New Study on Evolution of Pigs

by 5m Editor
1 March 2010, at 12:28pm

NETHERLANDS - A new project at Wageningen University Research will study the genetic make-up of 12 pig species.

Since the wild boar was domesticated 9000 years ago, its genetic make up has undergone favourable and less favourable changes. In a project financed by the European Research Council (ERC) researchers of Wageningen UR will compare the genetic characteristics of twelve pig species. Among those the Javanese warthog, of which DNA will be extracted from old bones. This makes it possible to track which features have been receptive to change. It will gives us more insight in the evolution of pigs and at the same time creates opportunities to prevent possibly adverse features, like weakened resistance.

Martien A.M. Groenen explains his project into the molecular characterisation of genetic factors in the pig under selection during speciation, domestication and breeding.

In the summary, he writes that ever since Darwin's first description of the theory of evolution, the forces that act during speciation and, to a lesser extent, domestication have attracted much attention. However, details about how speciation events have shaped genomes and vice versa how changes in the genome affect speciation and domestication are still poorly understood. To further address these questions in detail at the molecular level, the pig is of particular interest.

Dr Groenen continued that domestication and selection has resulted in a large number of distinct breeds worldwide with very distinct characteristics. Unique are also the availability of 12 closely related pig species that have diverged over a time span of one to 10 million years. Furthermore, the availability of a high quality genome sequence of the pig by the end of 2009 and the recent advances in next generation sequencing technology makes the SelSweep proposal extremely timely.

Within the SelSweep project, Dr Groenen will explore the genes and genomic regions that have been under strong selection during speciation, early domestication and during subsequent development of specific breeds in the pig.

The results of the project will substantially advance our knowledge of evolutionary biology at the molecular level, he says. Moreover, knowledge about the genes affected by selection opens up new directions for further improvement of this important livestock species. The often rapid adaptation and speciation events have puzzled evolutionary biologists, and structural variation such as copy number variations (CNVs) might be important key aspects playing an important role during these evolutionary events. The direct sequencing of individuals from a variety of populations using next generation sequencing enables an unbiased capture of the full breadth of genetic variation in the porcine genome addressing both single nucleotide polymorphisms (SNPs) as well as CNVs.

The analysis will be done using a previously established porcine HapMap population consisting of domestic breeds from China, Europe and the US, wild boar populations from across the world as well as museum samples representing ancient pig populations.

Also included in the panel are other member of the pig family (Suidae), enabling the identification of the ancestral alleles further strengthening the identification of selective sweeps in the porcine genome.

Mr Groenen says in conclusion that the recent developments in next generation sequencing technology, the availability of a high quality annotated genome sequence by the end of 2009 and the unique collection of genetic material from pigs representing the global gene pool in this species, all contribute to the timeliness and innovation of the SelSweep proposal.