“Panmixia”的意思、由来-开放百科全书

A panmictic population is one where all individuals are potential partners. This assumes that there are no mating restrictions, neither genetic nor behavioural, upon the population, and that therefore all recombination is possible. The Wahlund effect assumes that the overall population is panmictic.^[3]

In genetics, random mating^[4] involves the mating of individuals regardless of any physical, genetic, or social preference. In other words, the mating between two organisms is not influenced by any environmental, hereditary, or social interaction. Hence, potential mates have an equal chance of being selected. Random mating is a factor assumed in the Hardy-Weinberg principle and is distinct from lack of natural selection: in viability selection for instance, selection occurs before mating.

Description

In simple terms, panmixia (or panmicticism) is the ability of individuals in a population to interbreed without restrictions; individuals are able to move about freely within their habitat, possibly over a range of hundreds to thousands of miles, and thus breed with other members of the population.

To signify the importance of this, imagine several different finite populations of the same species (for example: a grazing herbivore), isolated from each other by some physical characteristic of the environment (dense forest areas separating grazing lands). As time progresses, natural selection and genetic drift will slowly move each population toward genetic differentiation that would make each population genetically unique (that could eventually lead to speciation events or extirpation).

However, if the separating factor is removed before this happens (e.g. a road is cut through the forest), and the individuals are allowed to move about freely, the individual populations will still be able to interbreed. As the species's populations interbreed over time, they become more genetically uniform, functioning again as a single panmictic population.

In attempting to describe the mathematical properties of structured populations, Sewall Wright proposed a "factor of Panmixia" (P) to include in the equations describing the gene frequencies in a population, and accounting for a population's tendency towards panmixia, while a "factor of Fixation" (F) would account for a population's departure from the Hardy-Weinberg expectation, due to less than panmictic mating. In this formulation, the two quantities are complementary, i.e. P = 1 - F. From this factor of fixation, he later developed the F statistics.

Background information

In a panmictic species, all of the individuals of a single species are potential partners, and the species gives no mating restrictions throughout the population.^[5] Panmixia can also be referred to as random mating, referring to a population that randomly chooses their mate, rather than sorting between the adults of the population.^[6]

Panmixia allows for species to reach genetic diversity through gene flow more efficiently than monandry species.^[7] However, outside population factors, like drought and limited food sources, can affect the way any species will mate.^[8] When scientist examine species mating to understand their mating style, they look at factors like genetic markers, genetic differentiation, and gene pool.^[9]

Panmictic species

A panmictic population of Monostroma latissimum, a marine green algae, shows sympatric speciation in southwest Japanese islands. Although panmictic, the population is diversifying.^[10] Dawson's Burrowing bee, Amegilla dawsoni, may be forced to aggregate in common mating areas due to uneven resource distribution in its harsh desert environment.^[11] Pantala flavescens should be considered as a global panmictic population.^[12]

