Genomic introgression from a distant congener in the Levant fritillary butterfly, Melitaea acentria

2021 ◽  
Author(s):  
Elena A. Pazhenkova ◽  
Vladimir A. Lukhtanov
Keyword(s):  
Genomic Introgression

scholarly journals Restricted X chromosome introgression and support for Haldane's rule in hybridizing damselflies

2021 ◽  
Author(s):  
Janne Swaegers ◽  
Rosa Ana Sanchez-Guillen ◽  
Pallavi Chauhan ◽  
Maren Wellenreuther ◽  
Bengt Hansson
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Hybrid Zones ◽  
Haldane’S Rule ◽  
Haldane's Rule ◽  
Genome Wide ◽  
Determination System ◽  
Heterogametic Sex ◽  
Sex Determination System ◽  
Genomic Introgression

Contemporary hybrid zones act as natural laboratories for the investigation of species boundaries and allow to shed light on the little understood roles of sex chromosomes in species divergence. Sex chromosomes are considered to function as a hotspot of genetic divergence between species; indicated by less genomic introgression compared to autosomes during hybridisation. Moreover, they are thought to contribute to Haldane's rule which states that hybrids of the heterogametic sex are more likely to be inviable or sterile. To test these hypotheses, we used contemporary hybrid zones of Ischnura elegans, a damselfly species that has been expanding its range into the northern and western regions of Spain, leading to chronic hybridization with its sister species Ischnura graellsii. We analysed genome-wide SNPs in the Spanish I. elegans and I. graellsii hybrid zone and found (i) that the X chromosome shows less genomic introgression compared to autosomes and (ii) that males are underrepresented among admixed individuals as predicted by Haldane's rule. This is the first study in Odonata that suggests a role of the X chromosome in reproductive isolation. Moreover, our data adds to the few studies on species with X0 sex determination system and contradicts the hypothesis that the absence of a Y chromosome causes exceptions to Haldane's rule.

scholarly journals Alternative facts: a reconsideration of putatively natural interspecific hybrid specimens in the genus Heliconius (Lepidoptera: Nymphalidae)

Zootaxa ◽  
2018 ◽  
Vol 4499 (1) ◽  
pp. 1 ◽  
Author(s):  
ANDREW V. Z. BROWER
Keyword(s):  
Interspecific Hybrid ◽  
Interspecific Hybrids ◽  
Evolutionary Biology ◽  
Putative Hybrid ◽  
Actual Number ◽  
Closely Related Species ◽  
Alternative Facts ◽  
Chain Of Custody ◽  
Alternative Species ◽  
Genomic Introgression

Mallet et al. (2007 BMC Evolutionary Biology, 7, 28) employed a database of putative interspecific hybrid specimens of the genus Heliconius to advance a hypothesis of "the species boundary as a continuum." Here, each of those specimens, as well as subsequently documented specimens, is individually reassessed regarding its phenotype, potential parentage and chain of custody in collections. Using a quantified scale of reliability, most of the specimens are interpreted differently than Mallet et al.'s identifications, and the actual number of interspecific hybrids is estimated to be much smaller than they proposed. To be specific, of 163 putative hybrid specimens examined, 11% suffered from ambiguous identity, 5% from confounding issues with their data labels, 50% were arguably intraspecific (depending upon alternative species concepts), and 22% were almost certainly reared, commercial specimens. Only eleven of the specimens meet the criteria established here to be legitimate and reliable interspecific hybrids, and all of those are between closely-related species. This result has potentially important implications for current hypotheses of frequent genomic introgression of wing pattern alleles among Heliconius clades. 

scholarly journals An Integrative Approach to Genomic Introgression Mapping

2010 ◽  
Vol 154 (1) ◽  
pp. 3-12 ◽  
Author(s):  
Andrew J. Severin ◽  
Gregory A. Peiffer ◽  
Wayne W. Xu ◽  
David L. Hyten ◽  
Bruna Bucciarelli ◽  
...  
Keyword(s):  
Integrative Approach ◽  
Genomic Introgression

scholarly journals Low Correlation Between Genomic and Morphological Introgression Estimates in a Walnut Backcross

1998 ◽  
Vol 123 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Keith Woeste ◽  
Gale McGranahan ◽  
Robert Bernatzky
Keyword(s):  
Fragment Length Polymorphism ◽  
Parental Species ◽  
Juglans Regia ◽  
Linkage Data ◽  
Recurrent Parent ◽  
Morphological Similarity ◽  
Randomly Amplified Polymorphic Dna ◽  
Backcross Population ◽  
Juglans Hindsii ◽  
Genomic Introgression

