AncestryDNA® Traits
Earlobes
Have you ever noticed there are different types of human earlobes? You may have an attached earlobe, which means it's connected directly to the side of your head, or you may have an unattached earlobe that hangs free. An AncestryDNA® + Traits test can tell you if your DNA suggests you are more likely to have attached earlobes or free earlobes.
Attached Earlobes and Free Earlobes
An earlobe is an earlobe, right? Yes and no. Although the general anatomy of the ear is similar among humans, earlobes can be connected to a person's head in different ways.
If your earlobes form a smooth line where they connect to your head, they are considered attached. If your earlobes form a noticeable notch or angle where they join the head, they are referred to as unattached or free earlobes by some scientists.
Earlobes can have any degree of "attachedness." In some people the notch can be subtle, making it hard to figure out their specific earlobe type.
Genetics of Earlobe Types
For a long time, scientists thought there were only two earlobe types: unattached and attached. They also believed an unattached earlobe was a dominant trait controlled by a single gene.
But neither of these "facts" about human genetics and earlobes turned out to be totally accurate.
The way an earlobe connects to your head is influenced by multiple genetic variations, many of which are unknown. This results in varying angles of attachment.
As for the inheritance pattern, earlobe genetics is still not well understood by scientists. This makes it hard to predict what kind of earlobes children will have based on their biological parents' ears.
Still AncestryDNA® can give you some idea about your earlobe shape by looking at over 3,000 DNA markers across your genome that are associated with the trait.
The Science of Earlobes
Do earlobes serve a purpose? Actually the biological function of earlobes is still unknown. It's possible that earlobes help your ears capture sound and regulate body temperature, but these ideas aren't scientifically proven.
Multiple scientific studies have looked for a connection between earlobe creases, or folds in the earlobe, and coronary artery disease (CAD). The reason is earlobe creases are caused by a similar type of change around small blood vessels as the blood vessel change associated with CAD.
Some studies have shown a correlation between earlobe creases and CAD. But others have shown no correlation, so the connection is inconclusive.
Interesting Facts About Earlobes
The cartilage of the upper ear never stops growing. And what your earlobes look like can change as you age. A few international studies have shown that earlobes seem to get bigger with age; gravity is one potential factor.
While using discs and plates to stretch one’s earlobes may seem to be a more modern trend in Western cities, the practice of stretching one’s earlobes for aesthetic reasons has been practised by societies around the world since ancient times—and is still a common practice in many parts.
For example, youth in the Mursi tribe in Ethiopia stretch their earlobes with large plates to enhance their attractiveness. After piercing their ears, they elongate the earlobes by wearing larger and larger wooden disks over time.
Other cultures, from the Lahu tribe in Thailand to the Aztecs and Mayans in North and Central America have also practised earlobe stretching.
References
Adhikari, Kaustubh, Guillermo Reales, et al. "A Genome-Wide Association Study Identifies Multiple Loci for Variation in Human Ear Morphology." Nature Communications, June 24, 2015. http://doi.org/10.1038/ncomms8500.
"The Ageing Process: What Happens to Our Ears over Time?" BBC News, May 6, 2014. https://www.bbc.com/news/av/health-27277582.
Hawkins, Amanda. "10 Things You Didn't Know About Your Ears." Good Housekeeping, January 12, 2015. http://www.goodhousekeeping.com/health/a26836/ear-facts.
Lai, L.Y.C., and R.J. Walsh. "Observations on Ear Lobe Types." Human Heredity, 1966. https://doi.org/10.1159/000151971.
McClatchey, Caroline. "Ear Stretching: Why Is Lobe 'Gauging' Growing in Popularity?" BBC News, November 21, 2011. http://www.bbc.com/news/magazine-15771237.
McDonald, John H. "Myths of Human Genetics: Attached Earlobe." University of Delaware, December 8, 2011. https://udel.edu/~mcdonald/mythearlobe.html.
Mohanraju, C., and D.P. Mukherjee. "Ear Lobe Attachment in an Andhra Village and Other Parts of India." Human Heredity, 1973. http://doi.org/10.1159/000152588.
Story, Colleen M. "The Heart-Head Connection: Heart Disease and... Ears?" Healthline, January 13, 2018. https://www.healthline.com/health/heart-disease/ear-creases#connection.
Wu, Diane. "Ask a Geneticist: Other Traits." Understanding Genetics. Stanford at the Tech, August 4, 2010. http://genetics.thetech.org/ask/ask372.