Hybridization, transgressive segregation, genetic covariation, and adaptive radiation

Bell, Michael A.; Travis, Matthew P.

doi:10.1016/j.tree.2005.04.021

Cited by 117 publications

(99 citation statements)

References 14 publications

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“…Specifically, the morphometric variation in this species is characteristic of that predicted by transgressive segregation (29,(34)(35)(36)(37). The predicted pattern of hybridization-induced transgressive segregation is that the hybrid lineage possesses a range of variability outside of that of the parental taxa (34).…”

Section: Discussionmentioning

confidence: 83%

Natural hybridization generates mammalian lineage with species characteristics

Larsen

Marchán-Rivadeneira

Baker

2010

Proc. Natl. Acad. Sci. U.S.A.

136

144

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Most diploid species arise from single-species ancestors. Hybrid origins of new species are uncommon (except among polyploids) and are documented infrequently in animals. Examples of natural hybridization leading to speciation in mammals are exceedingly rare. Here, we show a Caribbean species of bat (Artibeus schwartzi) has a nuclear genome derived from two nonsister but congeneric species (A. jamaicensis and A. planirostris) and a mitochondrial genome that is from a third extinct or uncharacterized congener. Artibeus schwartzi is self-sustaining, morphologically distinct, and exists in near geographic isolation of its known parent species. Island effects (i.e., area, reduced habitat variability, and geographic isolation) likely have restricted gene flow from parental species into the Caribbean populations of this hybrid lineage, thus contributing to local adaptation and isolation of this newly produced taxon. We hypothesize differential rates of the development of reproductive isolation within the genus and estimate that 2.5 million years was an insufficient amount of time for the development of postzygotic isolation among the three species that hybridized to produce A. schwartzi. Reticulated evolution thus has resulted in a genomic combination from three evolutionary lineages and a transgressive phenotype that is distinct from all other known species of Artibeus. The data herein further demonstrate the phenomenon of speciation by hybridization in mammals is possible in nature.Artibeus | Chiroptera | hybrid speciation | reticulate evolution | transgressive segregation D espite empirical studies documenting the establishment of animal hybrid lineages (1-8), the evolutionary importance of speciation by natural hybridization in animals is unknown and often is considered minor because the offspring of such crosses typically are less fit than either parental species (9, 10). Nearly all reported cases of homoploid speciation events (hybrid speciation without change in chromosome number) (11) in animals are among species of insects or fish (12), and there are only a handful of suspected cases in mammals (13-17). Thus hybrid speciation appears to be especially rare in mammals, a consequence of either unfavorable conditions for hybrid speciation to occur (i.e., ecological, physiological, hybrid zone structure) or a lack of empirically based research (18,19). Here, we describe a zone of admixture on a series of Caribbean islands within which three species of Neotropical bats have hybridized resulting in a novel lineage with species-level distinction. Our genetic and morphometric analyses have identified a unique hybrid zone among species of fruit-eating bats, leading us to the hypothesis that natural hybridization has generated a distinct lineage that exists in these insular populations. Our data also indicate that this phenotypic and genotypic combination is geographically isolated from extant parental species on the southern Lesser Antillean island of Saint Vincent.Two species of fruit-eating bats, Artibeus jamaicensis...

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Section: Discussionmentioning

confidence: 83%

Natural hybridization generates mammalian lineage with species characteristics

Larsen

Marchán-Rivadeneira

Baker

2010

Proc. Natl. Acad. Sci. U.S.A.

136

144

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“…By contrast, the results in this study for cpDNA were consistent with strong gene flow via pollen, and the secondary contact between the two lineages of A. alba populations led to the homogenization of genetic structure primarily by the transport of only pollen from the Balkan refugium after isolation during the LGM. Such an exchange of genetic information between refugia would produce hybrid individuals with the creation of new genotypic combinations resulting in transgressive phenotypes well outside the paternal norms that are widely considered to be better adapted to new, local environmental conditions [46][47][48]. Moreover, the results of this study did not support the prior presumption concerning the distinctiveness of the Sudeten and Carpathian A. alba populations based on previous studies using isoenzyme markers [22,23] and provenance experiments [49][50][51].…”

Section: Discussionmentioning

confidence: 99%

Spatial Pattern of the Mitochondrial and Chloroplast Genetic Variation in Poland as a Result of the Migration of Abies alba Mill. from Different Glacial Refugia

Litkowiec

Lewandowski

Rączka

2016

Forests

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Currently, the information on the gene pool of silver fir (Abies alba Mill.) at the northeastern edge of its distribution in Poland is scarce and insufficient. Using the advantage provided by markers with different modes of inheritance, a hypothesis that gene flow via both seeds and pollen contributed to the genetic structure across the entire analyzed region was investigated. The geographic distribution of maternally inherited mitochondrial DNA (mtDNA, nad5-4) and paternally inherited chloroplast DNA (cpDNA, psbC) variation was studied in 81 Polish populations and three reference populations from Ukraine and Romania. The spatial pattern of mtDNA haplotypes (dispersed via seeds) indicated that the Apennine Peninsula was the only maternal glacial refugium for the entire territory of Poland and also the Ukraine no 1 population, whereas the other two populations-Ukraine no 2 and Romania-had the haplotype representing the Balkan origin. By contrast, the cpDNA haplotypes (dispersed via pollen) from all studied Polish and reference populations showed that A. alba colonized the current natural range from two genetically distinct glacial refugia located on the Apennine and Balkan peninsulas. The occurrence of cpDNA haplotypes varied among the studied populations. Additionally, statistical analyses were used to infer the genetic structure of examined populations. Two distinct groups of A. alba populations were identified showing the postglacial geographic distribution of haplotypes of both mtDNA and cpDNA. A. alba is an important ecological and economic component of forest ecosystems in Europe. An understanding of the Holocene history of this species is relevant for planning sustainable forest management, and acquired data can contribute to strategies of conservation and restoration.

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“…the bounded-hybrid superiority model [93]). For instance, hybridization can result in transgressive segregation [94,95], the creation of extreme phenotypes outside the phenotypic limits observed in both parental species (Box 1, Fig. 1).…”

Section: Consequences Of Increasing Genetic Exchange For Biodiversitymentioning

confidence: 99%

Broken barriers: Human‐induced changes to gene flow and introgression in animals

et al. 2011

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We identify two processes by which humans increase genetic exchange among groups of individuals: by affecting the distribution of groups and dispersal patterns across a landscape, and by affecting interbreeding among sympatric or parapatric groups. Each of these processes might then have two different effects on biodiversity: changes in the number of taxa through merging or splitting of groups, and the extinction/extirpation of taxa through effects on fitness. We review the various ways in which humans are affecting genetic exchange, and highlight the difficulties in predicting the impacts on biodiversity. Gene flow and hybridization are crucially important evolutionary forces influencing biodiversity. Humans alter natural patterns of genetic exchange in myriad ways, and these anthropogenic effects are likely to influence the genetic integrity of populations and species. We argue that taking a gene-centric view towards conservation will help resolve issues pertaining to conservation and management. Editor's suggested further reading in BioEssays A systemic view of biodiversity and its conservation: Processes, interrelationships, and human culture Abstract.

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Hybridization, transgressive segregation, genetic covariation, and adaptive radiation

Cited by 117 publications

References 14 publications

Natural hybridization generates mammalian lineage with species characteristics

Natural hybridization generates mammalian lineage with species characteristics

Spatial Pattern of the Mitochondrial and Chloroplast Genetic Variation in Poland as a Result of the Migration of Abies alba Mill. from Different Glacial Refugia

Broken barriers: Human‐induced changes to gene flow and introgression in animals

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