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- En biologie de l'évolution, on parle de dépression hybride quand la descendance d'un croisement entre individus de populations différentes a une valeur sélective (ou fitness en anglais) moins importante que les deux parents. La distance génétique entre deux individus est une variable continue qui affecte la valeur sélective de leur descendance avec un optimum.
* Si les parents sont trop proches, la descendance souffre de dépression de consanguinité.
* Si les parents sont issus de deux populations trop éloignées, les individus souffrent de dépression hybride.
* Et enfin, si les parents présentent entre eux une distance génétique optimale, la descendance peut présenter une valeur sélective supérieure à celle de chacun des deux parents ou à la moyenne de leurs valeurs sélectives : c’est la vigueur hybride ou hétérosis. Lorsque deux populations se retrouvent isolées reproductivement, la distance génétique entre les individus des deux groupes augmente au cours du temps jusqu'à ce que la descendance hybride soit affectée de vigueur hybride puis de dépression hybride jusqu'aux cas extrêmes de dépression hybride que sont la stérilité ou l’inviabilité des hybrides (définition « classique » de l’espèce). (fr)
- In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in extinction of the native species or the loss of native adaptations. Outbreeding depression considered post-zygotic response because outbreeding depression is noted usually in the performance of the progeny. Outbreeding depression manifests in two ways:
* Generating intermediate genotypes that are less fit than either parental form. For example, selection in one population might favor a large body size, whereas in another population small body size might be more advantageous, while individuals with intermediate body sizes are comparatively disadvantaged in both populations. As another example, in the Tatra Mountains, the introduction of ibex from the Middle East resulted in hybrids which produced calves at the coldest time of the year.
* Breakdown of biochemical or physiological compatibility. Within isolated breeding populations, alleles are selected in the context of the local genetic background. Because the same alleles may have rather different effects in different genetic backgrounds, this can result in different locally coadapted gene complexes. Outcrossing between individuals with differently adapted gene complexes can result in disruption of this selective advantage, resulting in a loss of fitness. (en)
- 異系交配弱勢（いけいこうはいじゃくせい、英: Outbreeding depression）は、生物学において、遺伝的に遠縁な個体間の交配（異系交配）によって生まれる子供が、両親よりも環境に対する適応度が低く、またはより遺伝的に近縁な個体間の交配によって生まれる子供よりも低いこと。近交弱勢の対義語である。 (ja)
- Depresja outbredowa (ang. Outbreeding depression) − zjawisko gwałtownego obniżenia się kondycji i dostosowania potomstwa dwojga odległych genetycznie rodziców, np. pochodzących z różnych, niewielkich i długo izolowanych populacji. W skrajnych przypadkach zanieczyszczenie puli genowej lokalnej populacji obcym materiałem może doprowadzić do jej wyginięcia. (pl)
- 远交衰退（Outbreeding depression），又稱雜種衰敗、雜種衰退（Hybrid breakdown），是演化生物学中指不同种群之间的后代比同种群的后代有劣势的现象，與杂种优势相反。這是配子後生殖隔離的表現。 (zh)
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- http://www.nwfsc.noaa.gov/publications/techmemos/tm30/lynch.html|title=Inbreeding depression and outbreeding depression (en)
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- 異系交配弱勢（いけいこうはいじゃくせい、英: Outbreeding depression）は、生物学において、遺伝的に遠縁な個体間の交配（異系交配）によって生まれる子供が、両親よりも環境に対する適応度が低く、またはより遺伝的に近縁な個体間の交配によって生まれる子供よりも低いこと。近交弱勢の対義語である。 (ja)
- Depresja outbredowa (ang. Outbreeding depression) − zjawisko gwałtownego obniżenia się kondycji i dostosowania potomstwa dwojga odległych genetycznie rodziców, np. pochodzących z różnych, niewielkich i długo izolowanych populacji. W skrajnych przypadkach zanieczyszczenie puli genowej lokalnej populacji obcym materiałem może doprowadzić do jej wyginięcia. (pl)
- 远交衰退（Outbreeding depression），又稱雜種衰敗、雜種衰退（Hybrid breakdown），是演化生物学中指不同种群之间的后代比同种群的后代有劣势的现象，與杂种优势相反。這是配子後生殖隔離的表現。 (zh)
- In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in ex (en)
- En biologie de l'évolution, on parle de dépression hybride quand la descendance d'un croisement entre individus de populations différentes a une valeur sélective (ou fitness en anglais) moins importante que les deux parents. La distance génétique entre deux individus est une variable continue qui affecte la valeur sélective de leur descendance avec un optimum. (fr)
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- Dépression hybride (fr)
- 異系交配弱勢 (ja)
- Outbreeding depression (en)
- Depresja outbredowa (pl)
- 远交衰退 (zh)
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