Allogamy

Allogamy or cross-fertilization is the fertilization of an ovum from one individual with the spermatozoa of another.[1][2] By contrast, autogamy is the term used for self-fertilization.[1] In humans, the fertilization event is an instance of allogamy. Self-fertilization occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual.[3] This is common in plants (see Sexual reproduction in plants) and certain protozoans.[4][5]

In plants, allogamy is used specifically to mean the use of pollen from one plant to fertilize the flower of another plant and usually synonymous with the term "cross-fertilization" or "cross-pollination" (outcrossing).[4] The latter term can be used more specifically to mean pollen exchange between different plant strains or even different plant species (where the term cross-hybridization can be used) rather than simply between different individuals.[6]

Allogamy is achieved through the use of external pollinating factors. The process of allogamy involves two types of external pollinating agents, known as abiotic agents and biotic agents. The abiotic agents are water and wind. The biotic agents are insects and animals, which include bees, butterflies, snails, and birds. Wind pollination is referred to as anemophily, and water pollination is referred to as hydrophilly. Insect pollination is referred to as entomophily, bird pollination is referred to as omithophily, and snail pollination is referred to as malacophily.[7]

Allogamy can lead to homozygosity. After reaching homozygosity, the species develop homozygous balance and fail to exhibit inbreeding depression. Mechanisms that promote self-pollination include homogamy, bisexuality, cleistogamy, the position of anthers, and chasmogamy.[8]

Allogamy promotes genetic diversity and reduces the risk of inbreeding depression. The persistent prevalence of allogamy throughout different species implies that this strategy provides selective advantages concerning adaptation to changing environments and sustaining fitness.[9]

Parasites having complex life cycles can pass through alternate stages of allogamous and autogamous reproduction, and the description of a hitherto unknown allogamous stage can be a significant finding with implications for human disease.[10]

  1. ^ a b Martin, Elizabeth; Hine, Robert (2015-09-17), Martin, Elizabeth; Hine, Robert (eds.), "fertilization", A Dictionary of Biology, Oxford University Press, doi:10.1093/acref/9780198714378.001.0001, ISBN 978-0-19-871437-8, retrieved 2022-03-16
  2. ^ "cross-fertilization". www.britannica.com. Encyclopaedia Britannica. Retrieved 2022-03-16.
  3. ^ Jarne, Philippe; Finot, Luc; Delay, Bernard; Thaler, Louis (1991). "Self-Fertilization Versus Cross-Fertilization in the Hermaphroditic Freshwater Snail Bulinus globosus". Evolution. 45 (5): 1136–1146. doi:10.2307/2409721. ISSN 0014-3820. JSTOR 2409721. PMID 28564176.
  4. ^ a b Lloyd, David G.; Schoen, Daniel J. (1992). "Self- and Cross-Fertilization in Plants. I. Functional Dimensions". International Journal of Plant Sciences. 153 (3): 358–369. doi:10.1086/297040. ISSN 1058-5893. JSTOR 2995676. S2CID 85344103.
  5. ^ Mikami, Kazuyuki (2000), Tarín, Juan J.; Cano, Antonio (eds.), "Fertilization in Protozoa", Fertilization in Protozoa and Metazoan Animals: Cellular and Molecular Aspects, Berlin, Heidelberg: Springer, pp. 1–25, doi:10.1007/978-3-642-58301-8_1, ISBN 978-3-642-58301-8, retrieved 2022-03-16
  6. ^ Arriola, Paul E.; Ellstrand, Norman C. (1997). "Fitness of Interspecific Hybrids in the Genus Sorghum: Persistence of Crop Genes in Wild Populations". Ecological Applications. 7 (2): 512–518. doi:10.2307/2269516. ISSN 1051-0761. JSTOR 2269516.
  7. ^ Panawala, Lakna (2017). "Difference Between Allogamy and Xenogamy".
  8. ^ "Crop Improvement: Mode of Pollination".
  9. ^ Ariane, Mendes (2024). "Mating System Analysis and Genetic Diversity of Parkia Multijuga Benth. One Native Tree Species of the Amazon". Forests. 15 (1): 172. doi:10.3390/f15010172. ProQuest 2918759358.
  10. ^ Baird, Wm. Vance; Riopel, James L. (1986). "Life History Studies of Conopholis americana (Orobanchaceae)". The American Midland Naturalist. 116 (1): 140–151. doi:10.2307/2425946. ISSN 0003-0031. JSTOR 2425946.