Enhanced Edar signalling has pleiotropic effects on craniofacial and cutaneous glands

• Published in: PloS one Vol. 4; no. 10; p. e7591
• Main Authors: Chang, Shie Hong, Jobling, Stephanie, Brennan, Keith, Headon, Denis J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26-10-2009; Public Library of Science (PLoS)
• Subjects: Acne; Alleles; Animals; Appendages; Breast cancer; Edar Receptor - metabolism; Evaporation; Evolution & development; Evolutionary Biology/Developmental Evolution; Evolutionary Biology/Evolutionary and Comparative Genetics; Evolutionary Biology/Evolutionary Ecology; Evolutionary Biology/Human Evolution; Female; Fibers; Follicles; Gene frequency; Genetic engineering; Glands; Hair; Hair - physiology; Heterozygote; High frequencies; Human populations; Infections; Life sciences; Lipids; Lubrication; Male; Mammary glands; Mammary Glands, Animal - metabolism; Mice; Mice, Transgenic; Models, Biological; Morphology; Mutation; Phenotype; Population; Population genetics; Populations; Positive selection; Rodents; Salivary Glands - metabolism; Sebaceous Glands - metabolism; Secretions; Signal Transduction; Signaling; Skin; Skin - metabolism; Sweat; Thickening; Transgenic mice
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0007591

The skin carries a number of appendages, including hair follicles and a range of glands, which develop under the influence of EDAR signalling. A gain of function allele of EDAR is found at high frequency in human populations of East Asia, with genetic evidence suggesting recent positive selection at this locus. The derived EDAR allele, estimated to have reached fixation more than 10,000 years ago, causes thickening of hair fibres, but the full spectrum of phenotypic changes induced by this allele is unknown. We have examined the changes in glandular structure caused by elevation of Edar signalling in a transgenic mouse model. We find that sebaceous and Meibomian glands are enlarged and that salivary and mammary glands are more elaborately branched with increased Edar activity, while the morphology of eccrine sweat and tracheal submucosal glands appears to be unaffected. Similar changes to gland sizes and structures may occur in human populations carrying the derived East Asian EDAR allele. As this allele attained high frequency in an environment that was notably cold and dry, increased glandular secretions could represent a trait that was positively selected to achieve increased lubrication and reduced evaporation from exposed facial structures and upper airways.