scholarly journals Evolution of multiple postzygotic barriers between species of the Mimulus tilingii complex

Evolution ◽  
2020 ◽  
Author(s):  
Gabrielle D. Sandstedt ◽  
Carrie A. Wu ◽  
Andrea L. Sweigart
Keyword(s):  
Postzygotic Barriers

Behavioral Isolation and Incipient Speciation in Birds

2018 ◽  
Vol 49 (1) ◽  
pp. 1-24 ◽  
Author(s):  
J. Albert C. Uy ◽  
Darren E. Irwin ◽  
Michael S. Webster
Keyword(s):  
Behavioral Changes ◽  
Reproductive Barriers ◽  
Incipient Speciation ◽  
Mating Preferences ◽  
Early Stages ◽  
Behavioral Isolation ◽  
Intermediate Phenotypes ◽  
Postzygotic Barriers ◽  
Avian Diversification ◽  
And Migration

Behavioral changes, such as those involved in mating, foraging, and migration, can generate reproductive barriers between populations. Birds, in particular, are known for their great diversity in these behaviors, and so behavioral isolation is often proposed to be the major driver of speciation. Here, we review empirical evidence to evaluate the importance of behavioral isolation in the early stages of avian speciation. Experimentally measured mating preferences indicate that changes in mating behavior can result in premating barriers, with their strength depending on the extent of divergence in mating signals. Differences in migratory and foraging behavior also can play important roles in generating reproductive barriers in the early stages of speciation. However, because premating behavioral isolation is imperfect, extrinsic postzygotic barriers, in the form of selection against hybrids having intermediate phenotypes, also play an important role in avian diversification, especially in completing the speciation process.

scholarly journals Postzygotic barriers isolate sympatric species ofCyrtandra(Gesneriaceae) in Hawaiian montane forest understories

2015 ◽  
Vol 102 (11) ◽  
pp. 1870-1882 ◽  
Author(s):  
Melissa A. Johnson ◽  
Donald K. Price ◽  
Jonathan P. Price ◽  
Elizabeth A. Stacy
Keyword(s):  
Sympatric Species ◽  
Montane Forest ◽  
Postzygotic Barriers

scholarly journals Intra- and Inter-Specific Crosses among Centaurea aspera L. (Asteraceae) Polyploid Relatives—Influences on Distribution and Polyploid Establishment

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1142 ◽  
Author(s):  
Alfonso Garmendia ◽  
María Ferriol ◽  
David Benavent ◽  
P. Pablo Ferrer-Gallego ◽  
Hugo Merle
Keyword(s):  
Mating System ◽  
Ploidy Level ◽  
Competitive Advantages ◽  
Polyploid Complex ◽  
Specific Hybridization ◽  
Evolutionary Advantage ◽  
Postzygotic Barriers ◽  
Exclusion Effect ◽  
Sterile Hybrids

How polyploids become established is a long-debated question, especially for autopolyploids that seem to have no evolutionary advantage over their progenitors. The Centaurea aspera polyploid complex includes diploid C. aspera and two related tetraploids C. seridis and C. gentilii. Our purpose was to study the mating system among these three taxa and to analyze its influence on polyploid establishment. The distribution and ploidy level of the Moroccan populations, and forced intra- and inter-specific crosses were assessed. Allotetraploid C. seridis produced more cypselae per capitulum in the intra-specific crosses. It is a bigger plant and autogamous, and previous studies indicated that selfing forces the asymmetric formation of sterile hybrids. All these characteristics help C. seridis to avoid the minority-cytotype-exclusion effect and become established. Inter-specific hybridization was possible between C. aspera and C. gentilii, and with the symmetric formation of hybrids. However, 49% of the hybrid cypselae were empty, which probably reveals postzygotic barriers. Autotetraploid C. gentilii produced the same number of cypselae per capitulum as those of the diploid parental, has an indistinguishable field phenotype, is allogamous, and symmetrically produces hybrids. Therefore, C. gentilii does not seem to have the same competitive advantages as those of C. seridis.

Interspecific Hybridization Between Common Ragweed (Ambrosia artemisiifolia) and Giant Ragweed (A. trifida)

Weed Science ◽  
1987 ◽  
Vol 35 (5) ◽  
pp. 633-636 ◽  
Author(s):  
Gilles Vincent ◽  
Mario Cappadocia
Keyword(s):  
Ambrosia Artemisiifolia ◽  
Eastern Canada ◽  
Common Ragweed ◽  
Future Studies ◽  
Suitable Material ◽  
Culture Techniques ◽  
Hybrid Plants ◽  
Giant Ragweed ◽  
Postzygotic Barriers ◽  
Embryo Culture Techniques

