| 1. |
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| 2. |
- Graham, Jinko, et al.
(författare)
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Negative association between type 1 diabetes and HLA DQB1*0602-DQA1*0102 is attenuated with age at onset
- 1999
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Ingår i: European Journal of Immunogenetics. - : Wiley. - 0960-7420 .- 1365-2370. ; 26, s. 117-
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Tidskriftsartikel (refereegranskat)abstract
- HLA-associated relative risks of type 1 (insulin-dependent) diabetes mellitus were analysed in population-based Swedish patients and controls aged 0-34 years. The age dependence of HLA-associated relative risks was assessed by likelihood ratio tests of regression parameters in separate logistic regression models for each HLA category. The analyses demonstrated an attenuation with increasing age at onset in the relative risk for the positively associated DQB1*0201-A1*0502/B1*0302-A1*0301 (DQ2/8) genotype (P = 0.02) and the negatively associated DQB1*0602-A1*0102 (DQ6.2) haplotype (P = 0.004). At birth, DQ6.2-positive individuals had an estimated relative risk of 0.03, but this increased to 1.1 at age 35 years. Relative risks for individuals with DQ genotype 8/8 or 8/X or DQ genotype 2/2 or 2/X, where X is any DQ haplotype ether than 2, 8 or 6.2, were not significantly age-dependent. An exploratory analysis of DQ haplotypes other than 2, 8 and 6.2 suggested that the risk of type 1 diabetes increases with age for DQB1*0604-A1*0102 (DQ6.4) and that the peak risk for the negatively associated DQB1*0301-A1*0501 haplotype is at age 18 years. There was also weak evidence that the risk for DQB1*0303-A1*0301 (DQ9), which has a positive association in the Japanese population, may decrease with age. We speculate that HLA-DQ alleles have a significant effect on the rate of beta cell destruction, which is accelerated in DQ2/8-positive individuals and inhibited, but not completely blocked, in DQ6.2-positive individuals.
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| 3. |
- Henricsson, Marianne, et al.
(författare)
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The incidence of retinopathy 10 years after diagnosis in young adult people with diabetes: results from the nationwide population-based Diabetes Incidence Study in Sweden (DISS).
- 2003
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Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 26:2, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—To estimate the prevalence and severity of diabetic retinopathy (DR) 10 years after diagnosis in a nationwide population-based cohort study of young adult diabetic patients in Sweden. RESEARCH DESIGN AND METHODS—The Diabetes Incidence Study in Sweden (DISS) aims to register all incident cases of diabetes aged 15–34 years in Sweden. In 1987–1988, 806 cases were reported, and 627 (78%) of them were followed up with regard to retinopathy 8–10 years later. The assessment was based on retinal photographs in most cases (86%). RESULTS—Ten years after diagnosis, retinopathy was found in 247 patients (39%). The retinopathy was mild in 206 (33%), whereas 30 (4.8%) patients had moderate nonproliferative DR (NPDR) and 11 (1.8%) had proliferative DR (PDR). Patients with retinopathy had worse glycemic control during the years than patients without (HbA1c 8.1 ± 1.5% and 6.8 ± 1.2%, respectively; P < 0.001). In a Cox regression analysis, time to retinopathy was related to high HbA1c (P < 0.001) and high BMI (P = 0.001). Patients with type 2 diabetes had an increased prevalence of severe retinopathy (NPDR or PDR) compared with those with type 1 diabetes (14 of 93 [15%] versus no or mild 24 of 471 [5%], respectively; P < 0.001). CONCLUSIONS—Despite modern diabetes management, 39% of young adult diabetic patients developed retinopathy within the first 10 years of the disease. Nevertheless, compared with the prevalence of retinopathy (63%), after a similar duration of diabetes before the Diabetes Control and Complications Trial, this prevalence was clearly lower. Current treatment aimed to achieve strict glycemic control has reduced the risk for developing retinopathy.
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| 4. |
- Landin-Olsson, Mona, et al.
