Hundreds of genes influence whether ear lobes dangle or are attached at the base.
Ear-lobe attachment was once proffered as a textbook example of a trait controlled by a single gene. A new study provides the most detailed evidence so far refuting it.
Sijia Wang at the Chinese Academy of Sciences in Shanghai, Seth Weinberg at the University of Pittsburgh in Pennsylvania and their colleagues used genetic-sequencing data and ear-lobe observations from 74,660 people with European, Latin American or Chinese ancestry. The team identified 49 genome regions related to the trait, and then sequenced genes expressed in the ears of mouse and human fetuses, including genes affected by most of the regions identified in adults.
Better understanding the genes regulating ear lobes could help to treat developmental abnormalities of the ear, jaw and mouth.