problems of how to distinguish spread from southern China from dilution of the southern Chinese dog genes by repeated breeding with wolves (a distinction that can not be made at the moment) and how reverse mutations in the genes should be identified (they can not be, thus generating some noise in the data). During the discussion, data of Dingoes were presented which showed that all Dingoes are derived from a very small and genetically homogeneous pool. The discussion also revolved around the suggested use of early domesticated wolves as food and it was noted that this tradition is not only part of the Chinese culture but is found in various tribes of Africa as well. Fossil evidence showing cooked dog bones is now needed to support this hypothesis. Another point brought up was the claim that African dogs have a somewhat similar haplotype diversity as Chinese dogs. However, this study was only comparing the Dr. Savolainen's et al. previous publication (2002) and does not refute the more extensive recent data just published.
© Dr. Bernd Fritzsch 2009
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