(författare)
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Appearance of islet cell autoantibodies after clinical diagnosis of diabetes mellitus
- 1999
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Ingår i: Autoimmunity. - : Informa UK Limited. - 0891-6934 .- 1607-842X. ; 29:1, s. 57-63
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Tidskriftsartikel (refereegranskat)abstract
- Islet cell antibodies (ICA) and glutamic acid decarboxylase antibodies (GAD65Ab) are often present at diagnosis of insulin dependent diabetes mellitus (type I diabetes) and are supposed to decline in level and frequency during the first years of disease. We have analysed ICA and GAD65Ab at onset and after one gear in 395 population based randomly selected 15-34 year old patients newly diagnosed with diabetes mellitus, to study how these autoantibodies persist, disappear and appear and their relation to C-peptide levels. Of the 395 samples 212 (54%) were positive for ICA, 250 (63%) were positive for GAD65Ab and 170 (43%) were positive for both. At follow up after one year, 27/183 (15%) of the ICA negative patients and 25/145 (17%) of the GAD65Ab negative patients had converted to positivity. Among the 103 patients negative for both ICA and GAD65Ab, 16 turned positive for one or both antibodies after one year. Patients converting to positivity for one or the other antibody after one year, had lower C-peptide levels after one year than patients who initially were and remained negative, supporting the hypothesis that these patients have a genuine type I diabetes. In conclusion, newly diagnosed patients may be negative for autoantibodies at diagnosis but develop these antibodies later on during the disease.
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| 5. |
- Littorin, Bengt, et al.
(författare)
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Family characteristics and life events before the onset of autoimmune type 1 diabetes in young adults : A nationwide study
- 2001
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Ingår i: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 24:6, s. 1033-1037
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE - To elucidate whether family characteristics and stressful life events were associated with onset of autoimmune type 1 diabetes in young adults. RESEARCH DESIGN AND METHODS - This investigation was based on a nationwide study (Diabetes Incidence Study in Sweden) of newly diagnosed patients aged 15-34 years. Patients clinically classified as type 1 diabetic with antibodies to islet cells and/or to GAD65 were compared with age- and sex-matched control subjects via questionnaire. The questionnaire covered diabetes heredity, social environment, educational level, and life events experienced during the 12 months before diagnosis. RESULTS - The rate of response was 82% for the diabetic patients and 65% for the control subjects. Questionnaires from 349 diabetic patients and 979 control subjects were considered. Diabetes in relatives was more frequent in the patients (odds ratio [OR] 2.6) who were born in Sweden and whose mothers were of Swedish origin. No major stress factors were detected in the diabetic patients, however, in comparison with the control subjects, the diabetic patients had experienced fewer conflicts with their parents and had less often broken contacts with friends. CONCLUSIONS - Young adults with recent-onset type 1 diabetes were more exposed to heredity for diabetes, but no major prediabetic stress factors were detected. Our study does not directly support the concept that psychosocial stressful life events are involved in the development of autoimmune type 1 diabetes in young adults.
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| 6. |
- Ostman, J., et al.
(författare)
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Gender differences and temporal variation in the incidence of type 1 diabetes : results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002
- 2008
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 263:4, s. 386-394
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To establish the gender difference amongst newly diagnosed type 1 diabetic patients aged 15-34 years, considering age at diagnosis, temporal trend and seasonal variation at time of diagnosis. Study design. A population-based prospective study with a mean annual population at risk of 2.3 million. Setting. All departments of medicine, endocrinology and paediatrics and primary health care units in Sweden. Subjects. Incident cases of diabetes aged 15-34 years at diagnosis 1983-2002. Measure instrument. Basic characteristics of patients at diagnosis were reported by the diagnosing doctor on a standardized form. Level of ascertainment was estimated at 80-90%. Results. Amongst all incident cases (n = 8012), 74% was diagnosed with type 1 diabetes. The mean annual incidence rate of type 1 diabetes was 12.7/100 000, in men 16.4/100 000 and in women 8.9/100 000. The incidence of type 1 diabetes decreased slowly by increasing age but was in all age groups higher in men, yielding an overall male/female ratio of 1.8. In both genders the incidence of type 1 diabetes decreased in average of 1.0% per year. A seasonal pattern with significantly higher incidence during January-March and lower during May-July was seen in both genders. Conclusions. A clear male predominance of type 1 diabetes was seen in all ages. The temporal trend and the seasonal pattern was similar in men and women. Hence, internal factors related to the gender rather than differences in the exposure to environmental factors seem to explain the consistent male-female bias in the postpubertal risk of developing type 1 diabetes.
