Some traits are controlled by genes that pass from parent to child. Others are acquired through learning. But most are influenced by a combination of genes and environmental factors.
If earlobes hang free, they are detached. If they connect directly to the sides of the head, they are attached. Earlobe attachment is a continuous trait: while most earlobes can be neatly categorized as attached or unattached, some are in-between.
A clear example of the attached earlobe is the actor Clint Eastwood.
Although some sources say that this trait is controlled by a single gene, there are no published studies to support this view. Attachment and the shape of the earlobe are inherited, but many genes are likely to contribute to this trait. As such, their pattern of inheritance is difficult to predict.
In this item, we try to give some genetic clues to help relate the genotype of certain genes to the likelihood of having the earlobe attached to the head or detached.
Gene or region studied