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Topic: Outbreeding depression

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	NOAA/NMFS/NWFSC-TM30: Inbreeding Depression and Outbreeding Depression (Site not responding. Last check: 2007-10-29)
		The converse of inbreeding depression is outbreeding enhancement, which is often referred to as hybrid vigor or heterosis.
		Both outbreeding depression and outbreeding enhancement may be occurring at the same time in a population receiving immigrants.
		Inbreeding depression (I.D.) in laboratory populations of Drosophila.
	www.nwfsc.noaa.gov /publications/techmemos/tm30/lynch.html (4479 words)

	OUTBREEDING DEPRESSION IN HYBRID PINK SALMON
		Although divergence between pink salmon broodlines is large and outbreeding depression might be expected in such unlikely hybrids, the results document the occurrence of outbreeding depression in salmon and signal caution in making management and aquacultural decisions that may create the possibility of outbreeding depression in self-sustaining or cultured populations.
		Outbreeding depression resulting from additive genetic effects would be expected to appear in first generation hybrids (F1), like the depression observed in tolerance to DDT in F1 mosquitoes or the increased susceptibility of F1 coho salmon to the parasite Ceratomyxa shasta.
		Resultant outbreeding depression may not occur until the second or later generations when assortment of alleles at different loci takes place.
	www.nativefishsociety.org /conservation/biblio/wild_vs_hatchery/annotated_bibliography_on_salmon_hatcheries/fitness/outbreeding_depression_in_hybrid.htm (703 words)

	SmallPop
		The decline in the wolves was attributed to inbreeding depression, with the lack of reproducing females attributed to the unwillingness of the wolves to mate with close relatives.
		Outbreeding depression is caused by the interbreeding of different subspecies (= races) leading to diminished fitness of offspring.
		A second example of outbreeding depression also occurred in Czechoslovakia when the large Siberian Roebuck was crossed with the smaller native species.
	faculty.plattsburgh.edu /thomas.wolosz/smallpopulations.htm (2428 words)

	Dispersal and Habitat Selection, Sinervo (Site not responding. Last check: 2007-10-29)
		Outbreeding depression is the tendency to show reduced fitness in progeny that are the product of two very different genetic backgrounds.
		Outbreeding depression is thought to arise from epistatic interactions among loci.
		Outbreeding depression may give rise to a behavioral block to breeding that is similar to species recognition mechanisms.
	bio.research.ucsc.edu /~barrylab/classes/animal_behavior/DISPERSE.HTM (4598 words)

	Inbreeding - Open Encyclopedia (Site not responding. Last check: 2007-10-29)
		Inbreeding often leads to reduced health and fitness (called consanguinity depression); however, livestock breeders often practice inbreeding, then cull unfit offspring, especially when they are trying to establish a new and desirable trait in their stock.
		Within humans, the genetic problems caused by inbreeding are often cited as a factor rationalizing the primitive taboos prohibiting incest.
		Since the late middle ages, it is the urban middle class that has had the widest opportunity for outbreeding.
	open-encyclopedia.com /Inbreeding (308 words)

	Jungle Eyes - Animal Genetics
		Inbreeding depression is where deleterious alleles increase in frequency in the population, and variability decreases.
		It appears that cheetahs have survived the dangerous period of inbreeding depression, and, as a consequence, are now able to inbreed fairly succesfully, without as much danger of deleterious alleles manifesting.
		Outbreeding to increase diversity is not the only answer, though, because when outbreeding occurs the offspring is a hybrid.
	www.jungledomain.org /genetics.htm (2693 words)

	Seed production from the mixed mating system of Chesapeake Bay (USA) eelgrass (Zostera marina; Zosteraceae) -- Rhode ... (Site not responding. Last check: 2007-10-29)
		Montalvo A. Ellstrand 2001 Nonlocal transplant and outcrossing depression in the sub-shrub Lotus scoparius (Fabaceae).
		Ruckelshaus M. 1995 Estimates of outcrossing rates and of inbreeding depression in a population of the marine angiosperm Zostera marina.
		Waser N. 1993a Population structure, optimal outbreeding, and assortative mating in angiosperms.
	intl.amjbot.org /cgi/content/full/91/2/192 (3876 words)

