“In early primates, we can pinpoint a particular ERV integration event into the locus of the pancreatic amylase gene that conferred upon our ancestors the ability to express their amylase genes in the salivary gland. This heritable change provided for tissue-specific expression of the gene and gave us our sweet tooth. Here, the introduction of new gene regulatory DNA sequences close to the transcriptional start site of the amylase gene allowed salivary secretion of amylase. The resulting phenotype must have offered advantages to primates as they developed a diet containing more complex carbohydrates.” Sweet Tooth Book:Viruses: Agents of Evolutionary Invention Source: Viruses: Agents of Evolutionary Invention