Neznanova, L. | Search bioRxiv

bioRxiv2020

Functional specialization of human salivary glands and origins of proteins intrinsic to human saliva

Salivary proteins are essential for maintaining health in the oral cavity and proximal digestive tract and serve as a diagnostic window into human disease. However, their precise organ origins remain unclear. Through transcriptomic analysis of major adult and fetal salivary glands, and integration with the saliva proteome and transcriptomes of 28+ organs, we linked human saliva proteins to their source, identified salivary gland-specific genes, and uncovered fetal- and adult-specific gene repertoires. Our results also provide new insights into the degree of gene retention during maturation and suggest that functional diversity between adult gland-types is driven by specific dosage combinations of hundreds of transcriptional regulators rather than a few gland-specific factors. Finally, we demonstrate the hitherto unrecognized heterogeneity of the human acinar cell lineage. Our results pave the way for future investigations into glandular biology and pathology, as well as salivas use as a diagnostic fluid.

developmental biology↗

bioRxiv2018

Amylase copy number analysis in several mammalian lineages reveals convergent adaptive bursts shaped by diet

The amylase gene (AMY), which codes for a starch-digesting enzyme in animals, underwent several gene copy number gains in humans1, dogs2, and mice3, presumably along with increased starch consumption during the evolution of these species. Here we present evidence for additional AMY copy number expansions in several mammalian species, most of which also consume starch-rich diets. We also show that these independent AMY copy number gains are often accompanied by a gain in enzymatic activity of amylase in saliva. We used multi-species coalescent modeling to provide further evidence that these recurrent AMY gene copy number expansions were adaptive. Our findings underscore the overall importance of gene copy number amplification as a flexible and fast adaptive mechanism in evolution that can independently occur in different branches of the phylogeny.

evolutionary biology↗