Recently, I came across a YouTube video by Rabbit Hole, a creator that focuses on anomalies in our daily lives. One of her recent videos details the specific methods to hunt four leaf clovers, as well as the rarity and interesting demographics of the clover population. The intricacies of nature are all around us, and this made me interested in clovers, which are such an abundant species all around us.
The four leaf clover, or shamrock, symbolizes luck in Irish tradition. When we talk about clovers, we are alluding to the white clover species, or Trifolium repens. Originally native to Eurasia, it is the most widely cultivated clover species in the world, found on every warm continent. Safe to say, if you find a clover, it’s most likely a white clover. Clovers provide vast benefits wherever they are grown by producing abundant crops, serving as food to livestock, and fixing nitrogen levels in soil. Clovers are also easy to maintain, as they use symbiotic bacteria in its root nodules—tiny swellings on the roots—reducing the need for synthetic fertilizers, and they can adapt in many types of environments.
There are around three hundred other species of clover, all united under the name Trifolium, meaning “three leaves,” which shows the inherent scarcity of four leaf clovers as they aren’t even accounted for in the name of the species. While there are other species of plants that may seem like Trifolium repens and have four leaflets, such as European waterclover, Marsilea quadrifolia, or four-leaf sorrel, Oxalis tetraphylla, when categorizing four leaf clovers, the only real ones are white clovers. About one in ten thousand clovers have four leaflets, but how can we scientifically characterize this? How are four leaf clovers influenced by genetic mutation and the clover genetic makeup?
Although the specific cause of the four leaflet mutation in white clover has still not been pinpointed, plant scientists believe that it is caused by a recessive gene that appears at low frequency.
Identifying the cause of the four leaflet mutation has been difficult because of the white clover’s unique reproductive habits. The standard white clover is a tetraploid, which means that it contains four complete copies of the genome in each cell. Specifically, Trifolium repens is an allotetraploid. Within the four copies of the genome, it contains the genomes of two different clovers T. occidentale and T. pallescens that hybridized thousands of years ago. In the wild, clovers are almost incapable of breeding with themselves and need to outbreed with other plants, making it tricky to pinpoint a specific place where the chromosome originates. Combined with an increased number of chromosomes from its tetraploidal nature, it is increasingly harder for scientists to pinpoint the specific four-leaf gene.
Recently, clover breeders at the University of Georgia have reported finding a gene that turns ordinary three-leaf clovers into four-leaf types by using molecular markers to detect the presence of the gene in a region of the genome that they believe houses the gene.
An alternative explanation for the mutation could be that it arises from somatic mutations, which occur in any body cell except for germ cells (sperm and egg cells). They can be caused by environmental factors or errors in DNA replication.
But most scientists agree that the four-leaf phenotype is a result of a combination of factors. Wayne Parrott, a plant geneticist at the University of Georgia says, “If the genetics are there, the environment determines whether the four leaves show up or not.” Clovers have a higher chance of being four-leafed in warmer months, but that is only possible if the gene is expressed or is present enough. Additionally, the amount of leaflets isn’t limited to just four. This was proven by Yoshiharu Watanabe in 2023, when he found a clover that had an astounding sixty-three leaflets.
With the existence of collaboration between genes and the environment to express a phenotype, the situation becomes even more complicated. The possibilities with the genetics of clovers is seemingly endless, and researchers still have not successfully pinpointed a specific gene that causes this mutation, especially due to the effects of the environment meddling with results.
Whether you are a clover enthusiast or someone who vaguely believes in the lucky superstition surrounding the four-leaf clover, it is still grounded by the same genetic concepts and possibilities that all organisms have.
If you ever want to find a four (or more) leaf clover on your own, here are some tips. Zone out, don’t focus on small patches, instead keep your head on a swivel and scan big patches of clovers to look for patterns. You are much more capable at finding disruptions in the pattern than you think. Specifically, focus on the inner pattern of Trifolium repens, the white shape in the center of the triangle. Notice how the center will be triangular most of the time, but four leaf clovers look more like diamonds. You should also search in high stress areas, places with a lot of foot traffic that encourage more and more mutation to happen. Lastly, if you find one in one spot, keep looking! You are bound to find more due to the sheer amount of clovers that exist everywhere.
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