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| 7. |
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| 8. |
- Svensson, Maria, et al.
(författare)
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Signs of nephropathy may occur early in young adults with diabetes despite modern diabetes management : Results from the nationwide population-based Diabetes Incidence Study in Sweden (DISS)
- 2003
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Ingår i: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 26:10, s. 2903-2909
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE - To estimate the occurrence of early-onset renal involvement in a nationwide population-based cohort of young adults with diabetes in Sweden and relate the findings to glycemic control, type of diabetes, sex, smoking, and blood pressure. RESEARCH DESIGN AND METHODS - The Diabetes Incidence Study in Sweden aims to register all incident cases of diabetes in the age-group 15-34 years. In 1987-1988, 806 patients were reported and invited to participate in a follow-up study focusing on microvascular complications. Of them, 469 subjects participated. The assessment was based on questionnaires (n = 469), blood samples (n = 424), urine samples (n = 251) and, when appropriate, medical records (n = 186). RESULTS - During the follow-up time, median 9 years (range 6-12), 31 of 469 patients (6.6%) with incipient or overt diabetic nephropathy (i.e., micro- or macroalbuminuria) were found, 24 of 426 (5.6%) in type 1 and 7 of 43 (16%) in type 2 diabetic subjects (P = 0.016). Additionally, 24 of 31 patients (77%) had microalbuminuria and 7 (23%) had macroalbuminuria, which mainly occurred in patients with type 2 diabetes. In a Cox regression analysis, high mean HbA1c during the follow-up period and high blood pressure at follow-up increased the risk of developing signs of nephropathy (P = 0.020 and P = 0.003, respectively). Compared with patients with type 1 diabetes, those with type 2 diabetes tended to have an increased risk of renal involvement (P = 0.054) when adjusting for sex, tobacco use, glycemic control, and blood pressure. CONCLUSIONS - Despite modern treatment and self-monitoring of blood glucose, young adult patients with diabetes may still develop renal involvement during the first 10 years of diabetes duration. Inadequate HbA 1c high blood pressure, and type 2 diabetes appear to be risk markers for early occurrence of diabetic nephropathy.
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| 9. |
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| 10. |
- Törn, Carina, et al.
(författare)
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Glutamic acid decarboxylase antibodies (GADA) is the most important factor for prediction of insulin therapy within 3 years in young adult diabetic patients not classified as Type 1 diabetes on clinical grounds
- 2000
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Ingår i: Diabetes/Metabolism Research and Reviews. - 1520-7552 .- 1520-7560. ; 16:6, s. 442-447
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Tidskriftsartikel (refereegranskat)abstract
- Background Differentiation between Type 1 and Type 2 diabetes in adults is difficult at diagnosis. In this study we tested the hypothesis that autoantibodies at diagnosis are predictive for insulin treatment within 3 years in patients initially not classified as Type 1 diabetes. Methods In a nationwide population-based study, blood samples were obtained from 764 patients, all diagnosed with diabetes during a 2-year period. At diagnosis, 583 (76%) were classified as Type 1, 110 (14%) as Type 2 and 71 (9.3%) could not be classified. Results Among patients not classified as Type 1 diabetes, 52 (47%) of Type 2 and 42 (59%) of unclassified patients were positive for islet cell antibodies CICA), glutamic acid decarboxylase antibodies (GADA) or tyrosine phosphatase antibodies (IA-2A). These patients (n=94) had lower body mass index (BMI) (p<0.001) and lower C-peptide (p<0.001) compared to the autoantibody negative patients (n=87). Compared to clinically classified Type 1 diabetes patients positive for autoantibodies (n=477), they have higher BMI (p<0.001), higher C-peptide (p<0.001) and the same levels of ICA, GADA and IA-2A. After 3 years, 93% of autoantibody positive patients initially not classified as Type 1 were on insulin. When ICA, GADA, IA-2A, BMI and C-peptide were tested in a multiple logistic regression, only GADA was signiificant for insulin treatment within 3 years (OR = 18.8; 95% CI 1.8-191) in patients treated with diet or oral drugs at diagnosis. Conclusions A correct classification is difficult in adult diabetic patients. The presence of pancreatic autoantibodies, especially GADA, at diagnosis of diabetes are highly predictive for insulin therapy within 3 years from diagnosis.
