scholarly journals Locus‐specific introgression in young hybrid swarms: drift may dominate selection

2021 ◽  
Author(s):  
S. Eryn McFarlane ◽  
Helen V. Senn ◽  
Stephanie L. Smith ◽  
Josephine M. Pemberton
Keyword(s):  
Hybrid Swarms

Population Dynamics and Regeneration of a Hybrid Zone Between Eucalyptus risdonii Hook-F and E amygdalina Labill

1986 ◽  
Vol 34 (3) ◽  
pp. 305 ◽  
Author(s):  
BM Potts
Keyword(s):  
Hybrid Zone ◽  
Null Point ◽  
Asymmetric Distribution ◽  
Hybrid Swarm ◽  
Population Response ◽  
Pure Species ◽  
Seed Migration ◽  
Hybrid Swarms ◽  
Population Turnover ◽  
Phenotypic Fitness

Regeneration of a hybrid zone between E. amygdalina and E. risdonii and pure species stands following wildfire is reported, as well as the reproductive and vegetative fitness of parental and hybrid phenotypes. E. risdonii phenotypes dominated the seed rain and seedling cohort and there was clearly a marked fitness differential between E. amygdalina and E. risdonii at their boundary. When the F1 type hybrid is in competition with both parental types it is generally reproductively the least fit, although frequently vegetatively vigorous. Reduced fitness appears to extend to advanced generations as hybrid phenotypes tending.toward either species are, on average, less fit than the corresponding parental type. The pattern of phenotypic fitness suggests that the species' boundary is in disequilibrium and it is argued that E. risdonii is invading the range of E. amygdalina by both pollen and seed migration. There is an asymmetric distribution of F1 type hybrids across the boundary and the hybrid swarm examined is being invaded by E. risdonii genes. It is suggested that hybridization may be associated with natural disequilibrium and, where seed migration is limited, boundary movements may be preceded by a wave of hybridization due partly to pollen swamping of the least fit species. Hybrid swarms may develop but, at the boundary of large stands, are probably transitory. There is a marked inertia in the population response to the prevailing selective regime due to the extremely slow population turnover and limited dispersal potential. This is discussed in the broader context of non-equilibrium models where it is argued that dispersal may be the factor limiting population response to perturbation of a shallow environmental gradient. This is due to large geographical shifts in the position of the null point and would be accentuated in a patchy environment where migration as a front is prevented.

scholarly journals From Hybrid Swarms to Swarms of Hybrids

2014 ◽  
Vol 2 (8) ◽  
pp. 311-318 ◽  
Author(s):  
Thomas J. Stohlgren ◽  
Allen L. Szalanski ◽  
John Gaskin ◽  
Nicholas Young ◽  
Amanda West ◽  
...  
Keyword(s):  
Hybrid Swarms

Geographic Patterns of Interspecific Hybridization between Spotted Knapweed (Centaurea stoebe) and Diffuse Knapweed (C. diffusa)

2009 ◽  
Vol 2 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Amy C. Blair ◽  
Ruth A. Hufbauer
Keyword(s):  
North America ◽  
North American ◽  
Management Strategies ◽  
Spotted Knapweed ◽  
The North ◽  
Hybrid Swarms ◽  
Hybrid Plants ◽  
Introduced Range ◽  
Diffuse Knapweed ◽  
A Site

AbstractHybridization between species has the potential to change invasion dynamics. Field observations suggest that spotted knapweed and diffuse knapweed, two ecologically and economically destructive invasive plants, hybridize in their introduced range. As a first step towards understanding whether hybridization has affected the dynamics of the invasion of these species, we conducted field surveys in the introduced (North American) and native (European) ranges to discern patterns of hybridization and measured fitness-related traits among field hybrids and parental species. In North America we detected plants with hybrid morphology in 97% of the diffuse knapweed sites (n= 40); such hybrid plants were taller and more often exhibited polycarpy than plants with typical diffuse knapweed morphology. Hybrids were not detected in North American spotted knapweed sites (n= 22). In most regions surveyed in Europe, diffuse knapweed and spotted knapweed were isolated from each other and existed as distinct, nonhybridizing species. However, in Ukraine, the two species frequently coexisted within a site, resulting in hybrid swarms. On average, the plants from the North American diffuse knapweed sites (including plants with both diffuse and hybrid morphology), were larger than the apparently pure diffuse knapweed in the native range. The cross-continental patterns of hybridization likely are explained by differences in cytology. It recently has been confirmed that the spotted knapweed in North America is tetraploid whereas the diffuse knapweed is diploid. Genetic incompatibilities associated with these two cytotypes likely prevent ongoing hybridization. We hypothesize that hybrid individuals were introduced to North America along with diffuse knapweed. Because plants with hybrid morphology are found in nearly all North American diffuse knapweed sites, the introduction of hybrids likely occurred early in the invasion of diffuse knapweed. Thus, although the presence of hybrids might facilitate the ongoing invasion of diffuse knapweed into North America, elevated concern regarding their presence might not be warranted. Because such individuals are not likely to represent a new hybridization event, currently effective management strategies used in diffuse knapweed sites should not need alteration.

