Publikasjoner
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Bergman, Nora M.; Lehikoinen, Petteri; Kluen, Edward; Bensch, Staffan; Sætre, Camilla Lo Cascio & Eroukhmanoff, Fabrice Damien
[Vis alle 13 forfattere av denne artikkelen]
(2025).
Combined evidence reveals the origin of a rapid range expansion despite retained genetic diversity and a weak founder effect.
Molecular Ecology.
ISSN 0962-1083.
34(19).
doi:
10.1111/mec.70077.
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Many species are currently experiencing range shifts in response to changing environmental conditions with potentially serious genetic consequences. Repeated founder events and strong genetic drift are expected to erode genetic variation at the range front, reducing adaptive potential and slowing or even halting the expansion. However, the severity of these consequences for common and highly mobile species undergoing environment-driven range shifts (c.f. invasions) is less clear. Here, we combined historical observations and contemporary movement data of the common reed warbler (Acrocephalus scirpaceus) with genomic evidence from across its European breeding range to (1) infer the origin and (2) quantify the genetic consequences of a recent and rapid northward range expansion. Although there were no reductions in levels of nucleotide diversity or allelic richness, nor a signal of founder effect in the directionality index (ψ), our combined dataset approach was able to infer an expansion origin from the southwest. Furthermore, we found that private allelic richness retained a slight but significant linear decline along the colonisation route. These results suggest that high dispersal capabilities can allow even philopatric species to avoid the loss of genetic diversity during rapid range expansions. Nevertheless, if multiple lines of evidence enable identification of an expansion pathway, we may still detect genetic signals of expansion.
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Johnsen, Arild; Dobbe, Kristine; Sætre, Camilla Lo Cascio; Eybert, Marie-Christine; Marquet, Matthieu & Bonnet, Patrick
[Vis alle 7 forfattere av denne artikkelen]
(2023).
Genetic diversity and sperm characteristics are not associated in two bluethroat (Luscinia svecica) populations.
Journal of Avian Biology.
ISSN 0908-8857.
s. 1–9.
doi:
10.1111/jav.03125.
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Individual heterozygosity may influence the expression of fitness‐related traits, via genome‐wide or local genetic effects. Earlier studies have shown negative relationships between heterozygosity and sperm variation, predominantly in captive, highly inbred populations. Little is known about the possible influence of variation in heterozygosity on sperm traits in wild, outbred populations. We studied two populations of the bluethroat, one from the widely distributed northern subspecies Luscinia. s. svecica and the other from the smaller, more patchily distributed subspecies breeding along the French coast of Brittany L. s. namnetum . The two subspecies differed significantly in body size, plumage colour, sperm traits and the degree of genetic diversity. However, there was no evidence that sperm traits (total length and motility) were influenced by the degree of heterozygosity at the individual level. In contrast, we found that male body size was positively related to heterozygosity across both populations, indicating a possible relationship between overall genetic diversity and general vigour or ability to obtain food. We conclude that sperm traits are unrelated to levels of heterozygosity in the studied outbred and weakly genetically depauperate bluethroat populations.
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Sætre, Camilla Lo Cascio; Eroukhmanoff, Fabrice; Rönkä, Katja; Kluen, Edward; Thorogood, Rose & Torrance, James
[Vis alle 12 forfattere av denne artikkelen]
(2021).
A Chromosome-Level Genome Assembly of the Reed Warbler (Acrocephalus scirpaceus).
Genome Biology and Evolution (GBE).
13(9),
s. 1–7.
doi:
10.1093/gbe/evab212.
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Abstract The reed warbler (Acrocephalus scirpaceus) is a long-distance migrant passerine with a wide distribution across Eurasia. This species has fascinated researchers for decades, especially its role as host of a brood parasite, and its capacity for rapid phenotypic change in the face of climate change. Currently, it is expanding its range northwards in Europe, and is altering its migratory behavior in certain areas. Thus, there is great potential to discover signs of recent evolution and its impact on the genomic composition of the reed warbler. Here, we present a high-quality reference genome for the reed warbler, based on PacBio, 10×, and Hi-C sequencing. The genome has an assembly size of 1,075,083,815 bp with a scaffold N50 of 74,438,198 bp and a contig N50 of 12,742,779 bp. BUSCO analysis using aves_odb10 as a model showed that 95.7% of BUSCO genes were complete. We found unequivocal evidence of two separate macrochromosomal fusions in the reed warbler genome, in addition to the previously identified fusion between chromosome Z and a part of chromosome 4A in the Sylvioidea superfamily. We annotated 14,645 protein-coding genes, and a BUSCO analysis of the protein sequences indicated 97.5% completeness. This reference genome will serve as an important resource, and will provide new insights into the genomic effects of evolutionary drivers such as coevolution, range expansion, and adaptations to climate change, as well as chromosomal rearrangements in birds.
