Chromosomal rearrangements can lead to the coupling of reproductive barriers, but whether and how they contribute to the completion of speciation remains unclear. Marine snails of the genus repeatedly form hybrid zones between populations segregating for multiple inversion arrangements, providing opportunities to study their barrier effects. Here, we analyzed 2 adjacent transects across hybrid zones between 2 ecotypes of ("large" and "dwarf") adapted to different wave exposure conditions on a Swedish island.
View Article and Find Full Text PDFSpecies within nearly all extant animal lineages are capable of regenerating body parts. However, it remains unclear whether the gene expression programme controlling regeneration is evolutionarily conserved. Brittle stars are a species-rich class of echinoderms with outstanding regenerative abilities, but investigations into the genetic bases of regeneration in this group have been hindered by the limited genomic resources.
View Article and Find Full Text PDFThe intertidal gastropod Littorina saxatilis is a model system to study speciation and local adaptation. The repeated occurrence of distinct ecotypes showing different levels of genetic divergence makes L. saxatilis particularly suited to study different stages of the speciation continuum in the same lineage.
View Article and Find Full Text PDFSpeciation is a key evolutionary process that is not yet fully understood. Combining population genomic and ecological data from multiple diverging pairs of marine snails (Littorina) supports the search for speciation mechanisms. Placing pairs on a one-dimensional speciation continuum, from undifferentiated populations to species, obscured the complexity of speciation.
View Article and Find Full Text PDFKey innovations are fundamental to biological diversification, but their genetic basis is poorly understood. A recent transition from egg-laying to live-bearing in marine snails ( spp.) provides the opportunity to study the genetic architecture of an innovation that has evolved repeatedly across animals.
View Article and Find Full Text PDFPhytoplankton have short generation times, flexible reproduction strategies, large population sizes and high standing genetic diversity, traits that should facilitate rapid evolution under directional selection. We quantified local adaptation of copper tolerance in a population of the diatom Skeletonema marinoi from a mining-exposed inlet in the Baltic Sea and in a non-exposed population 100 km away. We hypothesized that mining pollution has driven evolution of elevated copper tolerance in the impacted population of S.
View Article and Find Full Text PDFAllozymes present several classical examples of divergent selection, including the variation in the cytosolic aspartate aminotransferase (AAT) in the intertidal snails Littorina saxatilis. AAT is a part of the asparate-malate shuttle, in the interidal molluscs involved in the anaerobic respiration during desiccation. Previous allozyme studies reported the sharp gradient in the frequencies of the AATand the AAT alleles between the low and high shores in the Northern Europe and the differences in their enzymatic activity, supporting the role of AAT in adaptation to desiccation.
View Article and Find Full Text PDFWhy species that in their core areas mainly reproduce sexually become enriched with clones in marginal populations ("geographic parthenogenesis") remains unclear. Earlier hypotheses have emphasized that selection might promote clonality because it protects locally adapted genotypes. On the other hand, it also hampers recombination and adaptation to changing conditions.
View Article and Find Full Text PDFBackground: The four-item Patient Health Questionnaire-4 (PHQ-4) is a widely used screening measure for depression and anxiety.
Objectives: This study aimed to test factor structure and measurement invariance in an adult sample of the general population across seven European countries.
Method: A total sample of 9230 adults, 71.
Sandy beaches are biogeochemical hotspots that bridge marine and terrestrial ecosystems via the transfer of organic matter, such as seaweed (termed wrack). A keystone of this unique ecosystem is the microbial community, which helps to degrade wrack and re-mineralize nutrients. However, little is known about this community.
View Article and Find Full Text PDFUnderstanding the genetic targets of natural selection is one of the most challenging goals of population genetics. Some of the earliest candidate genes were identified from associations between allozyme allele frequencies and environmental variation. One such example is the clinal polymorphism in the arginine kinase () gene in the marine snail .
View Article and Find Full Text PDFMarine microorganisms have the potential to disperse widely with few obvious barriers to gene flow. However, among microalgae, several studies have demonstrated that species can be highly genetically structured with limited gene flow among populations, despite hydrographic connectivity. Ecological differentiation and local adaptation have been suggested as drivers of such population structure.
View Article and Find Full Text PDFUnderstanding population divergence that eventually leads to speciation is essential for evolutionary biology. High species diversity in the sea was regarded as a paradox when strict allopatry was considered necessary for most speciation events because geographical barriers seemed largely absent in the sea, and many marine species have high dispersal capacities. Combining genome-wide data with demographic modelling to infer the demographic history of divergence has introduced new ways to address this classical issue.
View Article and Find Full Text PDFThe Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10-year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three-day meetings and four conferences.
View Article and Find Full Text PDFSexual antagonism is a common hypothesis for driving the evolution of sex chromosomes, whereby recombination suppression is favored between sexually antagonistic loci and the sex-determining locus to maintain beneficial combinations of alleles. This results in the formation of a sex-determining region. Chromosomal inversions may contribute to recombination suppression but their precise role in sex chromosome evolution remains unclear.
View Article and Find Full Text PDFChromosomal inversions have been shown to play a major role in a local adaptation by suppressing recombination between alternative arrangements and maintaining beneficial allele combinations. However, so far, their importance relative to the remaining genome remains largely unknown. Understanding the genetic architecture of adaptation requires better estimates of how loci of different effect sizes contribute to phenotypic variation.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
April 2022
Understanding where, when and how species' ranges will be modified is both a fundamental problem and essential to predicting how spatio-temporal environmental changes in abiotic and biotic factors impact biodiversity. Notably, different species may respond disparately to similar environmental changes: some species may overcome an environmental change only with difficulty or not at all, while other species may readily overcome the same change. Ranges may contract, expand or move.
View Article and Find Full Text PDFBackground: Knowledge of what is uplifting and helpful during pandemics could inform the design of sustainable pandemic recommendations in the future. We have explored individuals' views on helpful and uplifting aspects of everyday life during the coronavirus disease 2019 (COVID-19) pandemic.
Methods: Participants answered a brief, daily survey via text messages during 14 consecutive days in July-August, 2020.
Inversions often underlie complex adaptive traits, but the genic targets inside them are largely unknown. Gene expression profiling provides a powerful way to link inversions with their phenotypic consequences. We examined the effects of the inversion in the seaweed fly on gene expression variation across sexes and life stages.
View Article and Find Full Text PDFChromosomal inversions have long been recognized for their role in local adaptation. By suppressing recombination in heterozygous individuals, they can maintain coadapted gene complexes and protect them from homogenizing effects of gene flow. However, to fully understand their importance for local adaptation we need to know their influence on phenotypes under divergent selection.
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