scholarly journals Limited intrinsic postzygotic reproductive isolation despite chromosomal rearrangements between closely related sympatric species of small ermine moths (Lepidoptera: Yponomeutidae)

2019 ◽  
Vol 128 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Katerina H Hora ◽  
František Marec ◽  
Peter Roessingh ◽  
Steph B J Menken
Keyword(s):  
Reproductive Isolation ◽  
Parental Species ◽  
Meiotic Chromosome ◽  
Chromosomal Rearrangements ◽  
Sympatric Species ◽  
Hybrid Fitness ◽  
New Host ◽  
Closely Related Species ◽  
Postzygotic Reproductive Isolation

Abstract In evolutionarily young species and sympatric host races of phytophagous insects, postzygotic incompatibility is often not yet fully developed, but reduced fitness of hybrids is thought to facilitate further divergence. However, empirical evidence supporting this hypothesis is limited. To assess the role of reduced hybrid fitness, we studied meiosis and fertility in hybrids of two closely related small ermine moths, Yponomeuta padella and Yponomeuta cagnagella, and determined the extent of intrinsic postzygotic reproductive isolation. We found extensive rearrangements between the karyotypes of the two species and irregularities in meiotic chromosome pairing in their hybrids. The fertility of reciprocal F1 and, surprisingly, also of backcrosses with both parental species was not significantly decreased compared with intraspecific offspring. The results indicate that intrinsic postzygotic reproductive isolation between these closely related species is limited. We conclude that the observed chromosomal rearrangements are probably not the result of an accumulation of postzygotic incompatibilities preventing hybridization. Alternative explanations, such as adaptation to new host plants, are discussed.

scholarly journals How Can Satellite DNA Divergence Cause Reproductive Isolation? Let Us Count the Chromosomal Ways

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick M. Ferree ◽  
Satyaki Prasad
Keyword(s):  
Reproductive Isolation ◽  
Developmental Stages ◽  
Rapid Evolution ◽  
Model Organisms ◽  
Cellular Mechanisms ◽  
Closely Related Species ◽  
Heterochromatin Formation ◽  
Interspecies Hybrids ◽  
Postzygotic Reproductive Isolation ◽  
And Function

Satellites are one of the most enigmatic parts of the eukaryotic genome. These highly repetitive, noncoding sequences make up as much as half or more of the genomic content and are known to play essential roles in chromosome segregation during meiosis and mitosis, yet they evolve rapidly between closely related species. Research over the last several decades has revealed that satellite divergence can serve as a formidable reproductive barrier between sibling species. Here we highlight several key studies on Drosophila and other model organisms demonstrating deleterious effects of satellites and their rapid evolution on the structure and function of chromosomes in interspecies hybrids. These studies demonstrate that satellites can impact chromosomes at a number of different developmental stages and through distinct cellular mechanisms, including heterochromatin formation. These findings have important implications for how loci that cause postzygotic reproductive isolation are viewed.

scholarly journals Multi-locus interactions and the build-up of reproductive isolation

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190543 ◽  
Author(s):  
I. Satokangas ◽  
S. H. Martin ◽  
H. Helanterä ◽  
J. Saramäki ◽  
J. Kulmuni
Keyword(s):  
Reproductive Isolation ◽  
Empirical Work ◽  
Hybrid Fitness ◽  
Epistatic Interactions ◽  
Genome Scans ◽  
Theoretical Approaches ◽  
Genome Wide ◽  
Experimental Approaches ◽  
Polymorphism Data

