Genetics of Earlobes

Similar to the human eyes, nose, and lips, the earlobes also have unique features. Although the human ears appear similar, minor structural differences make each ear different from the other.

The primary form of the gene that determines the shape of the earlobe is known as an allele. An allele is a gene that is found at a specific position on a chromosome. It has been established that all genes in our body have two copies, one from each parent.

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Types of earlobes

An earlobe is made up of connective tissues combined with a mixture of areola tissues and fat cells. Earlobes have a good blood supply, which helps in keeping them warm and maintaining balance. There are two primary types of earlobes found in humans, which include free earlobes and attached earlobes.

Free earlobes

Free earlobes are the most common form of ear lobes in humans. This type of earlobe is often large and hangs below the point of attachment to the head. This happens due to the influence of a dominant allele. If the parents' genes express the dominant allele, the child will be born with free earlobes.

In most cases, the allele is regnant to the free lobes compared to attached lobes. The free earlobe parents can also give birth to an attached earlobe child, depending on the allele gene's reaction. If parents with free earlobes give birth to a baby with attached earlobes, both of them had both a copy of the dominant and recessive allele.

Attached earlobes

Attached earlobes are not rare but are also not commonly found. Earlobes of such type are small in size and are attached directly to the side of the head. This kind of lobe's structural formation is due to the absence of the dominant allele in the chromosomes. The recessive allele is expressed to form an attached earlobe. Parents with attached earlobes will not necessarily give birth only to children with attached earlobes.

Traits are the major factors that result from chromosome pairs, which determine one’s overall physical appearance. When alleles combine, some exert a ‘stronger’ influence as compared to others. The stronger allele is responsible for the dominant traits.

If the dominant allele fails to show its presence, the recessive allele will be expressed. These are known as recessive traits.

Although the traits vary, the size of the earlobes for both the traits remains the same. An average man’s ear measures about 6 centimeters (cm), while for a woman, it is about 5 cm, in which the earlobe size measures about 2 cm.

Genetic diseases and earlobes

Genetic conditions play an important role in the birth of a human being. People born with abnormal growth of organs are considered to be affected by the traits before their birth.

Birth disorders may be minor or severe and may occur at any stage during pregnancy. Most disorders affect the baby while in the womb, before the formation of the organs; however, not all genetic defects are caused by the parents' transfer of genes. In many cases, the baby may be born with genetic disorders that the parent’s gene does not contain. Some defects are considered to be harmless, while some may require prolonged medical treatment.

The major conditions that cause irregular or abnormal growth and can subsequently affect the appearance of the earlobes include Down's syndrome, Turner syndrome, and Beckwith-Wiedemann syndrome (BWS).

Down’s syndrome

Down’s syndrome is a condition caused by the presence of an extra chromosome. Generally, a person has 46 chromosomes; however, people with Down’s syndrome have 47 chromosomes. The extra chromosome may influence the growth and development of the body.

People with this syndrome tend to have large ears, a small neck, and a flat face. Down’s syndrome cannot be cured, but the affected person can grow healthily without any trouble.

Turner syndrome

Only females are affected by Turner syndrome, which is a rare condition in which there is a lack of one or part of the second X chromosome. It is assumed that this chromosomal abnormality occurs due to an error in the parent’s reproductive cell. A person with this syndrome will have abnormal ears, eyes, skeletal structure, and even kidney abnormalities.

BWS

BWS is described as the modification that occurs in the genes of chromosome 11. BWS is an excessive growth disorder indicated by large body parts, enlarged tongue, earlobe creases, etc.

The earlobe crease is a wrinkle in the earlobe, which occurs due to the trait that was passed genetically by the family. The wrinkle is created when the flow of blood is decreased in the ear. Currently, there is no method of treatment identified to cure ear creases.

Further Reading

Last Updated: Apr 30, 2021

Afsaneh Khetrapal

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Afsaneh Khetrapal

Afsaneh graduated from Warwick University with a First class honours degree in Biomedical science. During her time here her love for neuroscience and scientific journalism only grew and have now steered her into a career with the journal, Scientific Reports under Springer Nature. Of course, she isn’t always immersed in all things science and literary; her free time involves a lot of oil painting and beach-side walks too.

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Comments

  1. Sky Vasquez Sky Vasquez United States says:

    What if you have one attached earlob and the otjer un-attached? Does this mean anything genetically?

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