Editing Four-leaf clover (section)

==Cause==
[[File:Four Leaf Clover (7258825680).jpg|thumb|upright|A 4-leaf clover amongst others with three leaflets]]
It is debated whether the fourth leaflet is caused genetically or environmentally. Its relative rarity (1 in ~5,000 clovers<ref name="auto"/>) suggests a possible [[recessive gene]] appearing at a low frequency. Alternatively, four-leaf clovers could be caused by [[somatic mutation]] or a developmental error of environmental causes. They could also be caused by the interaction of several genes that happen to segregate in the individual plant. It is possible all four explanations could apply to individual cases. This means that multiple four-leaf clovers could be found in the same cloverplant, and a cloverplant that already has a clover with an abnormal number of leaflets has a higher chance of growing or having another abnormal clover than a cloverplant that doesn't have any.<ref>{{cite book |title= Compendium of Symbolic and Ritual Plants in Europe: Herbs |volume= 2 |author= Marcel Cleene, Marie Claire Lejeune |publisher= Man & Culture |year= 2002}}</ref>

Researchers from the University of Georgia have reported finding the gene that turns ordinary three-leaf clovers into the coveted four-leaf types. Masked by the three-leaf gene and strongly influenced by environmental conditions, molecular markers now make it possible to detect the presence of the gene for four-leaves and for breeders to work with it. The results of the study, which also located two other leaf traits in the white-clover genome, were reported in the July/August 2010 edition of ''[[Crop Science (journal)|Crop Science]]'', published by the Crop Science Society of America.<ref>Tashiro, R.M., et al. ''[https://www.crops.org/publications/cs/abstracts/50/4/1260 Leaf Trait Coloration in White Clover and Molecular Mapping of the Red Midrib and Leaflet Number Traits]''. Crop Science, 7 June 2010.</ref>

The other leaf traits, the red fleck mark and red midrib, a herringbone pattern that streaks down the center of each leaflet in a bold red color, were mapped to nearby locations, resolving a century-old question as to whether these leaf traits were controlled by one gene or two separate genes. White clover has many genes that affect leaflet color and shape, and the three in the study were very rare. These traits can be quite attractive, particularly if combined with others, and can turn clover into an ornamental plant for use in flower beds.<ref>[http://parrottlab.uga.edu/parrottlab/Clover/index.htm] {{Webarchive|url=https://web.archive.org/web/20201111220434/https://parrottlab.uga.edu/parrottlab/Clover/index.htm|date=11 November 2020}} The Georgia White Clover Ornamental Collection.</ref>

[[File:Five-leaf clover.jpg|thumb|A 5-leaf clover from the species Trifolium repens. Notice the [[Red|reddish]] or slightly rusty coloration of the leaf.]]

According to an experiment made in 2019 by the, at that moment, 17-year old Minori Mori, from [[Tsukuba]], Japan, four-leaf clovers seem to be more likely to appear in well-[[Fertilizer|fertilized]] soil. [[Phosphate|Phosphates]] (a common ingredient in fertilizers) have been proved to play a role in the frequency of development of four-leaf clovers in cloverplants. A plant hormone called [[auxin]], which plays an important role in [[plant development]], has also been shown to increase the probability of mutations in clovers, especially the development of clovers with more than four leaflets. One study reportedly achieved clovers with five to eight leaflets (within a ten day span) using double of the regular dose of phosphate fertilizer and seeds from a cultivar that produces clovers with four leaflets more frequently. Auxin was also given to the plants with their water, with a concentration of 0.7%.<ref>{{cite web |title=Need a little luck? Here’s how to grow your own |url=https://www.snexplores.org/blog/eureka-lab/isef-2019-how-to-grow-a-four-leaf-clover |website=[[Science News Explores]] |publisher=Sid Perkins |date=15 May 2019}}</ref>

There are reports of farms in the US which specialize in four-leaf clovers, producing as many as 10,000 a day (to be sealed in plastic as "lucky charms") by introducing a [[genetic engineering|genetically engineered]] ingredient to the plants to encourage the aberration (there are, however, widely available [[cultivar]]s that regularly produce leaves with multiple leaflets&nbsp;– see below).<ref>Mabey, Richard, Ibid, p. 225</ref>