DNA methylation and its relationship to Type 1 and Type 2 diabetes. There is a complex interaction between genetics, epigenetics and environment (shown by dashed arrows). Epigenetics (DNA methylation) in combination with genetic and environmental stimuli could either impair pancreatic development and insulin secretion, or lead to insulin resistance at peripheral tissues such as liver, muscle and adipose. A combination of impaired insulin secretion and insulin resistance underlie Type 2 diabetes, whereas impaired pancreatic development and insulin secretion underlie Type 1 diabetes. Genetic inheritance (purple arrows) or abnormal environmental stimuli (blue arrows) alone could either impair pancreatic function, or lead to insulin resistance independently.