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Sætre, Camilla Lo Cascio; Johnsen, Arild; Stensrud, Even & Cramer, Emily Rebecca A
(2018).
Sperm morphology, sperm motility and paternity success in the bluethroat (Luscinia svecica).
PLOS ONE.
13(3).
doi:
10.1371/journal.pone.0192644.
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Postcopulatory sexual selection may select for male primary sexual characteristics like sperm morphology and sperm motility, through sperm competition or cryptic female choice. However, how such characteristics influence male fertilization success remains poorly understood. In this study, we investigate possible correlations between sperm characteristics and paternity success in the socially monogamous bluethroat (Luscinia svecica svecica), predicting that sperm length and sperm swimming speed is positively correlated with paternity success. In total, 25% (15/61) of broods contained extra-pair offspring and 10% (33/315) of the offspring were sired by extra-pair males. Paternity success did not correlate significantly with sperm morphology or any aspects of sperm motility. Furthermore, sperm morphology and sperm motility did not correlate significantly with male morphological characters that previously have been shown to be associated with paternity success. Thus, the sperm characteristics investigated here do not appear to be strong predictors of paternity success in bluethroats.
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Sætre, Glenn-Peter; Pulido, Angelica Maria Cuevas; Hermansen, Jo Skeie; Elgvin, Tore Oldeide; Fernández, Laura Piñeiro & Sæther, Stein Are
[Vis alle 8 forfattere av denne artikkelen]
(2017).
Rapid polygenic response to secondary contact in a hybrid species.
Proceedings of the Royal Society of London. Biological Sciences.
ISSN 0962-8452.
284(1853).
doi:
10.1098/rspb.2017.0365.
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Secondary contact between closely related species can have genetic consequences.
Competition for essential resources may lead to divergence in
heritable traits that reduces interspecific competition leading to increased rate of genetic divergence. Conversely, hybridization and backcrossing can lead to genetic convergence. Here, we study a population of a hybrid
species, the Italian sparrow (Passer italiae), before and after it came into secondary contact with one of its parent species, the Spanish sparrow (P. hispaniolensis), in 2013. We demonstrate strong consequences of interspecific
competition: Italian sparrows were kept away from a popular
feeding site by its parent species, resulting in poorer body condition and a significant drop in population size. Although no significant morphological change could be detected, after only 3 years of sympatry, the Italian sparrows had diverged significantly from the Spanish sparrows across a set of 81 protein-coding genes. These temporal genetic changes are mirrored by genetic divergence observed in older sympatric Italian sparrow populations
within the same area of contact. Compared with microallopatric birds, sympatric ones are genetically more diverged from Spanish sparrows. Six significant outlier genes in the temporal and spatial comparison (i.e. showing
the greatest displacement) have all been found to be associated with learning and neural development in other bird species.
character displacement, interspecific
competition, Passer, hybrid species,
cognition, learning
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Sætre, Camilla Lo Cascio; Coleiro, Charles; Austad, Martin; Gauci, Mark; Sætre, Glenn-Peter & Voje, Kjetil L.
[Vis alle 7 forfattere av denne artikkelen]
(2017).
Rapid adaptive phenotypic change following colonization of a newly restored habitat.
Nature Communications.
8(14159),
s. 1–6.
doi:
10.1038/ncomms14159.
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Real-time observation of adaptive evolution in the wild is rare and limited to cases of marked, often anthropogenic, environmental change. Here we present the case of a small population of reed warblers (Acrocephalus scirpaceus) over a period of 19 years (1996–2014) after colonizing a restored wetland habitat in Malta. Our data show a population decrease in body mass, following a trajectory consistent with a population ascending an adaptive peak, a so-called Ornstein–Uhlenbeck process. We corroborate these findings with genetic and ecological data, revealing that individual survival is correlated with body mass, and more than half of the variation in mean population fitness is explained by variation in body mass. Despite a small effective population size, an adaptive response has taken place within a decade. A founder event from a large, genetically variable source population to the southern range margin of the reed warbler distribution likely facilitated this process.
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Publisert
16. sep. 2016 10:22
