Neolithic Revolution

The Neolithic Revolution and Genetics
The prehistoric shift of many hunters-and-gathers to farmers is defined in history as the Neolithic Revolution that took place around 10,000 years ago. During this time period major environmental and dietary changes occurred due to the settlement of a permeant location and change in food source. These changes lead to changes affecting population genetics and nutrigenomics as disease susceptibility increased and dietary intake changed. Nutritional Genomics is the study of the relationship between the human genome, nutrition and health. It is divided into two branches, nutrigenomics, and nutrigenetics. Nutrigenomics studies the effects of food and nutrition on gene expressions and how certain foods affect
Hunter-and-gather diet consist of a variety of meat and different plants whereas farmers are confined to the crops they grow and the few animals they domesticate. Increasing population size due to farming and herding would have suggested that the overall health of the population is increasing (Armelagos et al. 1996), on the contrary, evidence suggest an increase in infectious and nutritional diseases such as lice, malaria, staphylococci, salmonella, measles, pertussis, smallpox, TB, influenza and many others. Many of these diseases emerge from domesticated animals that act as carriers. Additionally, the warmer climate during the Neolithic period provided many bacteria and pathogens a desirable environment to grow. Agriculture’s role in the transmission of diseases includes changing the transmission ecology of existing pathogens, increasing the success of pre-existing pathogen vectors, and increased carriers of diseases.(Pearce-Duvet, 2006) The increases in susceptibility to diseases can also be accredited to the lack of hygiene, poor knowledge of prevention and
Resistance is determined by balancing selection, which is the selective process of allele’s frequencies remaining in a gene pool longer than expected due to genetic drift. The sickle cell mutation provides resistance to malaria in Sub-Saharan Africa and appears in high allele frequencies in these population. However, areas that are least likely exposed to malaria sickle cell trait would be devastating because it does not provide any benefits. The population who had earlier exposure to diseases lead to genes that gained resistance against secondary exposure. Hence, resistance selection of pathogens varies within populations. Agriculture allowed for the population to grow eventually leading to the great civilizations in fertile valleys of the Nile, Tigris-Euphrates, Yellow and Indus Rivers. These large populations allowed for infectious diseases to be easily transmitted and difficult to control. Cook used the MHC gene also known as the HLA region to measure genetic diversity of gene variants. The HLA region shows the greatest diversity within the human genome. This indicates it goes through constant selection in environments that have a high frequency of infectious diseases. However as the human genome changes to prevent against these pathogens, these pathogens at the same time are undergoing natural selection as well. A mutant form of the pathogen