Linking livestock genetic diversity with three thousand years of agricultural crises and resilience

ongoing

Over the last 50 years, chicken production has increased fivefold, chicken growth rate has tripled, and milk production per cow has doubled. Yet, many of the biotechnological tools responsible for this accelerated trend are now under threat of becoming obsolete. While the causes are numerous, one significant driver is a dramatic reduction of genetic diversity in livestock populations. Cycles of agricultural productivity growth and decline have occurred throughout European history, spurred by major historical forces such as the spread of empires and continent-wide epidemics. For example, productivity crashed between the 4th-13th centuries, only to rebound during the Agricultural Revolution of the 13-18th centuries. Fluctuating levels of genetic diversity were likely both cause and remedy to these cycles. Genetic diversity acts as a fuel for selection: the lower it is, the more difficult it is to improve traits, and the more likely that epidemics will develop and spread. Given this importance, maintaining diversity amongst livestock is recognised as one of the UN’s Sustainable Development Goals. Despite this, we lack any understanding of how much genetic variability was present, and subsequently lost, before, during, and after either the Green or Agricultural Revolutions, nor do we understand how efficiently it was utilised. PALAEOFARM will assess the long-term sustainability of modern breeding practices by unravelling how genetic variability was leveraged across major agricultural transitions in European history. Using an innovative combination of ancient DNA, archaeozoology, and experimental immunology, I will explore how livestock populations withstood epidemics and selective breeding in a world without antibiotics or quantitative genetic techniques. This will provide a novel perspective on how a multi-billion euro industry, responsible for feeding billions of people, can be sustained in the face of major biotechnological obsolescence.