scholarly journals Selection in parental species predicts hybrid evolution

2018 ◽  
Author(s):  
Anna Runemark ◽  
Richard I Bailey ◽  
Lena Bache-Mathiesen ◽  
Glenn-Peter Sætre
Keyword(s):  
Species Differences ◽  
Parental Species ◽  
Phenotypic Trait ◽  
Parent Species ◽  
Plumage Color ◽  
Trait Variation ◽  
Island Populations ◽  
Homoploid Hybrid ◽  
Phenotypic Novelty ◽  
Major Qtl

AbstractWhile hybridization is recognized as important in evolution, its contribution to adaptation and diversification remains poorly understood. Using genomically diverged island populations of the homoploid hybrid Italian sparrow, we test predictions for phenotypic trait values and evolvability based on patterns of parental species divergence in four plumage color traits. We find associations between parental divergence and trait evolution in Italian sparrows. Fixed major QTL in species differences lead to hybrids with higher trait variation, and hence evolvability, than the parent species. Back and crown plumage show no correlation between current within-parent variability and among-parent differentiation. For these traits, Italian sparrow phenotypes are biased towards axes of high parental differentiation and show greater phenotypic novelty along axes of low current parental evolvability, as predicted when major QTL are involved in species differences. Crown color has consistently evolved back towards one parent, while back color varies among islands. We also find significant among-population diversification within the Italian sparrow. Hence, hybridization of the same parent species can generate different phenotypes. In conclusion, we find support for parental phenotypic divergence patterns reflecting divergence mechanisms, and hence such patterns can be useful in predicting how hybridization alters the potential to evolve and adapt.

scholarly journals Variation and constraints in hybrid genome formation

2017 ◽  
Author(s):  
Anna Runemark ◽  
Cassandra N. Trier ◽  
Fabrice Eroukhmanoff ◽  
Jo S. Hermansen ◽  
Michael Matschiner ◽  
...  
Keyword(s):  
Dna Repair ◽  
Nuclear Genes ◽  
Species Boundaries ◽  
Z Chromosome ◽  
Parent Species ◽  
Island Populations ◽  
Hybrid Genome ◽  
Adaptive Radiations ◽  
Homoploid Hybrid ◽  
Genomic Regions

SummaryRecent genomic investigations have revealed hybridization to be an important source of variation, the working material of natural selection1,2. Hybridization can spur adaptive radiations3, transfer adaptive variation across species boundaries4, and generate species with novel niches5. Yet, the limits to viable hybrid genome formation are poorly understood. Here we investigated to what extent hybrid genomes are free to evolve or whether they are restricted to a specific combination of parental alleles by sequencing the genomes of four isolated island populations of the homoploid hybrid Italian sparrow Passer italiae6,7. Based on 61 Italian sparrow genomes from Crete, Corsica, Sicily and Malta, and 10 genomes of each of the parent species P. domesticus and P. hispaniolensis, we report that a variety of novel and fully functional hybrid genomic combinations have arisen on the different islands, with differentiation in candidate genes for beak shape and plumage colour. There are limits to successful genome fusion, however, as certain genomic regions are invariably inherited from the same parent species. These regions are overrepresented on the Z-chromosome and harbour candidate incompatibility loci, including DNA-repair and mito-nuclear genes; loci that may drive the general reduction of introgression on sex chromosomes8. Our findings demonstrate that hybridization is a potent process for generating novel variation, but variation is limited by DNA-repair and mito-nuclear genes, which play an important role in reproductive isolation and thus contribute to speciation.

scholarly journals Phenotypic Trait Variation as a Response to Altitude-Related Constraints in Arabidopsis Populations

2019 ◽  
Vol 10 ◽  
Author(s):  
Harold Duruflé ◽  
Philippe Ranocha ◽  
Duchesse Lacour Mbadinga Mbadinga ◽  
Sébastien Déjean ◽  
Maxime Bonhomme ◽  
...  
Keyword(s):  
Phenotypic Trait ◽  
Trait Variation

scholarly journals Hybridization History and Repetitive Element Content in the Genome of a Homoploid Hybrid, Yucca gloriosa (Asparagaceae)

2021 ◽  
Vol 11 ◽  
Author(s):  
Karolina Heyduk ◽  
Edward V. McAssey ◽  
Jane Grimwood ◽  
Shengqiang Shu ◽  
Jeremy Schmutz ◽  
...  
Keyword(s):  
Parental Species ◽  
Expression Patterns ◽  
Hybrid Plant ◽  
Sequencing Data ◽  
Hybrid Species ◽  
Chloroplast Genomes ◽  
Important Trait ◽  
Homoploid Hybrid ◽  
Whole Genome Resequencing ◽  
Expression Evidence

