| 1. |
- Birkeland, Siri, et al.
(author)
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What can cold-induced transcriptomes of Arctic Brassicaceae tell us about the evolution of cold tolerance?
- 2022
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In: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:16, s. 4271-4285
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Journal article (peer-reviewed)abstract
- Little is known about the evolution of cold tolerance in polar plant species and how they differ from temperate relatives. To gain insight into their biology and the evolution of cold tolerance, we compared the molecular basis of cold response in three Arctic Brassicaceae species. We conducted a comparative time series experiment to examine transcriptional responses to low temperature. RNA was sampled at 22°C, and after 3, 6, and 24 at 2°C. We then identified sets of genes that were differentially expressed in response to cold and compared them between species, as well as to published data from the temperate Arabidopsis thaliana. Most differentially expressed genes were species-specific, but a significant portion of the cold response was also shared among species. Among thousands of differentially expressed genes, ~200 were shared among the three Arctic species and A. thaliana, while ~100 were exclusively shared among the three Arctic species. Our results show that cold response differs markedly between Arctic Brassicaceae species, but probably builds on a conserved basis found across the family. They also confirm that highly polygenic traits such as cold tolerance may show little repeatability in their patterns of adaptation.
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| 2. |
- Cerca, Jose, et al.
(author)
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The genomic basis of the plant island syndrome in Darwin's giant daisies
- 2022
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Journal article (peer-reviewed)abstract
- Many island plant species share a syndrome of characteristic phenotype and life history. Cerca et al. find the genomic basis of the plant island syndrome in one of Darwin's giant daisies, while separating ancestral genomes in a chromosome-resolved polyploid assembly. The repeated, rapid and often pronounced patterns of evolutionary divergence observed in insular plants, or the 'plant island syndrome', include changes in leaf phenotypes, growth, as well as the acquisition of a perennial lifestyle. Here, we sequence and describe the genome of the critically endangered, Galapagos-endemic species Scalesia atractyloides Arnot., obtaining a chromosome-resolved, 3.2-Gbp assembly containing 43,093 candidate gene models. Using a combination of fossil transposable elements, k-mer spectra analyses and orthologue assignment, we identify the two ancestral genomes, and date their divergence and the polyploidization event, concluding that the ancestor of all extant Scalesia species was an allotetraploid. There are a comparable number of genes and transposable elements across the two subgenomes, and while their synteny has been mostly conserved, we find multiple inversions that may have facilitated adaptation. We identify clear signatures of selection across genes associated with vascular development, growth, adaptation to salinity and flowering time, thus finding compelling evidence for a genomic basis of the island syndrome in one of Darwin's giant daisies.
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| 3. |
- Nowak, Michael D., et al.
(author)
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The genome of Draba nivalis shows signatures of adaptation to the extreme environmental stresses of the Arctic
- 2021
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In: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; :3, s. 661-676
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Journal article (peer-reviewed)abstract
- The Arctic is one of the most extreme terrestrial environments on the planet. Here, we present the first chromosome-scale genome assembly of a plant adapted to the high Arctic, Draba nivalis (Brassicaceae), an attractive model species for studying plant adaptation to the stresses imposed by this harsh environment. We used an iterative scaffolding strategy with data from short-reads, single-molecule long reads, proximity ligation data, and a genetic map to produce a 302 Mb assembly that is highly contiguous with 91.6% assembled into eight chromosomes (the base chromosome number). To identify candidate genes and gene families that may have facilitated adaptation to Arctic environmental stresses, we performed comparative genomic analyses with nine non-Arctic Brassicaceae species. We show that the D. nivalis genome contains expanded suites of genes associated with drought and cold stress (e.g., related to the maintenance of oxidation-reduction homeostasis, meiosis, and signaling pathways). The expansions of gene families associated with these functions appear to be driven in part by the activity of transposable elements. Tests of positive selection identify suites of candidate genes associated with meiosis and photoperiodism, as well as cold, drought, and oxidative stress responses. Our results reveal a multifaceted landscape of stress adaptation in the D. nivalis genome, offering avenues for the continued development of this species as an Arctic model plant.
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| 4. |
- Thoresen, Siri, et al.
