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Why do I have dimples but my parents don't?

Published in Genetics and Traits 3 mins read

It's possible to have dimples even if your parents don't because dimples are primarily inherited through an autosomal dominant gene. This means you only need to inherit one copy of the dimple gene from either parent to express the trait. Here’s a breakdown:

Understanding Autosomal Dominant Inheritance

What does it mean?

  • Dominant Gene: This means that if you inherit one gene for dimples, you will likely have dimples, even if your other gene is for no dimples.
  • Inheritance: According to the reference, "the inheritance is autosomal dominant — only one of a pair of genes is required to code for the presentation of dimples and that this gene can be inherited from the mother or father.”

How can you have dimples when your parents don't?

  • Parents as Carriers: While neither of your parents have dimples, it's likely that each parent carries one recessive gene for no dimples and one dominant gene for dimples. They don't express dimples because they do not have two copies of the dominant dimple gene.
  • Chance: There's a possibility that both your parents carried a recessive gene and only passed on the dominant dimple gene to you, thereby manifesting the dimples in you.

Possible Genetic Scenarios

Here’s a simple representation to illustrate the scenario:

Parent 1 Parent 2 Child Genotype Child Phenotype
Dd Dd DD, Dd, dd Dimples if DD or Dd, No dimples if dd
    • D = Dimple Gene (Dominant): The gene responsible for dimples.
    • d = No Dimple Gene (Recessive): The gene responsible for no dimples.
  • Dd = Carrier Parent: A person has one gene for dimples and one for no dimples. They do not have dimples because a single copy of the dominant gene will express the trait.
  • DD = Dimpled Child: A person has two dimple genes, thereby expressing dimples.
  • dd = No Dimpled Child: A person has two no dimples genes, therefore they don't have dimples.

Why it's not always straightforward

  • Variable Expression: Dimples aren't always consistent. Some individuals might have very deep dimples, while others have faint ones.
  • Multiple Genes?: Although generally considered an autosomal dominant trait, it is possible that dimples may be influenced by other genes, making it a little less predictable than a typical single-gene trait.

Summary

  • Dimples are usually inherited as an autosomal dominant trait.
  • You can have dimples if you inherit at least one gene from a carrier parent.
  • Your parents might be carriers of the dimple gene without showing the trait themselves.