scholarly journals Local adaptation and sexual selection drive intra-island diversification in a songbird lineage: differential divergence in autosomes and sex chromosomes

2018 ◽  
Author(s):  
Yann XC Bourgeois ◽  
Joris AM Bertrand ◽  
Boris Delahaie ◽  
Hélène Holota ◽  
Christophe Thébaud ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Reproductive Isolation ◽  
Local Adaptation ◽  
Sex Chromosomes ◽  
Genomic Variation ◽  
Color Variation ◽  
Mating Signals ◽  
Genome Wide

AbstractRecently diverged taxa showing marked phenotypic and ecological diversity are optimal systems to test the relative importance of two major evolutionary mechanisms, adaptation to local ecological conditions by natural selection, or mechanisms of reproductive isolation such as assortative mating mediated by sexually selected mating signals or post-zygotic incompatibilities. Whereas local adaptation is expected to affect many loci throughout the genome, traits acting as mating signals are expected to be located on sex chromosomes and have a simple genetic basis. We used genome-wide markers to test these predictions in Reunion Island’s gray-white eye (Zosterops borbonicus), which has recently diversified into five distinct plumage forms. Two of them correspond to a polymorphic highland population that is separated by a steep ecological gradient from three distinct lowland forms that show narrow contact zones in plumage color traits, yet no association with environmental variables. An analysis of population structure using genome-wide SNP loci revealed two major clades corresponding to highland and lowland forms, respectively, with the latter separated further into three independent lineages corresponding to plumage forms. Coalescent tests of alternative demographic scenarios provided support for divergence of highland and lowland lineages with an intensification of gene flow in the last 60,000 years. Landscapes of genomic variation revealed that signatures of selection associated with elevation are found at multiple regions across the genome, whereas most loci associated with the lowland forms are located on the Z sex chromosome. A gene ontology analysis identified TYRP1, a Z-linked color gene, as a likely candidate locus underlying color variation among lowland forms. Our results are consistent with the role of natural selection in driving the divergence of locally adapted highland populations, and the role of sexual selection in differentiating lowland forms through reproductive isolation mechanisms, showing that both modes of lineage divergence can take place at very small geographic scales in birds.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

Adaptation

2012 ◽  
Author(s):  
Lee Cronk ◽  
Beth L. Leech
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Levels Of Explanation ◽  
Different Levels ◽  
Culture And Language ◽  
Evolutionary Explanations

This chapter examines the concept of adaptation and how it is applied (and sometimes misapplied) to cooperation. It starts with George C. Williams's idea that adaptation is a “special and onerous concept that should be used only where it is really necessary,” which he articulated in Adaptation and Natural Selection. It then considers different levels of explanation that help clarify the notion of adaptation, fortuitous benefits and by-product mutualism in relation to adaptation, and the link between adaptation and natural, artificial, social, and sexual selection. It also explores how phylogeny constrains natural selection, the ways that adaptations solve specific problems found in specific environments, and how adaptation influences judgment. Finally, it analyzes the role of culture and language in adaptation and evolutionary explanations of morality.

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 Sperm numbers vary between inter- and intra-population matings of the grasshopper Chorthippus parallelus

2006 ◽  
Vol 2 (2) ◽  
pp. 239-241 ◽  
Author(s):  
Klaus Reinhardt
Keyword(s):  
Sexual Selection ◽  
Reproductive Isolation ◽  
Reproductive Output ◽  
Mating Effort ◽  
Sperm Number ◽  
Storage Organ ◽  
Genetic Incompatibility ◽  
Chorthippus Parallelus ◽  
Mating Signals ◽  
Crucial Assumption

Comparing the reproductive output of intra- and inter-population matings is the most common way to assess whether post-mating reproductive isolation is caused by genetic incompatibilities. Such genetic incompatibility can however, only assume that the quantity of the post-mating signals involved does not differ between intra- and inter-population matings. This assumption may not be true because sexual selection predicts reduced mating effort towards low-quality mates and in many circumstances, allopatric partners are low-quality mates. Post-mating efforts may, therefore, be reduced in inter- compared to intra-population matings. Here, I test this crucial assumption by studying variation in one post-mating trait, sperm number, in crosses of two parapatric grasshopper populations. In both populations, males transferred fewer sperm to allopatric than sympatric females. If such plasticity with respect to population is common in other post-mating traits, differences between inter- and intra-population crosses may be more frequently caused by differences in sperm number rather than gamete incompatibility. Additionally, I found that sperm numbers declined less rapidly in the female storage organ of allopatric than sympatric females but its rate differed markedly between populations. This is discussed with respect to female adaptations to male traits.