Common ragweed [Ambrosia artemisiifoliaL. # AMBEL (2n=36)] and giant ragweed[A. trifidaL. # AMBTR (2n=24)] are two abundant annuals that are widespread throughout northeastern North America. They are also the main cause of hay fever in Eastern Canada. The formation of a hybrid between the two species has been reported only once and just one type of hybrid was recovered; namely, common ragweed × giant ragweed. In order to create additional suitable material for future studies of the biochemical features characterizing the allergenic pollen, the production of reciprocal hybrids between common and giant ragweed was attempted. A number of hybrid plants derived from crosses of the type common ragweed × giant ragweed were easily obtained; the reciprocal crosses, however, failed to produce viable plants. In this last case, evidence of postzygotic barriers of interspecific incompatibility were shown by the presence of underdeveloped embryos contained in the few seeds recovered. Embryo culture techniques, therefore, were used in order to bypass such barriers. By this method fifteen plants of hybrid constitution survived to maturity.

scholarly journals Male-Female Interactions and the Evolution of Postmating Prezygotic Reproductive Isolation among Species of the Virilis Subgroup

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Nada Sagga ◽  
Alberto Civetta
Keyword(s):  
Reproductive Isolation ◽  
Egg Laying ◽  
Sperm Transfer ◽  
Geographic Locations ◽  
Future Studies ◽  
Egg Hatchability ◽  
Fertilization Rates ◽  
Postzygotic Barriers ◽  
Storage Organs

Reproductive isolation reduces breeding between species. Traditionally, prezygotic and postzygotic barriers to reproduction have been broadly studied, but in recent years, attention has been brought to the existence of barriers that act after copulation but before fertilization. Here, we show that when D. virilis females from different geographic locations mate with D. novamexicana males, egg laying is normal, but fertilization rates are severely reduced, despite normal rates of sperm transfer. This reduction in fertilization is probably due to lower retention of heterospecific sperm in female storage organs one-to-two days after copulation. An inspection of egg hatchability in crosses between females and males from other virilis subgroup species reveals that isolation due to poor egg hatchability likely evolved during the diversification of D. virilis/D. lummei from species of the novamexicana-americana clade. Interestingly, the number of eggs laid by D. virilis females in heterospecific crosses was not different from the numbers of eggs laid in conspecific crosses, suggesting that females exert some form of cryptic control over the heterospecific ejaculate and that future studies should focus on how female and female-sperm interactions contribute to the loss or active exclusion of heterospecific sperm from storage.

scholarly journals Crossability Between Wild (Malus sylvestris) and Cultivated (M. x domestica) Apples

2008 ◽  
Vol 57 (1-6) ◽  
pp. 127-130 ◽  
Author(s):  
A. S. Larsen ◽  
M. Jensen ◽  
E. D. Kjær
Keyword(s):  
Genetic Resources ◽  
Seed Production ◽  
Fruit Set ◽  
Fruit Tree ◽  
Malus X Domestica ◽  
Malus Sylvestris ◽  
Postzygotic Barriers

Abstract Malus sylvestris, a native fruit tree of Europe, is believed to be threatened by hybridization with the omnipresent cultivated apple (Malus x domestica). In the present study a series of controlled crossings were carried out in order to establish whether M. sylvestris can hybridize with its near relative, M. x domestica. By looking at fruit set, seed production, germination percentages, and development of seedlings following inter- and intraspecific crossings, no indication of neither pre- nor postzygotic barriers to hybridization between the two species was found. This can have important implications for management of the genetic resources of M. sylvestris.

Maintenance of asymmetric hybridization between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) via postzygotic barriers and paternal effects

2011 ◽  
Vol 68 (4) ◽  
pp. 593-602 ◽  
Author(s):  
David Álvarez ◽  
Eva Garcia-Vazquez
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Developmental Rate ◽  
Paternal Effects ◽  
Atlantic Salmon Salmo Salar ◽  
Postzygotic Barriers ◽  
Brown Trout Salmo Trutta ◽  
In The Wild

At the southern European edge of Atlantic salmon ( Salmo salar ) distribution, all the hybrids found in nature are the product of crosses between female salmon and male brown trout ( Salmo trutta ). By artificially producing reciprocal crosses between salmon and trout, we demonstrate that unidirectional hybridization observed in nature is the result of postzygotic barriers that produce very high mortality rates (95%) in female trout × male salmon hybrids and not the consequence of prezygotic isolation or behavioural differences between the two species. Mortality of female trout × male salmon hybrids mainly occurs during the last phases of development, and a high percentage of these surviving hybrids showed external deformities that could compromise survival in the wild. Another important finding is the existence of paternal factor in embryo development. Using time to midhatch as an indicator of developmental rate, female salmon × male trout hybrids hatched faster than female trout × male salmon hybrids, with both developing at a rate intermediate to the pure crosses. The early emergence of female salmon × male trout hybrids, which have similar survival to pure salmons, could have fitness repercussions, since early emerging fry have a competitive advantage over later emerging fry.

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