In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness.[1] The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously.[2] Outbreeding depression is a risk that sometimes limits the potential for genetic rescue or augmentations.[1] It is considered postzygotic response because outbreeding depression is noted usually in the performance of the progeny.[3]
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.[4]
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.
^ abFrankham, Richard; Ballou, Jonathan D.; Eldridge, Mark D. B.; Lacy, Robert C.; Ralls, Katherine; Dudash, Michele R.; Fenster, Charles B. (2011-04-12). "Predicting the Probability of Outbreeding Depression". Conservation Biology. 25 (3): 465–475. doi:10.1111/j.1523-1739.2011.01662.x. ISSN 0888-8892. PMID 21486369. S2CID 14824257.
^Frankham, R.; Ballou, J.D.; Briscoe, D.A. (2002). Introduction to Conservation Genetics. Cambridge. pp. 382. ISBN 0521702712.
^Waser, Nickolas M.; Price, Mary V.; Shaw, Ruth G. (2000). "Outbreeding Depression Varies Among Cohorts of Ipomopsis Aggregata Planted in Nature". Evolution. 54 (2): 485–91. doi:10.1554/0014-3820(2000)054[0485:odvaco]2.0.co;2. ISSN 0014-3820. PMID 10937225.
^Turcek, FJ (1951). "Effect of introductions on two game populations in Czechoslovakia". Journal of Wildlife Management. 15 (1): 113–114. doi:10.2307/3796784. JSTOR 3796784.
and 27 Related for: Outbreeding depression information
In biology, outbreedingdepression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. The concept...
diversity Heterosis (outbreeding enhancement) Insular dwarfism Island gigantism Minimum viable population Outbreedingdepression Population genetics Rescue...
mutations except when such mutations lead to outbreedingdepression. Consanguinity Heterosis Outbreedingdepression Sharp, C.A. (26 February 1999). "The Downside...
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring...
inbreeding depression, outbreedingdepression emphasizes interactions between loci rather than within them. Inbreeding and outbreedingdepression can occur...
fitness-related traits, but also sometimes leads to negative effects known as outbreedingdepression. However, increased homozygosity increases the probability of fixing...
Androdioecious Caenorhabditis species, C. tropicalis demonstrates outbreedingdepression mediated by Medea like elements, which can result in lethality in...
diverse immunity alleles as a result of outbreedingdepression. A review of the genetics of inbreeding depression in wild animal and plant populations,...
close relatives Manners, the unenforced standards of human conduct Outbreedingdepression, reduced fitness from breeding of unrelated individuals Purebred...
individuals it can result in outbreedingdepression. This is a reduction in fitness, similar to that of inbreeding depression, but arises from a number of...
negatively impacts the fitness of a population, such as through outbreedingdepression and the introduction of unwanted phenotypes which can lead to extinction...
Evidence for the optimal-inbreeding hypothesis is found in outbreedingdepression. Outbreedingdepression involves reduced fitness as a result of random mating...
maintained that local seed is best adapted to local conditions, and that outbreedingdepression will be avoided. Evolutionary biologists suggest that strict adherence...
and/or outbreedingdepression. Dubey explains that genetic extinction can be caused by "hybrid swarms" noting the various degrees of hybrids. Outbreeding depression...
species' ability to evolve to deal with change in the environment Outbreedingdepression Fragmented populations Taxonomic uncertainties, which can lead to...
selfing model Parthenogenesis Inbreeding Outcrossing Inbreeding depressionOutbreedingdepression Sequential hermaphroditism; the organism spends part of its...
(for ex situ conservation), the possibility of inbreeding depression and outbreedingdepression, and taxonomy, ecology, and genetic diversity of the source...
hybrids and their offspring is often reduced (see Haldane's rule and outbreedingdepression). The Indian peafowl is a resident breeder across the Indian subcontinent...
Underdominance Outbreedingdepression Charlesworth, Deborah; Willis, John H. (November 2009). "The genetics of inbreeding depression". Nature Reviews...
this risks the breakdown of coadapted gene complexes, leading to outbreedingdepression. This division of labor increases the chances of survival of the...
populations is essential to avoid harming existing populations and outbreedingdepression. One of the most numerous populations lives in the vicinity of the...
recombined with a different suite of coevolved alleles, leading to outbreedingdepression. Segregation load occurs in the presence of overdominance, i.e....
often lead to anthropogenic hybridization, genetic swamping, and/or outbreedingdepression. On Dall Island, American martens have been introduced and are hybridizing...
from poaching and wildfires. The population is also at risk of outbreedingdepression, as in some parts of Rhodes, mainland European fallow deer are kept...
factors include shorter birth intervals and a lower likelihood of outbreedingdepression or using reliable contraception. There is also the possibility of...
unsuccessful genetic rescue may occur if the addition of new genes causes outbreedingdepression, which decreases their population fitness. Too much gene flow may...