“Selfing”的意思、由来-开放百科全书

Selfing is widespread – from unicellular organisms to the most complex hermaphroditic plants and animals (especially invertebrates). In unicellular organisms such as Protozoa, selfing can occur when two individuals (or their cell nuclei) interbreed that were produced from a previous mitotic division of the same individual. About 10-15% of flowering plants are predominantly selfing.^[8]

Among hermaphrodite animals there are some that regularly reproduce by self-fertilization. In others, it is a rare event; selfing in such species is more common in adverse environmental conditions, or in the absence of a partner.

Genetic consequences of selfing

Self-fertilization results in the loss of genetic variation within an individual (offspring), because many of the genetic loci that were heterozygous become homozygous. This can result in the expression of harmful recessive alleles, which can have serious consequences for the individual. The effects are most extreme when self-fertilization occurs in organisms that are usually out-crossing^[9]. After several generations, inbreeding depression is likely to purge the deleterious alleles from the population because the individuals carrying them have mostly died or failed to reproduce.

If no other effects interfere, the proportion of heterozygous loci is halved in each successive generation, as shown in the following table.

See also

References

1. ^{{cite web|url=http://en.mimi.hu/biology/selfing.html|title=* Selfing (Biology) - Definition,meaning - Online Encyclopedia|author=|date=|website=en.mimi.hu|accessdate=11 October 2018}}
2. ^{{cite book|author=Mayr E.|year=1963|title=Animal species and evolution (1st ed.)|publisher=Cambridge: Belknap Press of Harvard University Press|isbn= 978-0-674-03750-2}}
3. ^{{cite book|author= Dobzhansky T. |year=1970|title=Genetics of the evolutionary process|publisher= Columbia, New York|isbn=978-0-231-02837-0}}
4. ^{{cite book|author=Stebbins G. L., Jr. |year=1974|title=Flowering plants: evolution above the species level. Belknap Press|isbn=978-0-674-30685-1}}
5. ^{{cite book|author=Mayr E . |year=1982|title=The growth of biological thought: diversity, evolution, and inheritance (1st ed.)|publisher=Cambridge, Mass: Belknap Press|isbn=978-0-674-36445-5}}
6. ^{{cite book |author=Hadžiselimović R.| year=2005|title= Bioantropology - diversity of recent man (in bosnian)|publisher=Institute for genetic engineering and biotechnology|place= Sarajevo|isbn=978-9958-9344-2-1}}
7. ^{{cite book|author=King R. C., Stransfield W. D.|year=1998|title=Dictionary of genetics|publisher=Oxford University Press|place= New York, Oxford|isbn=978-0-19-50944-1-1}}
8. ^{{cite journal |vauthors=Wright SI, Kalisz S, Slotte T |title=Evolutionary consequences of self-fertilization in plants |journal=Proc. Biol. Sci. |volume=280 |issue=1760 |pages=20130133 |date=June 2013 |pmid=23595268 |pmc=3652455 |doi=10.1098/rspb.2013.0133 |url=}}
9. ^{{cite journal |vauthors=Bernstein H, Byerly HC, Hopf FA, Michod RE |title=Genetic damage, mutation, and the evolution of sex |journal=Science |volume=229 |issue=4719 |pages=1277–81 |date=September 1985 |pmid=3898363 |doi= |url=}}