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| 11. |
- Amcoff, Mirjam, et al.
(författare)
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Courtship signalling with a labile bilateral signal : males show their best side
- 2009
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 63:12, s. 1717-1725
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individual's behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship display, employing this bilateral morphological trait, reflects trait asymmetry. Finally, we assess whether males respond to phenotypic manipulations of DA with corresponding changes in courtship behaviour. We show that male display behaviour is asymmetric in a manner that reflects asymmetry of their morphological courtship trait and that male display behaviour responds to manipulations of asymmetry of these paddles. Our results thus suggest that males preferentially use their best side and, hence, that males respond adaptively to temporary changes in signal trait asymmetry.
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| 12. |
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| 13. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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A chromosome-level assembly of the seed beetle Callosobruchus maculatus genome with annotation of its repetitive elements
- 2024
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Ingår i: G3. - : Oxford University Press. - 2160-1836. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Callosobruchus maculatus is a major agricultural pest of legume crops worldwide and an established model system in ecology and evolution. Yet, current molecular biological resources for this species are limited. Here, we employ Hi-C sequencing to generate a greatly improved genome assembly and we annotate its repetitive elements in a dedicated in-depth effort where we manually curate and classify the most abundant unclassified repeat subfamilies. We present a scaffolded chromosome-level assembly, which is 1.01 Gb in total length with 86% being contained within the 9 autosomes and the X chromosome. Repetitive sequences accounted for 70% of the total assembly. DNA transposons covered 18% of the genome, with the most abundant superfamily being Tc1-Mariner (9.75% of the genome). This new chromosome-level genome assembly of C. maculatus will enable future genetic and evolutionary studies not only of this important species but of beetles more generally.
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| 14. |
- Arnqvist, Göran, et al.
(författare)
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A chromosome-level assembly of the seed beetle Callosobruchus maculatus genome with annotation of its repetitive elements
- 2024
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Ingår i: G3. - 2160-1836. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Callosobruchus maculatus is a major agricultural pest of legume crops worldwide and an established model system in ecology and evolution. Yet, current molecular biological resources for this species are limited. Here, we employ Hi-C sequencing to generate a greatly improved genome assembly and we annotate its repetitive elements in a dedicated in-depth effort where we manually curate and classify the most abundant unclassified repeat subfamilies. We present a scaffolded chromosome-level assembly, which is 1.01 Gb in total length with 86% being contained within the 9 autosomes and the X chromosome. Repetitive sequences accounted for 70% of the total assembly. DNA transposons covered 18% of the genome, with the most abundant superfamily being Tc1-Mariner (9.75% of the genome). This new chromosome-level genome assembly of C. maculatus will enable future genetic and evolutionary studies not only of this important species but of beetles more generally.
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| 15. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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A possible genomic footprint of polygenic adaptation on population divergence in seed beetles?
