Pigs and wild boars eats almost everithing, despite of their excelent smell. They can find a truffe, which posseses a taste and an aroma highly appreciated in international cuisine. Besides, they eat a rotten fruit, meat or vegetable, a dreadful flavor for humans. But why?
An international scientist team has secuenced the genome of this species, using wild specimens from Spain, and domestic breeds born in China and in different european countries. It can throw light to this issue and open up new research paths in biomedicine, as the pig is a model used in the investigations of human diseases.
Over the last ten years 150 scientist from 40 institutions on 12 countries took part in the investigation, a huge combined effort. Miguel Pérez Enciso, a researcher from the Autonomous University of Barcelona (UAB) and the Agrogenomic Investigation Centre (GRAG) was involved.
Pérez Enciso believe that this paper has been "a milestone in animal genomics and its implications on the scientific, technological and biomedical soon will be felt." The results of this research, led by the universits of Wageningen (holand), Edimburg (Britain) and Illinois (USA), are published in Nature.
The key to unlocking riddles for the pigs food preferences is on his genes. Those related to the sense of taste and smell had had a very different evolution than humans ones.
Nowadays, pigs can't recognise bitter flavour. As a consecuence, they don't care about eating foods that no other mammals can, like rotten vegetables. "These results, therefore, explain why the pig really eats everything", according to the UAB.
Scientists had compared the pig genetic profile with other mammals, like the rat, dog, horse, cow and to the human one also. They estimate that pigs genes shares 84% with humans.
As genetic shows, pigs have many things in common with humans: they are travelers, they can adapt to a new enviroment and survive on it; they can invade a territory and usually cause damages to their own habitat.
But, when pigs had shown up? Wild boar specie named 'sus scrofa' appeared in the asian south east 4 million years ago. According to their tireless traveller nature, pigs had expanded across Asia, Europe and the north of Africa.
Later, about ten million years ago, humans domesticated wild boar and pigs came up. This process occurred at the same time in many places in Europe an Asia so, when Marco Polo visited China, he discovered chinese pigs and exported them to Italy.
Research also revealed that asian and european wild boars separated their genetic structure one million years ago, when the adaptations to the enviroment caused differences gently.
As for the implications in biomedicine, the scientists detail that pork contains several mutations whose effect in humans has been linked to increased risk of diseases such as alzheimer's, diabetes and dyslexia. This would be very helpful to find out wich are the illness mechanisms and develope new treatment.
The genetic changes occurring in endangered species might increase their extinction probabilities. Low population sizes leads to reduced genetic diversity and increased inbreeding. A low of genetic diversity means a reduced ability to adapt to environmental changes. Inbreeding is often associated to reduced reproduction and survival. Genetic factors might thus play an important role in species extinction -and therefore in their conservation.
Molecular genetic markers are often used to assess the genetic status of endangered species and populations. This information is then used to elaborate conservation plans designed to maximize genetic diversity and minimize inbreeding.