All genes interact with other genes, and their additive effects and epistatic interactions affect an organism's phenotype and fitness. Recent theoretical and empirical work has advanced our understanding of the role of multi-locus interactions in speciation. However, relating different models to one another and to empirical observations is challenging. This review focuses on multi-locus interactions that lead to reproductive isolation (RI) through reduced hybrid fitness. We first review theoretical approaches and show how recent work incorporating a mechanistic understanding of multi-locus interactions recapitulates earlier models, but also makes novel predictions concerning the build-up of RI. These include high variance in the build-up rate of RI among taxa, the emergence of strong incompatibilities producing localized barriers to introgression, and an effect of population size on the build-up of RI. We then review recent experimental approaches to detect multi-locus interactions underlying RI using genomic data. We argue that future studies would benefit from overlapping methods like ancestry disequilibrium scans, genome scans of differentiation and analyses of hybrid gene expression. Finally, we highlight a need for further overlap between theoretical and empirical work, and approaches that predict what kind of patterns multi-locus interactions resulting in incompatibilities will leave in genome-wide polymorphism data. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

scholarly journals Recurrent erosion of COA1/MITRAC15 demonstrates gene dispensability in oxidative phosphorylation

2021 ◽  
Author(s):  
Sagar Sharad Shinde ◽  
Sandhya Sharma ◽  
Lokdeep Teekas ◽  
Ashutosh Sharma ◽  
Nagarjun Vijay
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Gene Loss ◽  
Chromosomal Rearrangements ◽  
Genomic Region ◽  
Glycolytic Pathway ◽  
Mitochondrial Translation ◽  
Closely Related Species ◽  
Genome Assemblies

Skeletal muscle fibers rely upon either oxidative phosphorylation or glycolytic pathway to achieve muscular contractions that power mechanical movements. Species with energy-intensive adaptive traits that require sudden bursts of energy have a greater dependency on fibers that use the glycolytic pathway. Glycolytic fibers have decreased reliance on OXPHOS and lower mitochondrial content compared to oxidative fibers. Hence, we hypothesized that adaptive gene loss might have occurred within the OXPHOS pathway in lineages that largely depend on glycolytic fibers. The protein encoded by the COA1/MITRAC15 gene with conserved orthologs found in budding yeast to humans promotes mitochondrial translation. We show that gene disrupting mutations have accumulated within the COA1/MITRAC15 gene in the cheetah, several species of galliforms, and rodents. The genomic region containing COA1/MITRAC15 is a well-established evolutionary breakpoint region in mammals. Careful inspection of genome assemblies of closely related species of rodents and marsupials suggests two independent COA1/MITRAC15 gene loss events co-occurring with chromosomal rearrangements. Besides recurrent gene loss events, we document changes in COA1/MITRAC15 exon structure in primates and felids. The detailed evolutionary history presented in this study reveals the intricate link between skeletal muscle fiber composition and dispensability of the chaperone-like role of the COA1/MITRAC15 gene.

scholarly journals Population genomic evidence of selection on structural variants in a natural hybrid zone

2022 ◽  
Author(s):  
Linyi Zhang ◽  
Samridhi Chaturvedi ◽  
Chris Nice ◽  
Lauren Lucas ◽  
Zachariah Gompert
Keyword(s):  
Reproductive Isolation ◽  
Hybrid Zone ◽  
Structural Variants ◽  
Hybrid Fitness ◽  
Genome Wide ◽  
Oxford Nanopore ◽  
Jackson Hole ◽  
Long Read ◽  
Genomic Regions

Structural variants (SVs) can promote speciation by directly causing reproductive isolation or by suppressing recombination across large genomic regions. Whereas examples of each mechanism have been documented, systematic tests of the role of SVs in speciation are lacking. Here, we take advantage of long-read (Oxford nanopore) whole-genome sequencing and a hybrid zone between two Lycaeides butterfly taxa (L. melissa and Jackson Hole Lycaeides) to comprehensively evaluate genome-wide patterns of introgression for SVs and relate these patterns to hypotheses about speciation. We found >100,000 SVs segregating within or between the two hybridizing species. SVs and SNPs exhibited similar levels of genetic differentiation between species, with the exception of inversions, which were more differentiated. We detected credible variation in patterns of introgression among SV loci in the hybrid zone, with 562 of 1419 ancestry-informative SVs exhibiting genomic clines that deviating from null expectations based on genome-average ancestry. Overall, hybrids exhibited a directional shift towards Jackson Hole Lycaeides ancestry at SV loci, consistent with the hypothesis that these loci experienced more selection on average then SNP loci. Surprisingly, we found that deletions, rather than inversions, showed the highest skew towards excess introgression from Jackson Hole Lycaeides. Excess Jackson Hole Lycaeides ancestry in hybrids was also especially pronounced for Z-linked SVs and inversions containing many genes. In conclusion, our results show that SVs are ubiquitous and suggest that SVs in general, but especially deletions, might contribute disproportionately to hybrid fitness and thus (partial) reproductive isolation.

