Dogs are a domesticated member of the Canine genus. Dogs were domesticated for tasks like hunting and herding, but have become one of our favourite pets due to their unique bond with people.
Population: 900 million+
Scientific name: Canis familiaris
Average weight: 0.5 - ~110 kg
Average Size: 2.5 – 43 in
Habitat: Human settlements (domesticated)
Diet: Omnivores - meat, fruits/vegetables, grains
Phenotypically, dog breeds are very diverse, having been bred for a variety of reasons, including herding livestock (shepherds), hunting (hounds), catching rats (terriers), protection (mastiffs), pulling loads (Huskies), trackers (e.g. bloodhounds), and as companions. This has resulted in a great diversity of size, behaviour and appearance between dog breeds, with the Fédération Cynologique Internationale (FCI) recognising over 340 different breeds. The lifespan of dogs varies between breeds; shorter living breeds (Miniature Bull Terriers, Bloodhounds) have a median lifespan of six-seven years, while the longest living breeds (Toy Poodles, Border Terriers) have median lifespans of 15 years.
The direct ancestor of the dog is extinct - with the grey wolf being the only extant species contributing to its genetic lineage. Dogs were the first animals domesticated, but their origin is disputed. Geographically, Europe, the Middle East, and East Asia are suggested, ranging from 10,000 to 30,000 years ago. There are also competing theories as to how wolves were tamed into dogs. One theory suggests that hunter-gatherers actively tamed wolves by taking in wolf pups to train. Another theory argues that wolves hung around human settlements to eat the carcasses they left, and over time tamer wolves were selected until they became docile enough to be companions.
Dogs are an important group of animals to study for several major reasons, the main one being that they are one of the most widely domesticated animals in the world. Being widely domesticated, dogs have become significantly inbred, which has resulted in pets becoming sick due to a number of inherited diseases. Study of these can not only help in better understanding the health of our pets, but can also help in better understanding similar diseases in humans.
Similarly, domestication of all sorts of organisms - from wheat to dogs and cattle - has allowed us to colonise and thrive in every continent worldwide. However, domestication comes with a genetic cost, and it is important that we understand the processes behind it so that we can understand the changes we have driven in farmyard and crop species, the markers associated with these changes, as well as potential methods to drive better and more intelligent breeding going forwards.
What Earlham Institute is doing.
Dr Luca Penso-Dolfin of the Di Palma Group at EI has been working on dog genomes to better understand how genomes are regulated. The story is often much more complicated than we are used to hearing - and genes are just a part of the picture when it comes to explaining how living things work.
Luca works on microRNA (miRNA). RNA is more commonly known to be the “messenger” that takes information from genes and gets that turned into proteins. However, it also plays other roles, for example in regulation, which is where miRNA comes in. Every cell in the human body has the same DNA and the same genes, so why do eyes look different to teeth, or arms different to livers?
The reason is that genes are regulated differently in different types of cell and in different types of tissue - and much of this is done by miRNA, which effectively can bind to the “messenger” version of RNA and prevent it from being copied into DNA.
This means that, even if a gene is read by a cell, it doesn’t always end up as a protein. In this way, using thousands of different miRNAs, it is possible to fine tune cells so that from the same set of instructions we get many different cell types and tissues.