- 2022
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Efforts to unravel the genomic basis of incipient speciation are hampered by a mismatch between our toolkit and our understanding of the ecology and genetics of adaptation. While the former is focused on detecting selective sweeps involving few independently acting or linked speciation genes, the latter states that divergence typically occurs in polygenic traits under stabilizing selection. Here, we ask whether a role of stabilizing selection on polygenic traits in population divergence may be unveiled by using a phenotypically informed integrative approach, based on genome-wide variation segregating in divergent populations. We compare three divergent populations of seed beetles (Callosobruchus maculatus) where previous work has demonstrated a prominent role for stabilizing selection on, and population divergence in, key life history traits that reflect rate-dependent metabolic processes. We derive and assess predictions regarding the expected pattern of covariation between genetic variation segregating within populations and genetic differentiation between populations. Population differentiation was considerable (mean F-ST = 0.23-0.26) and was primarily built by genes showing high selective constraints and an imbalance in inferred selection in different populations (positive Tajima's D-NS in one and negative in one), and this set of genes was enriched with genes with a metabolic function. Repeatability of relative population differentiation was low at the level of individual genes but higher at the level of broad functional classes, again spotlighting metabolic genes. Absolute differentiation (d(XY)) showed a very different general pattern at this scale of divergence, more consistent with an important role for genetic drift. Although our exploration is consistent with stabilizing selection on polygenic metabolic phenotypes as an important engine of genome-wide relative population divergence and incipient speciation in our study system, we note that it is exceedingly difficult to firmly exclude other scenarios.
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| 16. |
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| 17. |
- Arnqvist, Göran
(författare)
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Assortative mating by fitness and sexually antagonistic genetic variation
- 2011
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 65:7, s. 2111-2116
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Tidskriftsartikel (refereegranskat)abstract
- Recent documentations of sexually antagonistic genetic variation in fitness have spurred an interest in the mechanisms that may act to maintain such variation in natural populations. Using individual-based simulations, I show that positive assortative mating by fitness increases the amount of sexually antagonistic genetic variance in fitness, primarily by elevating the equilibrium frequency of heterozygotes, over most of the range of sex-specific selection and dominance. Further, although the effects of assortative mating by fitness on the protection conditions of polymorphism in sexually antagonistic loci were relatively minor, it widens the protection conditions under most reasonable scenarios (e. g., under heterozygote superiority when fitness is averaged across the sexes) but can also somewhat narrow the protection conditions under other circumstances. The near-ubiquity of assortative mating in nature suggests that it may contribute to upholding standing sexually antagonistic genetic variation in fitness.
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| 18. |
- Arnqvist, Göran
(författare)
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Comment on "Bateman in Nature: Predation on Offspring Reduces the Potential for Sexual Selection"
- 2013
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 340:6132, s. 549-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Byers and Dunn (Reports, 9 November 2012, p. 802) reported that sexual selection and natural selection are closely related in a wild population of pronghorns. Here, I argue that this conclusion is incorrect. Their main finding is due to the fact that, unsurprisingly, juvenile mortality and juvenile survival are negatively related across years.
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| 19. |
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| 20. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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Concerted evolution of metabolic rate, economics of mating, ecology, and pace of life across seed beetles
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Science. - 0027-8424 .- 1091-6490. ; 119:33
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Tidskriftsartikel (refereegranskat)abstract
- Male-female coevolution has taken different paths among closely related species, but our understanding of the factors that govern its direction is limited. While it is clear that ecological factors, life history, and the economics of reproduction are connected, the divergent links are often obscure. We propose that a complete understanding requires the conceptual integration of metabolic phenotypes. Metabolic rate, a nexus of life history evolution, is constrained by ecological factors and may exert important direct and indirect effects on the evolution of sexual dimorphism. We performed standardized experiments in 12 seed beetle species to gain a rich set of sex-specific measures of metabolic phenotypes, life history traits, and the economics of mating and analyzed our multivariate data using phylogenetic comparative methods. Resting metabolic rate (RMR) showed extensive evolution and evolved more rapidly in males than in females. The evolution of RMR was tightly coupled with a suite of life history traits, describing a pace-of-life syndrome (POLS), with indirect effects on the economics of mating. As predicted, high resource competition was associated with a low RMR and a slow POLS. The cost of mating showed sexually antagonistic coevolution, a hallmark of sexual conflict. The sex-specific costs and benefits of mating were predictably related to ecology, primarily through the evolution of male ejaculate size. Overall, our results support the tenet that resource competition affects metabolic processes that, in turn, have predictable effects on both life history evolution and reproduction, such that ecology shows both direct and indirect effects on male-female coevolution.
