126:(STB) that diminishes yield in wheat crop. The parent species of wheat had little resistance toward STB, but the hybrid species due to transgressive segregation showed a higher resistance toward STB and therefore a higher fitness. You can create a higher resistance to STB by crossing genes together that are efficient. In result, out of 36 crosses there were 31 that showed a higher mean fitness than the control, parent value. These 31 crosses indicate a higher resistance to STB. The crosses used were from other commercial wheat's that were high yielding which is advantageous because there is a lower chance of deleterious (unwanted traits) appearing and therefore an increase in beneficial traits. Transgressive segregation has been found to be useful to create a resistance toward this organism in order to increase the yield of wheat crop.
89:. Epistasis is the event when one allele at a locus prevents an allele at another locus to express its product as if it is masking its effect. Therefore, epistasis can be related to gene over dominance caused by heterozygosity at specific loci. What this means is that the heterozygote (hybrid) when compared to the homozygote (parent) is better adapted and therefore shows more transgressive, extreme phenotypes. All of these causes lead to the appearance of these extreme phenotypes and creates a hybrid species that will deviate away from the parent species niche and eventually create an individual "hybrid" species.
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pollution. Climate change on the other hand can open the gene flow door by breaking climate and environmental barriers that were present before. This convergence between species can give rise to a hybrid species that will have more phenotypic variation when compared to the parent species. This increase in phenotypic variation has the potential for transgressive segregation to occur.
158:. This test looks at whether the hybrid species' performance was different from the control group by looking whether or not the mean of the control group (parent species) differs significantly from mean of the other groups. If there is a difference, that is an indication of transgressive segregation. Another commonly used test is the use of
84:
is another cause for transgressive segregation. Developmental stability refers to the capability of a genotype to go through a constant development of a phenotype in a certain environmental setting. If there is a disturbance due to genetic or environmental factors, the genotype will be more sensitive
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than their parents. As a result, the hybrid species will have some traits that are transgressive (extreme) in nature. Transgressive segregation can allow a hybrid species to populate different environments/niches in which the parent species do not reside, or compete in the existing environment with
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are the two parent groups for the hybrids. Ultimately there were three hybrid sunflower species. When compared to the fitness of the parents, the hybrids showed a higher tolerance in areas which the parent species would not be able to survive i.e. salt marsh, sand dunes, and deserts. Transgressive
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Transgressive segregation creates an opportunity for new hybrid species to arise that are more fit than their ancestors. As seen with the STB in Kenya and
Rieseberg's sunflowers, transgressive segregation can be used to create a species that is more adaptable and resistant in areas where there is
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to assess transgressive segregation. Alleles with QTL that were opposed (either by overdomiance or underdominance) of the parental parent QTL indicate that transgressive segregation occurred. Alleles with QTL that was the same as the predicted parent QTL showed that there was no transgressive
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door would open. This open door will increase the interactions between different species with different genomes can create hybrid species that can potentially show transgressive phenotypes. Human activity can open the gene flow door by pursuing harmful actions such as cutting down forests and
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Other than the genetic factors solely causing transgressive segregation, environmental factors can cause genetic factors to take place. Environmental factors that cause transgressive segregation can be influenced by human activity and
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segregation allowed these hybrids to survive in areas that the parent would not be able to. Therefore, the hybrids were populated in areas where the parent species were not. This is due to hybrid species showing more
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Johansen‐Morris, A. D., and R. G. Latta. "Fitness consequences of hybridization between ecotypes of Avena barbata: hybrid breakdown, hybrid vigor, and transgressive segregation." Evolution 60.8 (2006):
76:
results in new pairs of alleles at two or more loci. These different pairs of alleles can give rise to new phenotypes if gene expression has been changed at these loci. Another cause can be elevated
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Nolte, Arne W.; H David Sheets (2005-06-29). "Shape based assignment tests suggest transgressive phenotypes in natural sculpin hybrids (Teleostei, Scorpaeniformes, Cottidae)". Frontiers in
Zoology
210:
Arama, P. F., J. E. Parlevliet, and C. H. Van
Silfhout. "Trangressive segregation for resistance in wheat to sep toria tritici blotch." African Crop Science Journal8.3 (2000): 213–222.