Hybridization in plants results in phenotypic and genotypic perturbations that can have dramatic effects on hybrid physiology, ecology, and overall fitness. Hybridization can also perturb epigenetic control of transposable elements, resulting in their proliferation. Understanding the mechanisms that maintain genomic integrity after hybridization is often confounded by changes in ploidy that occur in hybrid plant species. Homoploid hybrid species, which have no change in chromosome number relative to their parents, offer an opportunity to study the genomic consequences of hybridization in the absence of change in ploidy. Yucca gloriosa (Asparagaceae) is a young homoploid hybrid species, resulting from a cross between Yucca aloifolia and Yucca filamentosa. Previous analyses of ∼11 kb of the chloroplast genome and nuclear-encoded microsatellites implicated a single Y. aloifolia genotype as the maternal parent of Y. gloriosa. Using whole genome resequencing, we assembled chloroplast genomes from 41 accessions of all three species to re-assess the hybrid origins of Y. gloriosa. We further used re-sequencing data to annotate transposon abundance in the three species and mRNA-seq to analyze transcription of transposons. The chloroplast phylogeny and haplotype analysis suggest multiple hybridization events contributing to the origin of Y. gloriosa, with both parental species acting as the maternal donor. Transposon abundance at the superfamily level was significantly different between the three species; the hybrid was frequently intermediate to the parental species in TE superfamily abundance or appeared more similar to one or the other parent. In only one case—Copia LTR transposons—did Y. gloriosa have a significantly higher abundance relative to either parent. Expression patterns across the three species showed little increased transcriptional activity of transposons, suggesting that either no transposon release occurred in Y. gloriosa upon hybridization, or that any transposons that were activated via hybridization were rapidly silenced. The identification and quantification of transposon families paired with expression evidence paves the way for additional work seeking to link epigenetics with the important trait variation seen in this homoploid hybrid system.

scholarly journals Un nuevo híbrido en el género Antirrhinum L. (Plantaginaceae, Antirrhineae Chav.). A new hybrid in the genre Antirrhinum L. (Plantaginaceae, Antirrhineae Chav.). 

2016 ◽  
Vol 41 ◽  
pp. 155-162
Author(s):  
P. Pablo Ferrer-Gallego ◽  
Roberto Roselló ◽  
Emilio Laguna ◽  
Jaime Güemes
Keyword(s):  
Parental Species ◽  
Culture Conditions ◽  
Parent Species ◽  
Diagnostic Characters ◽  
Forestry Research ◽  
Spontaneous Process

Español.  Se describe Antirrhinum × inexpectans, hybr. nov. (Plantaginaceae, Antirrhineae Chav.) producto del cruzamiento espontáneo, en condiciones de cultivo, entre A. mollissimum (Pau) Rothm. y A. tortuosum Bosc ex Vent. Este híbrido ha sido localizado en los viveros del Centro para la Investigación y Experimentación Forestal-CIEF de la Generalitat Valenciana (Quart de Poblet, València, España) donde se han cultivado durante varios años los parentales, lo que ha permitido el proceso de hibridación espontánea entre ambos. Junto a la descripción y diagnosis de esta planta, se aporta una lámina y una tabla con los principales caracteres diagnósticos para diferenciarlo de las especies de las que procede.Inglés.  Antirrhinum × inexpectans, hybr. nov. (Plantaginaceae, Antirrhineae Chav.) is described herein coming from the spontaneous crossing, in culture conditions, between A. mollissimum (Pau) Rothm. and A. tortuosum Bosc ex Vent.: A. × inexpectans, hybr. nov. This hybrid has been found in the nurseries of the Centre for Forestry Research and Experimentation-CIEF of the Generalitat Valenciana (Quart de Poblet, Valencia, Spain). In this center, the culture of the two parent species for several years has allowed the spontaneous process of hybridization. A plant description and diagnosis, iconography and a table showing the main diagnostic characters to differentiate it from the two parental species is provided. 

Sorting out the muddle: taxonomy and nomenclature of Thymus ×porcii (Lamiaceae) and related nothotaxa, with comments on parent species delimitation

Phytotaxa ◽  
2021 ◽  
Vol 501 (1) ◽  
pp. 119-139
Author(s):  
VIKTOR O. NACHYCHKO ◽  
YEVHEN V. SOSNOVSKY
Keyword(s):  
Species Delimitation ◽  
Parental Species ◽  
Molecular Data ◽  
Forest Steppe ◽  
Original Material ◽  
Parent Species ◽  
Natural Hybrid ◽  
Separate Species ◽  
Diagnostic Traits

