The separation of the earlobe from the skin of the head is a polygenic trait that is largely influenced by the genetic factor and the origin of the individual.
Ear lobe type
The human pinna consists of a piece of cartilage covered with skin and attached to the skull by ligaments, muscles and fibrous tissue. This cartilage does not extend to the earlobe, which is mainly made up of areolar and adipose tissue.
There is a large nonpathologic variation among humans in the shape and size of the pinna, and this variation has been reported to be influenced by age, sex, and ethnicity.
The earlobe can be found either separate from the skin of the head or attached to the skin of the head. Earlobe attachment is a continuous feature: although most earlobes can be neatly classified as attached or unattached, they have features in between.
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Genes analyzed
ADAMTS9-AS2
EDAR
ITGA8
Bibliography
Shaffer JR, Li J, Lee MK, Roosenboom J, Orlova E, Adhikari K, et al. Multiethnic GWAS Reveals Polygenic Architecture of Earlobe Attachment. Am J Hum Genet, 2017; 101(6):913–24.
Adhikari K, Reales G, Smith AJP, Konka E, Palmen J, Quinto-Sanchez M, et al. A genome-wide association study identifies multiple loci for variation in human ear morphology. Nat Commun, 2015; 6(1):7500.