scholarly journals Recurrent erosion of COA1/MITRAC15 exemplifies conditional gene dispensability in oxidative phosphorylation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sagar Sharad Shinde ◽  
Sandhya Sharma ◽  
Lokdeep Teekas ◽  
Ashutosh Sharma ◽  
Nagarjun Vijay
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Gene Loss ◽  
Chromosomal Rearrangements ◽  
Genomic Region ◽  
Mitochondrial Translation ◽  
Closely Related Species ◽  
Genome Assemblies ◽  
Exon Structure

AbstractSkeletal muscle fibers rely upon either oxidative phosphorylation or the glycolytic pathway with much less reliance on oxidative phosphorylation to achieve muscular contractions that power mechanical movements. Species with energy-intensive adaptive traits that require sudden bursts of energy have a greater dependency on glycolytic fibers. Glycolytic fibers have decreased reliance on OXPHOS and lower mitochondrial content compared to oxidative fibers. Hence, we hypothesized that gene loss might have occurred within the OXPHOS pathway in lineages that largely depend on glycolytic fibers. The protein encoded by the COA1/MITRAC15 gene with conserved orthologs found in budding yeast to humans promotes mitochondrial translation. We show that gene disrupting mutations have accumulated within the COA1 gene in the cheetah, several species of galliform birds, and rodents. The genomic region containing COA1 is a well-established evolutionary breakpoint region in mammals. Careful inspection of genome assemblies of closely related species of rodents and marsupials suggests two independent COA1 gene loss events co-occurring with chromosomal rearrangements. Besides recurrent gene loss events, we document changes in COA1 exon structure in primates and felids. The detailed evolutionary history presented in this study reveals the intricate link between skeletal muscle fiber composition and the occasional dispensability of the chaperone-like role of the COA1 gene.

scholarly journals Species integrity enhanced by a predation cost to hybrids in the wild

2017 ◽  
Vol 13 (7) ◽  
pp. 20170208 ◽  
Author(s):  
P. Anders Nilsson ◽  
Kaj Hulthén ◽  
Ben B. Chapman ◽  
Lars-Anders Hansson ◽  
Jakob Brodersen ◽  
...  
Keyword(s):  
Related Species ◽  
Parental Species ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Hybrid Fitness ◽  
Closely Related Species ◽  
Ecological Selection ◽  
Field Evidence ◽  
In The Wild ◽  
Species Integrity

Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama ) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo ). Scanning for regurgitated tags under cormorant roosts 3–4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.

scholarly journals Reproductive isolation in a nascent species pair is associated with aneuploidy in hybrid offspring

2015 ◽  
Vol 282 (1802) ◽  
pp. 20142862 ◽  
Author(s):  
Anne-Marie Dion-Côté ◽  
Radka Symonová ◽  
Petr Ráb ◽  
Louis Bernatchez
Keyword(s):  
Reproductive Isolation ◽  
Chromosome Numbers ◽  
Chromosomal Instability ◽  
Diploid Number ◽  
Chromosomal Rearrangements ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Mitotic Instability ◽  
Two Populations