Thymus ×porcii is a natural hybrid between T. pannonicus and T. pulegioides, occurring within the co-occurrence range of its parental species in the forest and forest-steppe zones of Europe. Taxonomy and nomenclature of this hybrid present a longstanding puzzle due to the lack of critical evaluations of the original material as well as conflicting taxonomic interpretations of the parent taxa both at specific and intraspecific levels. The present paper attempts to clarify these issues, arguing against the synonymic treatment and/or consolidation of T. pannonicus and T. pulegioides, which is accepted in modern taxonomies apparently as a result of nomenclatural confusion related to T. pannonicus typification. Based on morphology and reported molecular data, it is proposed to treat T. pannonicus and T. pulegioides as separate species, each containing two varieties being well-distinguished by the presence or absence of leaf indumentum: T. pannonicus var. latifolius (glabrous leaves) and T. pannonicus var. pannonicus (pubescent leaves), and T. pulegioides var. pulegioides (glabrous leaves) and T. pulegioides var. vestitus (pubescent leaves). In view of such treatment, T. ×porcii is divided into three nothovarieties, representing natural crosses between different varieties of the parent species. Namely, in addition to the typical T. ×porcii nothovar. porcii [T. pannonicus var. latifolius × T. pulegioides var. pulegioides] (with T. ×pilisiensis and T. ×goginae as the taxonomic synonyms), we describe a new nothovariety T. ×porcii nothovar. calvariensis [T. pannonicus var. pannonicus × T. pulegioides var. pulegioides], and propose a new nomenclatural combination T. ×porcii nothovar. opizii [T. pannonicus × T. pulegioides var. vestitus] based on the previously published name T. ×opizii. On the basis of original material examination, two collections from BP are designated here as the lectotypes of T. ×porcii (≡ T. ×porcii nothovar. porcii) and T. ×pilisiensis respectively, and one specimen from PR is designated as the lectotype of T. ×opizii (≡ T. ×porcii nothovar. opizii). Main diagnostic traits of T. ×porcii nothovarieties and their parental taxa are compared and discussed.

scholarly journals Geographical and environmental gradients shape phenotypic trait variation and genetic structure inPopulus trichocarpa

2013 ◽  
Vol 201 (4) ◽  
pp. 1263-1276 ◽  
Author(s):  
Athena D. McKown ◽  
Robert D. Guy ◽  
Jaroslav Klápště ◽  
Armando Geraldes ◽  
Michael Friedmann ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Environmental Gradients ◽  
Phenotypic Trait ◽  
Trait Variation

scholarly journals Genetic divergence and the number of hybridizing species affect the path to homoploid hybrid speciation

2018 ◽  
Vol 115 (39) ◽  
pp. 9761-9766 ◽  
Author(s):  
Aaron A. Comeault ◽  
Daniel R. Matute
Keyword(s):  
Genetic Diversity ◽  
Reproductive Isolation ◽  
Genetic Divergence ◽  
Adaptive Systems ◽  
Parental Species ◽  
Hybrid Speciation ◽  
Hybrid Species ◽  
Empirical Question ◽  
Homoploid Hybrid

Hybridization is often maladaptive and in some instances has led to the loss of biodiversity. However, hybridization can also promote speciation, such as during homoploid hybrid speciation, thereby generating biodiversity. Despite examples of homoploid hybrid species, the importance of hybridization as a speciation mechanism is still widely debated, and we lack a general understanding of the conditions most likely to generate homoploid hybrid species. Here we show that the level of genetic divergence between hybridizing species has a large effect on the probability that their hybrids evolve reproductive isolation. We find that populations of hybrids formed by parental species with intermediate levels of divergence were more likely to mate assortatively, and discriminate against their parental species, than those generated from weakly or strongly diverged parental species. Reproductive isolation was also found between hybrid populations, suggesting differential sorting of parental traits across populations. Finally, hybrid populations derived from three species were more likely to evolve reproductive isolation than those derived from two species, supporting arguments that hybridization-supplied genetic diversity can lead to the evolution of novel “adaptive systems” and promote speciation. Our results illustrate when we expect hybridization and admixture to promote hybrid speciation. Whether homoploid hybrid speciation is a common speciation mechanism in general remains an outstanding empirical question.

scholarly journals Hybridization and genome evolution I: The role of contingency during hybrid speciation

2013 ◽  
Vol 59 (5) ◽  
pp. 667-674 ◽  
Author(s):  
Fabrice Eroukhmanoff ◽  
Richard I. Bailey ◽  
Glenn-Peter Sætre
Keyword(s):  
Chromosome Number ◽  
Genome Evolution ◽  
Hybrid Speciation ◽  
Parent Species ◽  
Large Role ◽  
Hybrid Species ◽  
Intragenomic Conflict ◽  
Hybrid Swarms ◽  
Homoploid Hybrid