A first backcross population of walnuts {[Juglans hindsii (Jeps.) Jeps. × Juglans regia L.] × J. regia} was used to evaluate the correlation between morphological (statistical) and genetic distance during introgression. Five traits based on leaf morphology were identified to quantitate the morphology of the parental species, their F1 hybrids, and the backcrosses to each parent. These traits were used to evaluate the morphological similarity of first backcrosses to J. regia using Mahalanobis' distance. The amount of genomic introgression of each backcross was estimated using 59 randomly amplified polymorphic DNA (RAPD) and 41 restriction fragment-length polymorphism (RFLP) genetic markers that identify polymorphisms between J. regia and J. hindsii. A smaller scaffold set of markers was also identified using published linkage data. The correlation between the measures of morphological and genomic introgression for the first backcrosses was low (0.23) but significant. The results suggest that selection based on morphology during backcrossing will not be an effective way to recover recurrent parent genome.

Biodiversity genomics of North American Dryobates woodpeckers reveals little gene flow across the D. nuttallii x D. scalaris contact zone

The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Joseph D Manthey ◽  
Stéphane Boissinot ◽  
Robert G Moyle
Keyword(s):  
Gene Flow ◽  
Contact Zone ◽  
Genomic Diversity ◽  
Whole Genome ◽  
Effective Population ◽  
Contact Zones ◽  
Population Sizes ◽  
Speciation Continuum ◽  
Whole Genome Resequencing ◽  
Genomic Introgression

Abstract Evolutionary biologists have long used behavioral, ecological, and genetic data from contact zones between closely related species to study various phases of the speciation continuum. North America has several concentrations of avian contact zones, where multiple pairs of sister lineages meet, with or without hybridization. In a southern California contact zone, 2 species of woodpeckers, Nuttall’s Woodpecker (Dryobates nuttallii) and the Ladder-backed Woodpecker (D. scalaris), occasionally hybridize. We sampled these 2 species in a transect across this contact zone and included samples of their closest relative, the Downy Woodpecker (D. pubescens), to obtain large single nucleotide polymorphism panels using restriction-site associated DNA sequencing (RAD-seq). Furthermore, we used whole-genome resequencing data for 2 individuals per species to identify whether patterns of diversity inferred from RAD-seq were representative of whole-genome diversity. We found that these 3 woodpecker species are genomically distinct. Although low levels of gene flow occur between D. nuttallii and D. scalaris across the contact zone, there was no evidence for widespread genomic introgression between these 2 species. Overall patterns of genomic diversity from the RAD-seq and wholegenome datasets appear to be related to distributional range size and, by extension, are likely related to effective population sizes for each species.

scholarly journals Whole-Genome Sequencing of Trypanosoma brucei Reveals Introgression between Subspecies That Is Associated with Virulence

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Ian Goodhead ◽  
Paul Capewell ◽  
J. Wendi Bailey ◽  
Tanja Beament ◽  
Michael Chance ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Natural Populations ◽  
Protozoan Parasite ◽  
West African ◽  
Acute Disease ◽  
East African ◽  
Content Type ◽  
Trypanosoma Brucei Gambiense ◽  
Acute Form ◽  
Genomic Introgression

ABSTRACT Human African trypanosomiasis is caused by two subspecies of Trypanosoma brucei. Trypanosoma brucei rhodesiense is found in East Africa and frequently causes acute disease, while Trypanosoma brucei gambiense is found in West Africa and is associated with chronic disease. Samples taken from a single focus of a Ugandan outbreak of T. b. rhodesiense in the 1980s were associated with either chronic or acute disease. We sequenced the whole genomes of two of these isolates, which showed that they are genetically distinct from each other. Analysis of single nucleotide polymorphism markers in a panel of 31 Ugandan isolates plus 32 controls revealed a mixture of East African and West African haplotypes, and some of these haplotypes were associated with the different virulence phenotypes. It has been shown recently that T. b. brucei and T. b. rhodesiense populations undergo genetic exchange in natural populations. Our analysis showed that these strains from the Ugandan epidemic were intermediate between the reference genome sequences of T. b. gambiense and T. b. brucei and contained haplotypes that were present in both subspecies. This suggests that the human-infective subspecies of T. brucei are not genetically isolated, and our data are consistent with genomic introgression between East African and West African T. b. brucei subspecies. This has implications for the control of the parasite, the spread of drug resistance, and understanding the variation in virulence and the emergence of human infectivity. IMPORTANCE We present a genetic study of the acute form of “sleeping sickness” caused by the protozoan parasite Trypanosoma brucei rhodesiense from a single outbreak in Uganda. This represents an advance in our understanding of the relationship between the T. b. rhodesiense and Trypanosoma brucei gambiense subspecies that have previously been considered geographically distinct. Our data suggest that introgression of West African-derived T. brucei haplotypes may be associated with differences in disease presentation in the East African disease. These findings are not only of scientific interest but also important for parasite control, as they suggest that the human-infective T. brucei subspecies are not genetically isolated.

