Do Humans Really Share 50% of Their DNA with Bananas?

You've likely encountered the surprising 'fact' that humans share 50% of their DNA with bananas. [2, 5] This intriguing claim, often used as a fun piece of trivia, is technically misleading. ^[2] The reality is both more complex and more fascinating, revealing a great deal about how life on Earth is connected.

Genes vs. DNA

The crucial distinction lies in the difference between DNA and genes. ^[1] Our DNA (Deoxyribonucleic acid) is the entire instruction manual for building and maintaining an organism. Genes, on the other hand, are specific chapters in that manual that code for proteins, which perform a vast array of tasks in the body. [3, 5] Genes actually make up only about 2% of our DNA. [1, 5] The other 98% consists of regulatory elements that control genes and non-coding sections, some of which is referred to as 'junk DNA'. ^[5]

So, when you hear the 50% figure, it's actually referring to the similarity in genes, not the entire DNA sequence. ^[1] We share about 50-60% of our genes with bananas. ^[2] However, because genes are such a small fraction of our total DNA, this equates to only about a 1% similarity in our overall DNA. ^[1]

Why the Genetic Similarity?

The reason for this shared genetic heritage is a common ancestor. ^[3] All living things on Earth, from humans to bananas, evolved from a single-celled organism that lived billions of years ago. ^[3] Many of the genes we share with bananas are so-called 'housekeeping' genes. ^[3] These genes are responsible for fundamental cellular functions like cell division, DNA replication, and converting food into energy—processes essential for nearly all life. [1, 3] These ancient genes have been conserved through billions of years of evolution. ^[3]

The Origin of the Claim

The statistic appears to have originated from a project by the National Human Genome Research Institute in 2013 for a Smithsonian Museum of Natural History exhibit. [2, 4] In that project, they found that the human genome is about '41 percent similar' to that of a banana. [2, 4] This figure was an average of the similarity between the proteins of the two organisms. ^[4]

While the idea that we are half-banana is a fun oversimplification, the scientific truth is a powerful illustration of the shared evolutionary history of all life on our planet. [3, 5]