Eukaryotes Genomes - CANIS FAMILIARIS

Canis familiaris is part of the genus Canidae, the family of carnivorous mammals commonly known as canines. It includes dogs, wolves, foxes, coyotes and jackals. Canis familiaris was probably domesticated from the wolf 10-12,000 years ago.

Suppression, selection, and mixing within the wolf gene pool have yielded hundreds of breeds of domestic dog. Dogs are unique among mammalian species in the extent of variation they show in morphological traits such as height, weight, mass, shape, and behaviour, yet within each breed, key traits are inherited within extremely narrow limits. The Chihuahua is less than 30cm at the shoulder; the Irish wolfhound close to a meter. The Pomeranian weighs between 1-3kg; the St. Bernard may weigh 60kg. Dog breeds exist which have been purpose bred for guarding, hunting, herding, driving, pulling, etc. No other mammalian species presents natural variation on a scale to rival these, yet individuals from nearly any breed can be mated to yield fertile offspring.

Given the aggressive breeding programs needed to reproducibly generate animals of distinctive size, shape and behaviour, it is not surprising that purebred dog fanciers have also produced closed breeding populations, characterised by over 400 inherited disorders. Genetic diseases are predicted to occur with high frequency in populations with closed gene pools and in which breeding of close relatives is used to propagate desired traits. Breeds established from a small number of founders and expanded rapidly to meet breeders' and consumers' demands suffer the most. Autosomal recessive and complex traits present the biggest problem as the status of asymptotic carriers may not be suspected until several litters have been produced. This includes diseases such as cancer, heart disease, deafness, blindness, motor neuron disease, skin disorders, and a host of autoimmune disorders, each of which has been difficult to study in humans.

A major goal of the dog genome project is to develop a map that will be useful to the entire scientific community for the purpose of mapping genes causing inherited disease in dogs. It is widely recognised that in many pedigree dog lines diseases run in families. Much of the revolution in human molecular medicine has been catalyzed by the development of the human genetic map, which has allowed genes responsible for human genetic disease to be isolated. The map being produced by the dog genome project will catalyze a similar explosion in veterinary medicine and will allow more effective breeding practices to eliminate many genetic diseases from breeds currently afflicted.

Even with this large number of different breeds, the common characteristics of a dog are fit muscles, high endurance, proportional balanced height and weight, and ability to use all five senses to the maximum, including a sixth sense which scientists call an electromagnetic sense that allows dogs to sense tremors and vibrations.

Dogs thrive in small social groups or packs which from their cynomorphic (dog) viewpoint may include humans. Dog packs are characterised by companionate hierarchy , in which each individual has a rank, and in which there is intense loyalty within the group. Dogs thrive in human society because their relationships with humans mimic their natural social patterns. The dog is always aware of its rank relative to other individuals in the group, and an assertive dog may consider itself the alpha animal, while considering its human owner to be subordinate.

References:

http://www.genome.gov/Pages/Research/Sequencing/SeqProposals/CanineSEQedited.pdf
http://mendel.berkeley.edu/dog.html
http://www.havahart.com/dogs/history_of_dogs.htm
http://en.wikipedia.org/wiki/Dog#Ancestry_and_history_of_domestication