Evolving Better Cars

2014 ◽  
Vol 76 (4) ◽  
pp. 259-264 ◽  
Author(s):  
Anne M. Royer ◽  
Elizabeth H. Schultheis
Keyword(s):  
Natural Selection ◽  
Local Adaptation ◽  
Computer Applications ◽  
Online Program ◽  
Virtual Population ◽  
Evolution By Natural Selection ◽  
Long Timescales ◽  
Independent Inquiry

Evolutionary experiments are usually difficult to perform in the classroom because of the large sizes and long timescales of experiments testing evolutionary hypotheses. Computer applications give students a window to observe evolution in action, allowing them to gain comfort with the process of natural selection and facilitating inquiry experimentation. The lesson described here uses a free online program, BoxCar2D, to demonstrate evolution by natural selection in a virtual population of cars. Students will be introduced to the principles of evolution and conduct independent inquiry projects on key predictions from evolution – including convergence, local adaptation, and the role of mutation in adaptation.

scholarly journals Genome-wide SNP genotyping highlights the role of natural selection in Plasmodium falciparumpopulation divergence

2008 ◽  
Vol 9 (12) ◽  
Author(s):  
Daniel E Neafsey ◽  
Stephen F Schaffner ◽  
Sarah K Volkman ◽  
Daniel Park ◽  
Philip Montgomery ◽  
...  
Keyword(s):  
Natural Selection ◽  
Snp Genotyping ◽  
Genome Wide

scholarly journals Translating “natural selection” in Japanese: from “shizen tōta” to “shizen sentaku”, and back?

Bionomina ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 26-48 ◽  
Author(s):  
Taizo KIJIMA ◽  
Thierry HOQUET
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Point Of View ◽  
The Other ◽  
First Finding ◽  
Restriction Policy ◽  
History Of ◽  
Japanese Translation ◽  
Over Time

This paper focuses on terminological issues related to the translation of Darwin’s concept of “natural selection” in Japanese. We analyze the historical fate of the different phrases used as translations, from the first attempts in the late 1870s until recent times. Our first finding is that the first part of the Japanese translations never changed during the period considered: “natural” was constantly rendered by “shizen”. By contrast, the Japanese terms for “selection” have dramatically changed over time. We identify some major breaks in the history of Japanese translations for “natural selection”. From the end of the 1870s to the early 1880s, several translations were suggested in books and periodicals: “shizen kanbatsu”, “shizen tōta”, “tensen”. Katō Hiroyuki adopted “shizen tōta” in 1882 and he undeniably played an important role in spreading this phrase as the standard translation for “natural selection”. The most common Japanese translation of the Origin during the first half of the 20th century (by Oka Asajirō in 1905) also used “shizen tōta”. Adramatic shift occurred after WWII, from “tōta” to “sentaku”. While a linear interpretation could suggest a move from a “bad” translation to a better one, a closer analysis leads to more challenging insights. Especially we stress the role of the kanji restriction policy, which specified which kanji should be taught in schools and thus should be used in textbooks: “tōta” was not included in the list, which may have led to the good fortune of “sentaku” in the 1950–1960s. We think the hypothesis of the influence of Chinese translations is not a plausible one. As to conceptual differences between “shizen tōta” and “sentaku”, they remain unconvincing as both terms could be interpreted as a positive or negative process: there is no clear reason to prefer one term over the other from the strict point of view of their meanings or etymology. Then, turning to the way terms are used, we compare translations of natural selection with translations of artificial or sexual selection. First we turn to the field of thremmatology (breeders): there, “tōta” (sometimes spelled in hiragana instead of kanji) often bore the meaning of culling; since 1917, breeders often used “sentaku” as a translation for “selection”. However, quite surprisingly, breeders used two different terms for selection as a practice (“senbatsu”), and “selection” as in “natural selection” (“shizen sentaku”). Finally, we compare possible translations for “sexual selection” and “matechoice”: here again, there are some good reasons to favour “tōta” over “sentaku” to avoid lexical confusion.

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 Genomic and functional gene studies suggest a key role of beta-carotene oxygenase 1 like (bco1l) gene in salmon flesh color

2019 ◽  
Author(s):  
Hanna Helgeland ◽  
Marte Sodeland ◽  
Nina Zoric ◽  
Jacob Seilø Torgersen ◽  
Fabian Grammes ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Beta Carotene ◽  
Color Variation ◽  
Flesh Color ◽  
Functional Studies ◽  
Genetic Components ◽  
Genome Wide ◽  
A Genome ◽  
Mrna And Protein Expression

AbstractRed coloration of muscle tissue (flesh) is a unique trait in several salmonid genera, including Atlantic salmon. The color results from dietary carotenoids deposited in the flesh, whereas the color intensity is affected both by diet and genetic components. Herein we report on a genome-wide association study (GWAS) to identify genetic variation underlying this trait. Two SNPs on ssa26 showed strong associations to the flesh color in salmon. Two genes known to be involved in carotenoid metabolism were located in this QTL-region: beta-carotene oxygenase 1 (bco1) and beta-carotene oxygenase 1 like (bco1l). To determine whether flesh color variation is caused by one, or both, of these genes, several functional studies were carried out including mRNA and protein expression in fish with red and pale flesh color. The catalytic abilities of these two genes were also tested with different carotenoids. Our results suggest bco1l to be the most likely gene to explain the flesh color variation observed in this population.

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