History of livestock
The history of livestock started with the domestication of their wild ancestors: a restricted number of species allowed to be tamed and entered a symbiotic relationship with the human species. In exchange for food, shelter and protection, they provided us with meat, mile, eggs, hides, wool, feathers and draught power, thus contributing considerably to our economic and cultural development.
Depending on the species, domestication took place in different areas and periods with the largest contribution from Southwest Asia 8’000 to 10’000 years ago (Fig. 2). After domestication, livestock spread over all inhabited regions of the earth, accompanying human migrations or conquests and becoming also trade objects. This required an adaptation to different climates and varying styles of husbandry and resulted in an enormous phenotypic diversity.
Loss of genetic diversity
Approximately two hundred years ago, the situation started to change with the rise of the concept of breeds. Animals from the same breed were selected for the same visible characteristics, and crossing of animals with different phenotypes was seriously reduced. This resulted in the formation of many different breeds, mostly genetically isolated from other populations. A few decades ago, selection pressure was increased again with intensive production focusing on a limited range of types and a subsequent loss of genetic diversity. For short-term economic reasons, farmers have abandoned traditional breeds. As a consequence, during the 20th century, at least 28% of farm animal breeds became extinct, rare or endangered. A substantial number of autochthonous breeds are still classified as ‘critical’ in developed countries.
The situation is even more alarming in developing countries, where autochtonous breeds adapted to local environments and diseases are being replaced by industrial breeds. In the most marginal areas, FAnGR are considered to be essential for viable and sustainable land use and, in the developing world, a major pathway out of poverty.
Scientific research into genetic diversity
Historic documentation from the period before the breed formation is scarce. As a consequence, reconstruction of the history of livestock populations depends critically on archaeological, archeozoological and DNA analysis of extant populations. Scientific research into genetic diversity takes advantage of the rapid advances in molecular genetics. Studies of mitochondrial DNA, microsatellite DNA profiling and Y chromosomes have revealed many details on the process of domestication, on the diversity retained by breeds and on relationships between breeds. However, we only see a small part of the genetic information and the advent of new technologies is most timely in order to answer many essential questions.
High-throughput SNP (single-nucleotide polymorphism) genotyping is about to be available for all major farm animal species. The recent development of sequencing techniques and the availability of a huge amount of genomic data calls for new methods of data management and analysis and for new ideas for the extraction of information relevant for proper choices in conservation and valuation of FAnGR. To make sense of this genetic information in practical conditions, integration of geo-environmental and socio-economical data are key elements. The study and management of FAnGR is indeed a major multidisciplinary issue.