	Cannabis World Online Archive - Fixing Dominant and Recessive Genes — from Breed Your Own Vegetable Varieties (Site not responding. Last check: 2007-10-29)
		To understand the genetic nature of of outbreeding crop varieties we need to understand what happens when plants of outbreeding variety sit in a field open-pollinating (that is crossing however they want or however the bees fly).
		In an outbreeding population, the frequencies of the varius genotypes shift with additional generations until the amount of heterozygosity that is lost by the Aa x Aa crosses is exactly balanced by the heterozygosity that is generated by the AA x aa crosses.
		Many outbreeding or partially outbreeding plants are characterized by two other phenomena that complicate our efforts to create or maintain them: inbreeding depression and self-incompatibility.
	www.cannabisworld.org /vbportal/forums/showthread/t-70584.html (16342 words)

	Laura F. Galloway - Local adaptation & hybrid breakdown publications
		The expression of outbreeding depression often differed between reciprocal hybrids indicating interactions between nuclear and cytoplasmic genes contribute to population differentiation.
		Because plants were grown under greenhouse conditions, the outbreeding depression was likely due to genetic (underdominance or loss of additive-by-additive epistasis) rather than ecological factors.
		Inbreeding and outbreeding depression in natural populations of Chamaecrista fasciculata (Fabaceae): consequences for conservation biology.
	faculty.virginia.edu /galloway/hybridabstracts.html (1408 words)

	STACY, ELIZABETH. (Site not responding. Last check: 2007-10-29)
		For predominantly outcrossed species such as tropical trees, theory predicts that cross-compatibility should be optimized between mates separated by intermediate distances, where both inbreeding and outbreeding depression are avoided.
		The goal of this study was to estimate the degree of cross-compatibility between adult trees separated by a range of distances.
		Apparent outbreeding depression observed at a fairly small scale (~12 km) is more likely due to spatial heterogeneity in the selective environment, than to isolation by distance.
	www.ou.edu /cas/botany-micro/bsa-abst/sympos5/abstracts/6.shtml (247 words)

	Alaska Sea Grant Project R/31-06 (Site not responding. Last check: 2007-10-29)
		To determine if outbreeding depression is detectable in crosses of pink salmon from different regions.
		Outbreeding depression in hybrids between odd- and even-broodyear pink salmon.
		Preliminary tests of outbreeding depression in hybrids between spatially separated pink salmon populations.
	www.uaf.edu /seagrant/research/postaward/R31-06.html (961 words)

	Northwest Alpacas - Are You Afraid of Inbreeding?
		Inbreeding depression is the expression of unfavourable recessive genes in homozygous combinations.
		Outbreeding (also called outcrossing) is the exact opposite to inbreeding.
		Keep in mind that outbreeding is not an insurance against genetic faults and that inbreeding does not always lead to catastrophe.
	www.alpacas.com /AlpacaLibrary/Inbreeding.aspx (1622 words)

	Untitled Document
		Theory predicts that inbreeding depression should be lower in polyploids relative to diploids.
		In a greenhouse study, we found that inbreeding depression was not significant for most seed and germination characters.
		Limited early- and moderate later-life inbreeding depression suggest it is buffered by the higher levels of heterozygosity found in an autotetraploid.
	www.duluth.umn.edu /~jetterso (1665 words)

	Inbreeding = breeding between relatives
		Outbreeding depression caused by loss of well-adapted alleles is also a risk.
		The entire population went extinct as a result of this outbreeding (Greig 1979).
		However, populations tend to recover fitness lost from outbreeding depression more rapidly than from inbreeding depression (Templeton 1983).
	bioweb.wku.edu /faculty/Ameier/popgen2.html (331 words)

	ISAB Hatchery Surplus Review, document ISAB 2001-3
		Outbreeding depression is more likely to occur when interbreeding is between genetically differentiated populations.
		Inbreeding depression is a reduction in the fitness of the progeny of closely related parents, because these progeny are homozygous at more loci for deleterious recessive alleles than the progeny of more distantly related parents.
		The ISAB believes that because of the high risk associated with loss of fitness due to outbreeding depression, deliberate introductions of genetic variation to counteract perceived inbreeding difficulties must be considered very carefully before implementation.
	www.nwcouncil.org /library/isab/isab2001-3.htm (6344 words)

