Dominance, overdominance or epistasis based models are commonly used explanations.
Tanja Gärtner, Matthias Steinfath, Sandra Andorf, Jan Lisec, Rhonda C Meyer, ThomasAltmann, Lothar Willmitzer, Joachim Selbig 2009, 'Improved heterosis prediction by combining information on DNA- and metabolic markers.',PLoS ONEhttp://europepmc.org/articles/PMC2666157?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Dominance and overdominance were the major genetic foundations of heterosis in rice.
Xueli Zhang, Congwei Sun, Zheng Zhang, Zhijun Dai, Yuan Chen, Xiong Yuan, ZhemingYuan, Wenbang Tang, Lanzhi Li, Zhongli Hu 2017, 'Genetic dissection of main and epistatic effects of QTL based on augmented tripletest cross design', PLOS ONE10.1371/journal.pone.0189054. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
They showed reduced growth and survival suggesting recessive load or overdominance.
Otto Seppälä, Laura Langeloh 2016, 'Estimating Genetic and Maternal Effects Determining Variation in Immune Function ofa Mixed-Mating Snail', PLOS ONE10.1371/journal.pone.0161584. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Plant height was inherited mainly in terms of negative overdominance (34.2% combinations).
В. Г. Михайлов, О. З. Щербина, О. О. Тимошенко, С. О. Ткачик 2017, 'Inheritance and breeding value of the “plant height” trait in the first (F1)and second (F2) soybean generations', Plant Varieties Studying and Protectionhttp://journal.sops.gov.ua/article/view/97237. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Examples of overdominance are usually explained by deleterious effects in homozygotes.
Roman T. Kellenberger, Kelsey J. R. P. Byers, Rita M. De Brito Francisco, YannickM. Staedler, Amy M. LaFountain, Jürg Schönenberger, Florian P. Schiestl, Philipp M.Schlüter 2019, 'Emergence of a floral colour polymorphism by pollinator-mediated overdominance', Nature Communicationshttp://link.springer.com/article/10.1038/s41467-018-07936-x. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Double overdominance now maintains these four alleles across treated and nontreated areas.
Pierrick Labbé, Claire Berticat, Arnaud Berthomieu, Sandra Unal, Clothilde Bernard,Mylène Weill, Thomas Lenormand 2007, 'Forty years of erratic insecticide resistance evolution in the mosquito Culex pipiens.',PLoS Geneticshttp://europepmc.org/articles/PMC2077897?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
It also induces associative overdominance at neutral sites but rarely causes increased neutral genetic diversity in equilibrium populations.
Diego Bersabé, Armando Caballero, Andrés Pérez-Figueroa, Aurora García-Dorado 2016, 'On the Consequences of Purging and Linkage on Fitness and Genetic Diversity', G3: Genes, Genomes, Geneticshttp://g3journal.org/lookup/doi/10.1534/g3.115.023184. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The traits were controlled mainly by an overdominance model, suggesting the advantage of delaying selection to later generations.
Particularly elusive have been cases of heterozygosity for single gene mutations causing heterosis under a genetic model known as overdominance.
Ke Jiang, Katie L Liberatore, Soon Ju Park, John P Alvarez, Zachary B Lippman 2013, 'Tomato yield heterosis is triggered by a dosage sensitivity of the florigen pathwaythat fine-tunes shoot architecture.', PLoS Geneticshttp://europepmc.org/articles/PMC3873276?pdf=render. Retrieved from PLOS CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)