Genetic diversity is single-handedly one of the most important evolutionary attributes organisms have achieved through processes of reproduction. Unfortunately, not everything on our planet has as much genetic variation as you may have thought. For example, did you know that nearly every banana in the United States is genetically identical?
It’s true. Most bananas in stores are genetic clones. Same DNA: all copies from one plant that has been spliced, replanted over and over again, resulting in a global market for a single mass-produced lucky banana.
The Cavendish banana is the banana most of us know and love. (Or hate.) What you may not have known until now is that the delicious, yellow, easy-to-peel Cavendish actually signifies the aftermath of a true tragedy.
Back in the 1950s, most bananas were exported from Central America. Anyone who was alive at the time may remember bananas tasting a bit different years ago. There is a reason for that. At the time, the banana industry was busy mass-producing the Gros Michel banana. Like the modern Cavendish, the Gros Michel was also produced through a cloning process. Pretty much every plant in Guatemala and throughout Latin America was one of the same. For the industry, this was fantastic. Bananas became predictable. You always had fruit of the perfect size, appearance, and flavor.
Scientists warned of the dangers of lack of genetic variation. Pests and pathogens would only need to figure out one banana’s weakness and the rest would soon meet the same demise. Banana companies were seeing unprecedented growth and demand with their Gros Michel production. Planting anything else would have meant losing money.
Eventually the inevitable happened. Panama disease arrived: a fungal infection caused by the Fusarium oxysporum f.sp. cubense spore. Panama disease spread like wildfire with no genetic diversity to slow it down. Bright green banana plants turned brown. Once the pathogen arrived, it could lurk in the soil for decades to come. Plantations were devastated.
The banana industry hoped if they could find another banana that resembled the Gros Michel but was resistant to the Panama disease, perhaps it could be planted on the abandoned inflected land restoring the industry to the way it once was. Of course, this was based on the assumption that people would buy any banana as long as it resembled the beloved Gros Michel. Unfortunately, few replacements were in existence. The less-sweet Cavendish was the only similar banana that demonstrated resistance to Panama disease. Without any other viable alternative, the industry ran with it.
The Cavendish is very different from the Gros Michel. Aside from being less sweet, it has a different taste than the Gros Michel. Many people believe this is why banana-flavored candy and other banana-flavored foods do not actually taste like the bananas we eat. The artificial flavor more closely resembles that of the Gros Michel. I can’t help but feel a pang of sadness never knowing I may never know what the much sweeter bananas my grandparents used to eat tasted like.
If you were born after 1950, it is unlikely you have ever purchased any banana other than a Cavendish clone.
The Bad News for Banana Lovers
The bad news is that like the Gros Michel, the Cavendish lacks genetic diversity. A new strain of Fusarium has evolved. It can kill both Gros Michel and Cavendish bananas. This new strain (Tropical Race 4 or TR4) has already spread from Asia to East Africa and seems likely to make its way to Central America. Should this happen, the industry will once again collapse. Fortunately, scientists are trying to genetically engineer the Cavendish to protect us from a repeat of history.