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Schwarzbach, Andrea E., Lisa A. Donovan, and Loren H. Rieseberg. "Transgressive character expression in a hybrid sunflower species." American
Journal of Botany 88.2 (2001): 270–277.
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populations compared to phenotypes observed in the parental lines. The appearance of these transgressive (extreme) phenotypes can be either positive or negative in terms of
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There are many ways to test if transgressive segregation occurred within a population. One common way to test for transgressive segregation is to use a
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Tanksley, S. D. "QTL analysis of transgressive segregation in an interspecific tomato cross." Genetics 134.2 (1993): 585–596. (p.589)
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to phenotypic changes. Another cause arises from the interaction between two alleles of two different genes, also known as the
80:. When mutation rates are high, it is more probable that a mutation will occur and cause an extreme phenotypic change. Reduced
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There are many causes for transgressive segregation in hybrids. One cause can be due to recombination of additive alleles.
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come together, it will result in a hybrid having a higher fitness than the two parents. The hybrid species will show more
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in the way that the goal for each of these events is to create an organism that is more fit than the last.
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146:(phenotypes) than their parents and also having some genes that are transgressive (extreme) in nature.
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102:. Both human activity and climate change have the capability to force species of a specific
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For example, if a bridge is built that connects two isolated areas to one another, a
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Hegarty, M. J. "Invasion of the hybrids." Molecular
Ecology 21.19 (2012): 4669–4671.
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Rieseberg used sunflowers to show the transgressive segregation of parental traits.
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environmental stress. Transgressive segregation can be seen as
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to interact with other species with different genomes.
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757:Index of evolutionary biology articles
150:Testing for transgressive segregation
118:Examples of transgressive segregation
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122:In Kenya, there is a fungus called
567:Evolutionary developmental biology
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524:Evolution of sexual reproduction
295:Genotype–phenotype distinction
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552:Regulation of gene expression
160:quantitative trait loci (QTL)
46:. If both parents' favorable
722:Endless Forms Most Beautiful
502:Evolution of genetic systems
310:Gene–environment correlation
305:Gene–environment interaction
34:is the formation of extreme
701:Christiane Nüsslein-Volhard
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577:Hedgehog signaling pathway
454:Developmental architecture
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404:Transgressive segregation
32:transgressive segregation
582:Notch signaling pathway
557:Gene regulatory network
440:Dual inheritance theory
124:septoria tritici blotch
82:developmental stability
18:Transgressive phenotype
630:cis-regulatory element
538:Control of development
418:Non-genetic influences
384:evolutionary landscape
59:the parental species.
741:Nature versus nurture
645:Cell surface receptor
562:Evo-devo gene toolkit
461:Developmental biology
399:Polygenic inheritance
325:Quantitative genetics
138:Helianthus petiolaris
781:Biological evolution
650:Transcription factor
365:Genetic assimilation
352:Genetic architecture
746:Morphogenetic field
663:Influential figures
174:genetic engineering
27:Process in genetics
435:Genomic imprinting
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696:Eric F. Wieschaus
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476:Pattern formation
380:Fitness landscape
132:Helianthus annuus
54:and variation in
52:genetic variation
16:(Redirected from
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706:William McGinnis
675:Richard Lewontin
670:C. H. Waddington
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519:Neutral networks
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93:Environmental
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74:Recombination
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30:In genetics,
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613:eyeless gene
509:Evolvability
483:Segmentation
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360:Canalisation
330:Heterochrony
320:Heritability
288:Key concepts
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711:Mike Levine
620:Distal-less
445:Polyphenism
425:Epigenetics
277:development
770:Categories
689:Lac operon
514:Robustness
493:Modularity
488:Metamerism
394:Plasticity
389:Pleiotropy
342:Heterotopy
229:1585–1595.
180:References
167:Importance
36:phenotypes
640:Morphogen
625:Engrailed
608:Pax genes
529:Tinkering
375:Epistasis
370:Dominance
281:phenotype
111:gene flow
776:Genetics
603:Hox gene
591:Elements
572:Homeobox
734:Debates
545:Systems
471:Eyespot
335:Neoteny
68:Genetic
48:alleles
44:fitness
635:Ligand
315:Operon
104:genome
63:Causes
40:hybrid
275:The
135:and
279:of
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268:e
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