Related experiments and species

See also

References

1. ^King C and Stanfield W.D. 1997. Dictionary of genetics. Oxford. "Panmixia (panmixis): random mating as contrasted with assortative mating."
2. ^Merriam-Webster Medical Dictionary. "Panmixia: Random mating within a breeding population."
3. ^{{citation|title=Darwinism's Struggle for Survival: Heredity and the Hypothesis of Natural Selection|first1=Jean|last1= Gayon|first2= Matthew|last2= Cobb|publisher=Cambridge University Press|year= 1998|isbn =978-0-521-56250-8|pages=158}}
4. ^{{Cite book | url=https://books.google.com/?id=Guj1AgAAQBAJ&pg=PA51&lpg=PA51&dq=apomorphy+derived+common+ancestor+autapomorphy#v=onepage&q=apomorphy%20derived%20common%20ancestor%20autapomorphy&f=false | title=Bioinformatics for Beginners: Genes, Genomes, Molecular Evolution, Databases and Analytical Tools| isbn=9780124105102| last1=Choudhuri| first1=Supratim| date=2014-05-09}}
5. ^{{Cite web | url=http://schaechter.asmblog.org/schaechter/2009/05/of-terms-in-biology-panmictic.html | title=Of Terms in Biology: Panmictic}}
6. ^{{Cite web | url=https://www.fisheries.noaa.gov/welcome#p | title=Welcome to NOAA | NOAA Fisheries}}
7. ^{{Cite journal |pmid = 16599959|year = 2006|last1 = Beveridge|first1 = M.|title = Panmixia: An example from Dawson's burrowing bee (Amegilla dawsoni) (Hymenoptera: Anthophorini)|journal = Molecular Ecology|volume = 15|issue = 4|pages = 951–7|last2 = Simmons|first2 = L. W.|doi = 10.1111/j.1365-294X.2006.02846.x}}
8. ^{{Cite journal |pmid = 16599959|year = 2006|last1 = Beveridge|first1 = M.|title = Panmixia: An example from Dawson's burrowing bee (Amegilla dawsoni) (Hymenoptera: Anthophorini)|journal = Molecular Ecology|volume = 15|issue = 4|pages = 951–7|last2 = Simmons|first2 = L. W.|doi = 10.1111/j.1365-294X.2006.02846.x}}
9. ^{{Cite journal |pmid = 23620904|year = 2013|last1 = Pujolar|first1 = J. M.|title = Conclusive evidence for panmixia in the American eel|journal = Molecular Ecology|volume = 22|issue = 7|pages = 1761–2}}
10. ^{{cite journal |last1=Bast |first1=Felix |last2=Kubota |first2=Satoshi |last3=Okuda |first3=Kazuo |title=Phylogeographic assessment of panmictic Monostroma species from Kuroshio Coast, Japan, reveals sympatric speciation |journal=Journal of Applied Phycology |date=11 November 2014 |volume=27 |issue=4 |pages=1725–1735 |doi=10.1007/s10811-014-0452-x}}
11. ^{{Cite journal|title = Panmixia: an example from Dawson's burrowing bee (Amegilla dawsoni) (Hymenoptera: Anthophorini) |journal = Molecular Ecology|date = 2006-04-01|issn = 1365-294X|pages = 951–957|volume = 15|issue = 4|doi = 10.1111/j.1365-294X.2006.02846.x|language = en|first = Maxine|last = Beveridge|first2 = Leigh W.|last2 = Simmons|pmid=16599959}}
12. ^{{Cite journal|authors= Daniel Troast, Frank Suhling, Hiroshi Jinguji, Göran Sahlén, Jessica Ware|title=A Global Population Genetic Study of Pantala flavescens|journal=PLOS One|year=2016 |volume=11 |issue=3|pages=e0148949|doi=10.1371/journal.pone.0148949 |pmid=26934181|pmc=4775058|bibcode=2016PLoSO..1148949T}}
13. ^{{Cite journal |doi = 10.1186/1471-2164-15-403|pmid = 24884429|pmc = 4229938|title = In absence of local adaptation, plasticity and spatially varying selection rule: A view from genomic reaction norms in a panmictic species (Anguilla rostrata)|journal = BMC Genomics|volume = 15|pages = 403|year = 2014|last1 = Côté|first1 = Caroline L.|last2 = Castonguay|first2 = Martin|last3 = Kalujnaia|first3 = Mcwilliam|last4 = Cramb|first4 = Gordon|last5 = Bernatchez|first5 = Louis}}
14. ^{{Cite journal |doi = 10.1186/s12862-016-0720-2|pmid = 27455997|pmc = 4960869|title = Unravelling population genetic structure with mitochondrial DNA in a notional panmictic coastal crab species: Sample size makes the difference|journal = BMC Evolutionary Biology|volume = 16|pages = 150|year = 2016|last1 = Fratini|first1 = Sara|last2 = Ragionieri|first2 = Lapo|last3 = Deli|first3 = Temim|last4 = Harrer|first4 = Alexandra|last5 = Marino|first5 = Ilaria A. M.|last6 = Cannicci|first6 = Stefano|last7 = Zane|first7 = Lorenzo|last8 = Schubart|first8 = Christoph D.}}