	Faculty Profile Template (Site not responding. Last check: 2007-10-29)
		We are currently concentrating on two areas: 1) the genetic basis of outbreeding depression, and 2) the spatial and temporal genetic structure of natural marine populations.
		Mate choice in the face of both inbreeding and outbreeding depression in the intertidal copepod Tigriopus californicus.
		Heterosis and outbreeding depression in interpopulation crosses spanning a wide range of divergence.
	www.usc.edu /dept/LAS/biosci/faculty/edmands.html (388 words)

	Inbreeding and outbreeding depression in male courtship song characters in Drosophila montana
		Inbreeding depression in these song characters was investigated by comparing the songs of inbred and outbred fly strains.
		Outbreeding depression and the genetic architecture of song characters were investigated with interpopulation crosses and joint scaling tests.
		The possible role of outbreeding depression and epistasis in speciation is discussed.
	www.nature.com /cgi-taf/DynaPage.taf?file=/hdy/journal/v84/n3/abs/6886550a.html (324 words)

	Cross-fertility in two tropical tree species: evidence of inbreeding depression within populations and genetic ...
		of genetic incompatibility and inbreeding and outbreeding depression
		Fischer M. Matthies 1997 Mating structure and inbreeding and outbreeding depression in the rare plant Gentianella germanica (Gentianaceae).
		Schierup M. Christiansen 1996 Inbreeding depression and outbreeding depression in plants.
	www.amjbot.org /cgi/content/full/88/6/1041 (6229 words)

	Re: Preventing loss of genetic diversity
		Outbreeding depression is the biggest negative ramification of hybridization.
		Without more training in population biology, I can't really provide you with a good definition for outbreeding depression, but I suspect there's lots of good, detailed information out there if you want to read more.
		The basic idea is that hybrid animals run into three main problems: (1) coadapted gene complexes are potentially lost in hybridization, (2) local adaptations might render the hybrid offspring unfit (or less fit, to be fair), and (3) (having nothing to do with outbreeding depression) loss of legal protection in some regions.
	www.madsci.org /posts/archives/May2003/1053137111.En.r.html (793 words)

	Nonlocal transplantation and outbreeding depression in the subshrub Lotus scoparius (Fabaceae) -- Montalvo and ...
		Nonlocal transplantation and outbreeding depression in the subshrub Lotus scoparius (Fabaceae)
		of outbreeding depression is operating on survival and reproduction.
		Lynch, M. 1991 The genetic interpretation of inbreeding depression and outbreeding depression.
	www.amjbot.org /cgi/content/full/88/2/258 (7646 words)

	Outbreeding depression in the common frog, Rana temporaria
		Because genetic differentiation is often high between amphibian populations, they could be particularly sensitive to outbreeding depression, e.g.
		The difference in response to outbreeding between populations was accompanied with significant differences in the importance of maternal effects.
		We conclude that care should be taken when translocating frogs between distantly related populations to avoid outbreeding depression.
	www.environmental-expert.com /resulteacharticle4.asp?cid=6063&codi=5372 (208 words)

	Loss of Genetic Diversity Among Managed Populations
		Beyond this loss of genetic variation, mixing two groups can result in outbreeding depression, which is the loss of fitness in offspring that results from the mating of two individuals that are too distantly related (Templeton 1987).
		Inbreeding depression, on the other hand, is the loss of fitness produced by the repeated crossing of related organisms.
		This causes not only the loss of genetic variation among populations, but through outbreeding depression it is also probably negatively affecting the fitness of many native stocks involved.
	biology.usgs.gov /s+t/noframe/e221.htm (1412 words)