Abstract Homoploid hybrid speciation (HHS) involves the recombination of two differentiated genomes into a novel, functional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recombine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these “hopeful monsters” of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic contributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions (competition, geography of the contact zones or the initial frequency of both parent species) might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puzzle.

scholarly journals The relation of meiotic behaviour to hybridity, polyploidy and apomixis in the Ranunculus auricomus complex (Ranunculaceae)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Birthe H. Barke ◽  
Kevin Karbstein ◽  
Mareike Daubert ◽  
Elvira Hörandl
Keyword(s):  
Parental Species ◽  
Hybrid Sterility ◽  
Male Meiosis ◽  
Developmental Changes ◽  
Female Meiosis ◽  
Developmental Abnormalities ◽  
Selective Pressures ◽  
Hybrid Plants ◽  
Homoploid Hybrid ◽  
Chromatin Bridges

Abstract Background Hybridization and polyploidization are powerful evolutionary factors that are associated with manifold developmental changes in plants such as irregular progression of meiosis and sporogenesis. The emergence of apomixis, which is asexual reproduction via seeds, is supposed to be connected to these factors and was often regarded as an escape from hybrid sterility. However, the functional trigger of apomixis is still unclear. Recently formed di- and polyploid Ranunculus hybrids, as well as their parental species were analysed for their modes of mega- and microsporogenesis by microscopy. Chromosomal configurations during male meiosis were screened for abnormalities. Meiotic and developmental abnormalities were documented qualitatively and collected quantitatively for statistical evaluations. Results Allopolyploids showed significantly higher frequencies of erroneous microsporogenesis than homoploid hybrid plants. Among diploids, F2 hybrids had significantly more disturbed meiosis than F1 hybrids and parental plants. Chromosomal aberrations included laggard chromosomes, chromatin bridges and disoriented spindle activities. Failure of megasporogenesis appeared to be much more frequent in than of microsporogenesis is correlated to apomixis onset. Conclusions Results suggest diverging selective pressures on female and male sporogenesis, with only minor effects of hybridity on microsporogenesis, but fatal effects on the course of megasporogenesis. Hence, pollen development continues without major alterations, while selection will favour apomixis as alternative to the female meiotic pathway. Relation of investigated errors of megasporogenesis with the observed occurrence of apospory in Ranunculus hybrids identifies disturbed female meiosis as potential elicitor of apomixis in order to rescue these plants from hybrid sterility. Male meiotic disturbance appears to be stronger in neopolyploids than in homoploid hybrids, while disturbances of megasporogenesis were not ploidy-dependent.

scholarly journals Within-Population Trait Variation in a Globally Invasive Plant Species Mayweed Chamomile (Anthemis cotula): Implications for Future Invasion and Management

2021 ◽  
Vol 3 ◽  
Author(s):  
Subodh Adhikari ◽  
Ian C. Burke ◽  
Samuel R. Revolinski ◽  
Julia Piaskowski ◽  
Sanford D. Eigenbrode
Keyword(s):  
Cover Crops ◽  
Management Practices ◽  
Invasive Plant ◽  
Floral Scent ◽  
Seedling Emergence ◽  
Phenotypic Trait ◽  
Phenotypic Traits ◽  
Trait Variation ◽  
Invasion Mechanisms ◽  
Sib Families

Quantification of variation for phenotypic traits within and among weed populations facilitate understanding of invasion mechanisms and management tactics. In the Pacific Northwest (PNW), USA, in response to climate change and to improve sustainability, producers are increasingly adopting broadleaf crops and cover crops, but Mayweed chamomile (Anthemis cotula L.) is a significant barrier to diversifying cropping systems because of its abundance and lack of herbicide options for its control. To quantify within-population phenotypic trait variation and heritability, plants (n = 300) from six half-sib families (i.e., seed source plants or mother plants) from each of 10 A. cotula populations (infested farms or sites) in the PNW were grown from seed through the flowering stage in the greenhouse common garden experiment. We measured percent seedling emergence, the initial date of flowering, flowering duration, plant biomass, number of flower heads, floral scent profiles, and other traits on individual plants. Trait variation was high among half-sib families within each population. For example, in two of the populations, percent seedling emergence within 30 days of planting ranged from 5 to 41% and 3 to 53%, respectively. As another example, initial date of flowering in two other populations ranged from 61 to 93 days and 58 to 92 days, respectively. Differences among half-sib families were greatest for flowering period, which differed by a month in most populations, and floral scent profiles. Heritability estimates were higher than 1.0 for most phenotypic traits, indicating that the study plants were more closely related than half-sibs (i.e., included full-sibs or products of selfing). These patterns of phenotypic trait variation are potentially caused by local edaphoclimatic factors and within-field farm management practices, suggesting that management of A. cotula might be challenging and differ within and across farms.

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