Variation in fiber cables in the lacunae of leaves in hybrid swarms of Typha×glauca

2015 ◽  
Vol 124 ◽  
pp. 39-44 ◽  
Author(s):  
Allan Witztum ◽  
Randy Wayne
Keyword(s):  
Hybrid Swarms ◽  
Typha Glauca

Hybrid Swarms Optimization Based Image Segmentation

2016 ◽  
pp. 1-21 ◽  
Author(s):  
Mohamed Abd El Aziz ◽  
Ahmed A. Ewees ◽  
Aboul Ella Hassanien
Keyword(s):  
Image Segmentation ◽  
Hybrid Swarms

Genetic status of the putative hybrid swarms of mountain dwarf pine and Scots pine in contact zones of their distribution in Slovakia

Biologia ◽  
2015 ◽  
Vol 70 (10) ◽  
Author(s):  
Peter Maňka ◽  
Andrej Kormuťák ◽  
Martin Galgóci ◽  
Dušan Gömöry
Keyword(s):  
Genetic Structure ◽  
Scots Pine ◽  
Molecular Level ◽  
Natural Populations ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Hybrid Swarm ◽  
Pure Species ◽  
Hybrid Swarms ◽  
History Of

AbstractGenetic structure of the mountain dwarf pine (Pinus mugo) and Scots pine (P. sylvestris) natural populations along with their 4 putative hybrid swarms in Slovakia were analyzed using 12 enzyme loci. The study aimed in evaluation of postulated hybrid status of the swarms on molecular level. Based on semidiagnostic allele frequencies of the MDH B, MDH C, 6PGDH B, ADH 1 and F-EST loci in their megagametophytes and vegetative buds, the conspicuous genetic differences were detected between P. mugo and P. sylvestris populations. The putative hybrid swarms seem to incline by their genetic structure to P. mugo rather than to P. sylvestris. Obtained results indicate independent developmental history of each of the scored hybrid swarms. The putative hybrid swarm in Sucha Hora was found to be a mixed stand consisting prevailingly of pure-species individuals of P. mugo and P. sylvestris. On the contrary, the putative hybrid swarms in Habovka, Tisovnica and Terchova are supposed to be of hybrid origin.

THE GENOMIC TRAJECTORY OF HYBRID SWARMS: OUTCOMES OF REPEATED CROSSES BETWEEN POPULATIONS OFTIGRIOPUS CALIFORNICUS

Evolution ◽  
2012 ◽  
Vol 67 (3) ◽  
pp. 774-791 ◽  
Author(s):  
Victoria L. Pritchard ◽  
Suzanne Edmands
Keyword(s):  
Hybrid Swarms

scholarly journals Analysis of suspected hybrid swarms in the genus Eucalyptus

Heredity ◽  
1954 ◽  
Vol 8 (2) ◽  
pp. 259-269 ◽  
Author(s):  
H T Clifford
Keyword(s):  
Hybrid Swarms ◽  
Genus Eucalyptus

Hybrid Swarms Between Wild and Cultivated Rice Species, Oryza perennis and O. sativa

Evolution ◽  
1961 ◽  
Vol 15 (4) ◽  
pp. 418 ◽  
Author(s):  
Hiko-Ichi Oka ◽  
Wen-Tsai Chang
Keyword(s):  
Cultivated Rice ◽  
Hybrid Swarms ◽  
Oryza Perennis
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