(author)
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Long-term mental health and social support in victims of disaster : Comparison with a general population sample
- 2019
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In: BJPsych Open. - : Royal College of Psychiatrists. - 2056-4724. ; 5:1, s. 1-6
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Journal article (peer-reviewed)abstract
- BackgroundTrauma and traumatic bereavement have well-known consequences for mental health, but little is known about long-term adjustment, particularly with respect to health-protective factors.AimsTo assess the levels of anxiety/depression and perceived social support among the survivors and the bereaved 26 years after the Scandinavian Star ferry disaster compared with expected levels from the general population.MethodAnxiety/depression and social support were assessed in face-to-face interviews with the survivors and the bereaved (N = 165, response rate 58%). Expected scores were calculated for each participant based on the means and proportions for each age and gender combination from a general population sample. We computed the ratio between expected and observed scores, standardised mean differences with 95% confidence intervals and standardised effect sizes.ResultsWe found an elevated level of anxiety/depression symptoms in the victims (Mdiff = 0.28, 95% CI 0.18, 0.38; effect size 0.43, 95% CI 0.31, 0.55) and a significant excess of individuals with a clinically significant level of symptoms. The observed level of perceived social support was significantly lower than that expected (Mdiff = −0.57, 95% CI −0.70, −0.44; effect size −0.73, 95% CI −0.89, −0.57). This was the case for both survivors and those who were bereaved and for both men and women.ConclusionsThis study reveals that disaster survivors and the bereaved reported elevated levels of anxiety and depression symptoms 26 years after the event. They also reported a markedly reduced level of social support. Traumas and post-traumatic responses may thus cause lasting harm to interpersonal relationships.
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| 5. |
- Thoresen, Siri, et al.
(author)
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Scandinavian Star : Erfaringer og helse hos overlevende og etterlatte etter 26 år
- 2017
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Reports (other academic/artistic)abstract
- BackgroundScandinavian Star was a car and passenger ferry on route between Oslo, Norway and Frederikshavn, Denmark. During the night of April 7th, 1990, a fire broke out, which resulted in the death of 159 people. The police investigation concluded that the ship was set on fire by one or more arsonists. To date, the fire remains an unsolved crime. The aftermath has been ridden by controversies, and the ship owners and Norwegian authorities have been criticized.In 2015, The Norwegian Parliament appointed an independent commission with the mandate to evaluate several aspects of the Scandinavian Star case. As part of their work, the commission gave the Norwegian Centre for Violence and Traumatic Stress Studies the assignment to perform a systematic investigation of the survivors and the bereaved, focusing on traumatic exposure, what types of assistance they had received and their evaluation of this assistance, as well as current health, work participation, and well-being.The direct victims of this tragedy, both the survivors from the ship and the bereaved families, were involved in an extremely traumatic event. Exposure to adverse and traumatic events increases the risk for later health problems. In this report, we will describe the experiences of the survivors and the bereaved, with a focus on their recollection of what happened during the event, how they have perceived the support from the public health care system, what their own situation was like following the disaster, and their views on the political aftermath. We have also investigated health consequences as well as factors associated with current health.MethodsInformation letters with a description of the study and an invitation to participate were sent to the survivors and the bereaved. We performed face-to-face interviews during the autumn of 2016, 26 years after the fire. The survivors included both passengers and employees at the ship. Some survivors also lost someone they knew in the fire. The bereaved included individuals who were not present on the ship, but who lost someone close. In total, 193 individuals participated in the study, including 98 survivors and 95 bereaved, resulting in a response rate of 60% for both groups.ResultsExposureMany of the 98 survivors were exposed to danger during the fire. Three out of four survivors reported that they had been in areas of the ship with heavy smoke, and about half had experienced dangerous situations in the lifeboats. One out of five thought they were going to die. More than one third heard cries for help or saw someone seriously injured or killed. One in four survivors lost someone they knew to the fire.Among the 95 bereaved participants, who were not on board the ship, 81 had lost a close family member: a spouse, one or several children, one or both parents, or siblings. The majority lost more than one close person to the fire. About one out of four bereaved participants also had surviving relatives or friends on board the ship.Memories and centralityParticipants’ memories of this event were experienced as vivid and many could easily re-experience what happened.For many participants the fire had become highly central to their life story. The fire was also central for their understanding of the world and their personal identity. For example, one out of four survivors and more than half of the bereaved “fully agreed” that the fire changed their life forever.The aftermathLooking