scholarly journals Secondary contact seeds phenotypic novelty in cichlid fishes

2015 ◽  
Vol 282 (1798) ◽  
pp. 20142272 ◽  
Author(s):  
Paul Nichols ◽  
Martin J. Genner ◽  
Cock van Oosterhout ◽  
Alan Smith ◽  
Paul Parsons ◽  
...  
Keyword(s):  
Adaptive Evolution ◽  
Natural Populations ◽  
Cichlid Fish ◽  
Single Species ◽  
Secondary Contact ◽  
Isolated Populations ◽  
In The Wild ◽  
Genetic Novelty ◽  
Genomic Introgression ◽  
Phenotypic Novelty

Theory proposes that genomic admixture between formerly reproductively isolated populations can generate phenotypic novelty for selection to act upon. Secondary contact may therefore be a significant promoter of phenotypic novelty that allows species to overcome environmental challenges and adapt to novel environments, including during adaptive radiation. To date, this has largely been considered from the perspective of interspecific hybridization at contact zones. However, it is also possible that this process occurs more commonly between natural populations of a single species, and thus its importance in adaptive evolution may have been underestimated. In this study, we tested the consequences of genomic introgression during apparent secondary contact between phenotypically similar lineages of the riverine cichlid fish Astatotilapia calliptera . We provide population genetic evidence of a secondary contact zone in the wild, and then demonstrate using mate-choice experiments that both lineages can reproduce together successfully in laboratory conditions. Finally, we show that genomically admixed individuals display extreme phenotypes not observed in the parental lineages. Collectively, the evidence shows that secondary contact can drive the evolution of phenotypic novelty, suggesting that pulses of secondary contact may repeatedly seed genetic novelty, which when coupled with ecological opportunity could promote rapid adaptive evolution in natural circumstances.

Early-generation germplasm introgression from Sorghum macrospermum into sorghum (S. bicolor)

Genome ◽  
2010 ◽  
Vol 53 (6) ◽  
pp. 419-429 ◽  
Author(s):  
Les C. Kuhlman ◽  
Byron L. Burson ◽  
David M. Stelly ◽  
Patricia E. Klein ◽  
Robert R. Klein ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Cytogenetic Analysis ◽  
Seed Set ◽  
Embryo Rescue ◽  
Male Sterile ◽  
Breeding Programs ◽  
Public And Private ◽  
Molecular Cytogenetic ◽  
Improvement Programs ◽  
Genomic Introgression

Sorghum has been improved by public and private breeding programs utilizing germplasm mostly from within the species Sorghum bicolor . Recently, hybridization with an Australian species, S. macrospermum (AAB1B1YYZZ), has been demonstrated and the genomic relationship to S. bicolor (AAB1B1) shown to be partially compatible. For this species to be potentially useful to sorghum improvement programs, there must be documented introgression into an S. bicolor background. Fifteen BC1F1 progeny were recovered using the interspecific hybrid as a female and embryo rescue. In these progeny, chromosome numbers ranged from 35 to 70 and all were essentially male-sterile. Repeated backcrossing with S. bicolor pollen produced BC2F1 seed on 3 of the 15 BC1F1 plants. BC2F1 progeny had varying levels of male fertility; selfed seed set ranged from 0% to 95%, with only 2 individuals being completely male-sterile. Using AFLP and SSR markers, genomic introgression of S. macrospermum ranged from 0% to 18.6%. Cytogenetic analysis of 19 individuals revealed that chromosome numbers were 20, except for a single backcross that had 21 chromosomes. Molecular cytogenetic analysis confirmed the presence of recombinant introgression chromosomes as well as alien addition and alien substitution chromosomes within the BC2F1s.

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