ABOUT GENETIC AILMENTS IN DOGS
When an ailment in a dog occurs, many owners want to blame the breeder. Not all ailments have a genetic component and many factors need to be taken into consideration. How is the dog being maintained? Was a child playing too rough with the dog? Was the dog injured by accident? Did the dog come into contact with an insecticide? A pesticide? Dangerous chemicals? Was the wrong deworming medication given? Was the dog placed on medications or ointments that could cause a sudden health issue? Was the dog exposed to harsh weather related elements? There are so many possibilities to why a dog suddenly and without warning, becomes ill or dies that the list is endless. *The reason we, as humans, targeted the dog genome for decoding is that it's useful for genetic research. The reason it's useful for genetic research is that dogs are neatly divided into breeds, each of which is plagued by specific diseases. And the reason dogs are divided into diseased breeds is that we made them that way. Dogs are the world's longest self-serving, ecologically reckless genetic experiment, perpetrated by the world's first genetically engineering species: us. The human being. *Click here to read more.
Dogs were just a loose category of wolves until around 15,000 years ago, when our ancestors tamed and began to manage them. Humans fed them, bred them, and spread them from continent to continent. While other wolf descendants died out, dogs grew into a new species. Humans invented the dog. Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways. *Click here to read more.
The explosion of dog breeds over the past two centuries represents perhaps one of the greatest genetic experiments ever conducted by humans. Distilled from the genome of the wild wolf are animals that differ by more than 40-fold in size with the ability to herd, guard, hunt, and guide (American Kennel Club 1998). Behavioral variation is surpassed by morphologic variation, with individual breeds represented by dogs of every imaginable size and proportion. Coats alone can be described by color, texture, length, thickness, and curl. Tails can be described as plumed, curled, double curled, gay (upright), sickled (arching), otter (down and flat), whipped, ringed, screwed, or snapped (American Kennel Club 1998). The diversity in skeletal size and proportion of dogs is greater than any mammalian species and even exceeds that of the entire canid family (Wayne 1986a,1986c). Such variation may reflect simple modifications of post-natal development (Wayne 1986a,1986c), but the specific genetic mechanisms are not well known. Mitochondrial DNA studies have not been useful for the reconstruction of breed origins or relationships because the origin of the vast majority of sequence polymorphisms found in dogs preceded the development of modern breeds. Therefore, phylogenetic hierarchies based on DNA sequences reveal the history of mutations that occurred before dogs were domesticated (e.g., Fig. 1C). However, many breeds contain several mitochondrial DNA haplotypes, suggesting that multiple matralines were involved in the founding of a dog breed. To assess the recent evolution and relationships of breeds, microsatellite loci provide a better tool, as their high variability insures allele frequency divergence through drift. Genetic distance trees based on the microsatellite dataset from Parker et al. (2004) revealed several distinct breed clusters. The most divergent grouping presumably contained the most ancient breeds, but none of these nine ancient breeds were of European origin. The ancient breeds included dogs from a wide geographic area including the Arctic, Asia, Africa, and the Middle East. By comparison, the majority of breeds, including European breeds, appeared to stem from a single node without significant phylogenetic structure, which has been termed a "hedge," indicating a recent origin and extensive hybridization between the breeds (Parker et al. 2004; Fig. 2). The focus on breeds belonging to this hedge in past studies probably explains the observed lack of phylogenetic resolution (Zajc et al. 1997; Koskinen and Bredbacka 2000; Irion et al. 2003). CLICK HERE About the UCSC Genome Bioinformatics Site.