	Viewing a thread
		Even if outbreeding depression doesn't exist, the yearly propagation of fish stocked into the Bone Lake brood stock and the re-stocking of fish from the eggs taken there and stocked back into Bone certainly extends the possibility of the perputation of those known small growth fish.
		Outbreeding depression remains one of the hypothesized causes (along with habitat degradation) of failed reproduction in once self-sustaining muskie populations in the midwest (Margenau 1999).
		Outbreeding depression in hybrids of geographically separated populations demonstrates that introgression of nonnative fish can erode fitness, and should be recognized as a potential detriment of both aquaculture and management practices.
	muskie.outdoorsfirst.com /board/forums/thread-view.asp?tid=20499&posts=12 (3873 words)

	Optimal Outcrossing in Erythronium americanum (Site not responding. Last check: 2007-10-29)
		Plants that are able to select the pollen that will fertilize their ovules will likely have more fit offspring than plants that have no control over the paternity of their seeds.
		Inbreeding and outbreeding, the degree of relatedness between two mating individuals, can have a large effect on offspring fitness, both beneficial and deleterious.
		When a plant suffers from both inbreeding and outbreeding depression there should be some optimal outcrossing distance where offspring fitness is maximized.
	www.nsula.edu /scholars/Alumni/Thesis/Thesisabstracts/SItheses/Hobden.html (212 words)

	Conservation Biology (W460)
		Because the PSC considers each population as a potentially a separate evolutionary unit, reintroductions of external stocks or establishment of gene flow between populations must be considered much more carefully under the PSC than the BSC.
		In his essay, Templeton uses the reintroduction of the ibex (Capra ibex) into Czechoslovakia as an example of the potential consequences of outbreeding depression.
		Outbreeding depression is a decline in fitness associated with matings between genetically distinct populations.
	www.humboldt.edu /~tlg2/460/ConsBioExam1Fall2000ver2key.html (999 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		Title : CRB: Inbreeding Depression and Adaptive Genetic Variation in Gila Topminnows Abstract : 9322655 Hedrick In this research, the PI's will examine inbreeding depression over two generations for several components of fitness in different populations of the endangered species, the Gila topminnow.
		As a result, it is important in determining the pattern of genetic variation over populations whether crosses between individuals from different populations are no different than within population crosses, are heterotic, or show outbreeding depression.
		It is therefore of fundamental importance to characterize both the extent of inbreeding depression and adaptive genetic variation in particular endangered species.
	www.cs.utexas.edu /users/yguan/NSFAbstracts/Abstracts/BIO/DEB.BIO.a9322655.txt (365 words)

	Am. J. Bot. -- Sheridan and Karowe 87 (11): 1628
		Inbreeding, outbreeding, and heterosis in the yellow pitcher plant, Sarracenia flava (Sarraceniaceae), in Virginia
		1991 The genetic interpretation of inbreeding depression and outbreeding depression.
		Inbreeding depression and heterosis effects caused by selfing and outcross-ing in Scabiosa columbaria.Evolution 47:1669—1680.
	www.pitcherplant.org /papers/Inbreeding.html (3277 words)

	WDNR -Wisconsin Walleye Management Plan - Issue Statement 26 (Site not responding. Last check: 2007-10-29)
		If there are genetically distinct walleye populations that also have performance differences, theoretically stocking these fish into a different stock of walleye could result in lower fitness of the overall population.
		This phenomena, called outbreeding depression, occurs when stocks that are genetically distant interbreed.
		Outbreeding depression occurs when bass from northern Illinois breed with southern Illinois bass, resulting in lower survival and reproduction of the offspring, when the offspring are stocked back into either northern or southern Illinois waters.
	www.dnr.state.wi.us /org/water/fhp/fish/walleye/issue26.htm (246 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		Inbreeding depression results in increasingly poorer fitness of offspring and is believed to be more widespread than outbreeding depression.
		Examples of outbreeding depression are less well-documented, but such depression may occur in cases where there is extreme local adaptation so that introduction of plants from distant sources could result in disruption of closely-adapted gene complexes.
		Therefore, it would be reasonable to hypothesize that outbreeding depression would be more likely to occur in the case of insect-pollinated species than wind- pollinated species.
	www.stolaf.edu /depts/biology/mnps/papers/Sather2002212.htm (1217 words)

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