back to the first two years following the event, four out of ten reported that they had mental health problems and one out of four that they had somatic problems related to the fire. Almost half had accompanying difficulties with their daily life level of functioning. Among those who reported impaired functioning, one in four perceived that they never had regained their pre-fire level of functioning.The majority of the participants reported a lack of trust in the police investigations, and felt that the Norwegian authorities had shown little interest or support for those affected by the fire. Most participants reported satisfaction with the support they had received from their local communities.The general trust in the police and the justice system was significantly lower in the participants, compared to a general population sample. Trust in the police and the justice system was associated with the degree of trust in the authorities’ handling of the Scandinavian Star tragedy, and was also related to current mental health and perceived social support.Shame and guiltAbout one out of four reported that they had been worried about what others might think about them, and that they have had bothersome thoughts that they should have done something differently when it happened or to prevent it from happening.Support systemsOverall, negative opinions about the support were more prevalent than positive ones. The majority did not receive assistance without requesting it themselves, and they did not feel that they were taken good care of. About half felt they were not given sufficient time to talk with professionals.The most positive evaluations concerned the arrangement of a commemoration trip to Copenhagen and the Scandinavian Star Support group’s outreach program.Concerning the overall experience with the public health andsupport systems, negative evaluations were predominant among participants. More than half considered the support and treatment not at all or hardly satisfactory.One in three reported that they missed proactive outreach. Many participants underlined the need for long-term follow-up as well as assistance to children or support in parental roles.Work absence and current level of functioningAbout half of the participants reported to have had at least one lengthy absence from work during the years following the fire. Many participants attributed this absence to the consequences of the fire.About one in four had minor or major problems with their current level of daily functioning, which they attributed to the consequences of the fire.The participants’ self-rated mental health trajectoriesWhen looking back, participants reported to have had a low level of mental health problems in the period preceding the fire, which had increased dramatically at one month after the fire. From that time, the participants described a gradual process of recovery. Bereaved described a slower improvement compared to survivors. The current level of mental health problems remained higher than the low level reported before the fire.The participants’ evaluation of long-term mental health problems related to the fireMore than one third of the survivors, and almost half of the bereaved, reported that the fire had resulted in long-term mental health problems.Current health and life satisfactionMore than one out of four scored above a clinical cutoff for either posttraumatic stress reactions or anxiety/depression.One in five bereaved reported a current impairment in social, occupational or other important areas of functioning due to grief reactions. Only a few fulfilled the criteria for complicated grief.Participants had an increased level of anxiety/depression, and a lower level of social support, compared to a general population sample.About half of the participants had a high level of life satisfaction, yet one in five had a low or very low life satisfaction.Factors associated with mental and physical healthSocial support and barriers to social support were strongly associated with current mental and physical health. That is, individuals with a high level of perceived social support, and low barriers to seeking social support, had less mental and somatic health problems.Shame and guilt feelings related to what had happened, as well as centrality of the event, were also associated with current mental health.Conclusions and implications26 years after the disaster, the majority of survivors and bereaved had good health and a high level of life satisfaction. However, for many, the fire has had severe consequences. Even today, the affected group shows a disproportional burden of psychological health problems. Social factors, such as high perceived social support and a low level of social support barriers, seemed to be of particular importance for current mental health.The lack of confidence in the Norwegian authorities’ handling of the disaster might have contributed to a reduced general trust in the police and the justice system. This low level of trust was associated with impaired mental health and social relationships.Negative experiences or views regarding the early support and later treatment were predominant. Proactive outreach services are necessary post disaster, and these should last longer than has previously been assumed. Because social factors are of importance for mental health, interventions should target social relationships. For outreach services to be useful, specialized mental health care must be available when needed.Time does not heal all wounds. Despite all the years that have passed, many participants still remembered the event as if it happened yesterday. After a while, there is often an expectation that life should move on. But for some, life will never be the same, and it will take time to adjust to a new reality.
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