Speciation may occur when the genomes of two populations accumulate genetic incompatibilities and/or chromosomal rearrangements that prevent inter-breeding in nature. Chromosome stability is critical for survival and faithful transmission of the genome, and hybridization can compromise this. However, the role of chromosomal stability on hybrid incompatibilities has rarely been tested in recently diverged populations. Here, we test for chromosomal instability in hybrids between nascent species, the ‘dwarf’ and ‘normal’ lake whitefish ( Coregonus clupeaformis ). We examined chromosomes in pure embryos, and healthy and malformed backcross embryos. While pure individuals displayed chromosome numbers corresponding to the expected diploid number (2 n = 80), healthy backcrosses showed evidence of mitotic instability through an increased variance of chromosome numbers within an individual. In malformed backcrosses, extensive aneuploidy corresponding to multiples of the haploid number (1 n = 40, 2 n = 80, 3 n = 120) was found, suggesting meiotic breakdown in their F 1 parent. However, no detectable chromosome rearrangements between parental forms were identified. Genomic instability through aneuploidy thus appears to contribute to reproductive isolation between dwarf and normal lake whitefish, despite their very recent divergence (approx. 15–20 000 generations). Our data suggest that genetic incompatibilities may accumulate early during speciation and limit hybridization between nascent species.

scholarly journals Genetic architecture of a key reproductive isolation trait differs between sympatric and non-sympatric sister species of Lake Victoria cichlids

2020 ◽  
Vol 287 (1924) ◽  
pp. 20200270
Author(s):  
Anna F. Feller ◽  
Marcel P. Haesler ◽  
Catherine L. Peichel ◽  
Ole Seehausen
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Related Species ◽  
Genetic Architecture ◽  
Lake Victoria ◽  
Sympatric Species ◽  
Sister Species ◽  
Species Pair ◽  
Closely Related Species ◽  
Nuptial Coloration

One hallmark of the East African cichlid radiations is the rapid evolution of reproductive isolation that is robust to full sympatry of many closely related species. Theory predicts that species persistence and speciation in sympatry with gene flow are facilitated if loci of large effect or physical linkage (or pleiotropy) underlie traits involved in reproductive isolation. Here, we investigate the genetic architecture of a key trait involved in behavioural isolation, male nuptial coloration, by crossing two sister species pairs of Lake Victoria cichlids of the genus Pundamilia and mapping nuptial coloration in the F2 hybrids. One is a young sympatric species pair, representative of an axis of colour motif differentiation, red-dorsum versus blue, that is highly recurrent in closely related sympatric species. The other is a species pair representative of colour motifs, red-chest versus blue, that are common in allopatric but uncommon in sympatric closely related species. We find significant quantitative trait loci (QTLs) with moderate to large effects (some overlapping) for red and yellow in the sympatric red-dorsum × blue cross, whereas we find no significant QTLs in the non-sympatric red-chest × blue cross. These findings are consistent with theory predicting that large effect loci or linkage/pleiotropy underlying mating trait differentiation could facilitate speciation and species persistence with gene flow in sympatry.

Hybrid Songbirds are Deficient in Learning and Memory

2017 ◽  
Author(s):  
Michael A. McQuillan ◽  
Timothy C. Roth ◽  
Alex V. Huynh ◽  
Amber M. Rice
Keyword(s):  
Reproductive Isolation ◽  
Learning And Memory ◽  
Parental Species ◽  
Spatial Task ◽  
Poecile Atricapillus ◽  
Scatter Hoarding ◽  
Memory Ability ◽  
Poecile Carolinensis ◽  
Naturally Occurring ◽  
Postzygotic Reproductive Isolation

AbstractIdentifying the phenotypes underlying postzygotic reproductive isolation is crucial for fully understanding the evolution and maintenance of species. One potential postzygotic isolating barrier that has not yet been examined is learning and memory ability in hybrids. Learning and memory are important fitness-related traits, especially in scatter-hoarding species, where accurate retrieval of hoarded food is vital for winter survival. Here, we test the hypothesis that learning and memory ability can act as a postzygotic isolating barrier by comparing these traits among two scatter-hoarding songbird species, black-capped (Poecile atricapillus), Carolina chickadees (Poecile carolinensis), and their naturally occurring hybrids. In an outdoor aviary setting, we find that hybrid chickadees perform significantly worse on an associative learning spatial task and are worse at solving a novel problem compared to both parental species. Deficiencies in learning and memory abilities could therefore contribute to postzygotic reproductive isolation between chickadee species. Given the importance of learning and memory for fitness, our results suggest that these traits may play an important, but as yet overlooked, role in postzygotic reproductive isolation.

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