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| 21. |
- Arnqvist, Göran, 1961-, et al.
(författare)
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Copulatory behavior, genital morphology, and male fertilization success in water striders
- 1999
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Ingår i: Evolution. - Umea Univ, Dept Anim Ecol, SE-90187 Umea, Sweden. Univ Gothenburg, Dept Zool, SE-40530 Gothenburg, Sweden. : Oxford University Press (OUP). - 0014-3820 .- 1558-5646. ; 53:1, s. 147-156
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Tidskriftsartikel (refereegranskat)
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| 22. |
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| 23. |
- Arnqvist, Göran, 1961-
(författare)
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Cryptic female choice
- 2014
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Ingår i: The Evolution of Insect Mating Systems. - Oxford : Oxford University Press. - 9780199678020 ; , s. 204-220
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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Direct and indirect effects of male genital elaboration in female seed beetles
- 2021
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - London : Royal Society. - 0962-8452 .- 1471-2954. ; 288:1954
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Tidskriftsartikel (refereegranskat)abstract
- Our understanding of coevolution between male genitalia and female traits remains incomplete. This is perhaps especially true for genital traits that cause internal injuries in females, such as the spiny genitalia of seed beetles where males with relatively long spines enjoy a high relative fertilization success. We report on a new set of experiments, based on extant selection lines, aimed at assessing the effects of long male spines on females in Callosobruchus maculatus . We first draw on an earlier study using microscale laser surgery, and demonstrate that genital spines have a direct negative (sexually antagonistic) effect on female fecundity. We then ask whether artificial selection for long versus short spines resulted in direct or indirect effects on female lifetime offspring production. Reference females mating with males from long-spine lines had higher offspring production, presumably due to an elevated allocation in males to those ejaculate components that are beneficial to females. Remarkably, selection for long male genital spines also resulted in an evolutionary increase in female offspring production as a correlated response. Our findings thus suggest that female traits that affect their response to male spines are both under direct selection to minimize harm but are also under indirect selection (a good genes effect), consistent with the evolution of mating and fertilization biases being affected by several simultaneous processes.
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| 25. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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Ecology, the pace‐of‐life, epistatic selection and the maintenance of genetic variation in life‐history genes
- 2023
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 32:17, s. 4713-4724
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary genetics has long struggled with understanding how functional genes under selection remain polymorphic in natural populations. Taking as a starting point that natural selection is ultimately a manifestation of ecological processes, we spotlight an underemphasized and potentially ubiquitous ecological effect that may have fundamental effects on the maintenance of genetic variation. Negative frequency dependency is a well-established emergent property of density dependence in ecology, because the relative profitability of different modes of exploiting or utilizing limiting resources tends to be inversely proportional to their frequency in a population. We suggest that this may often generate negative frequency-dependent selection (NFDS) on major effect loci that affect rate-dependent physiological processes, such as metabolic rate, that are phenotypically manifested as polymorphism in pace-of-life syndromes. When such a locus under NFDS shows stable intermediate frequency polymorphism, this should generate epistatic selection potentially involving large numbers of loci with more minor effects on life-history (LH) traits. When alternative alleles at such loci show sign epistasis with a major effect locus, this associative NFDS will promote the maintenance of polygenic variation in LH genes. We provide examples of the kind of major effect loci that could be involved and suggest empirical avenues that may better inform us on the importance and reach of this process.
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| 26. |
- Arnqvist, Göran
(författare)
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Editorial rejects? : Novelty, schnovelty!
- 2013
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Ingår i: Trends in Ecology & Evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 28:8, s. 448-449
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Because many journals are currently increasing the rate of pre-peer-review editorial rejects, the editorial criteria upon which such decisions are based are very important. Here, I spotlight 'novelty' as a criterion and argue that it is a very problematic decisive factor at this stage of the editorial process.
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| 27. |
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| 28. |
- Arnqvist, Goran, et al.
(författare)
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Falsk marknadsföring om hållbart skogsbruk
- 2022
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Ingår i: Svenska Dagbladet Debatt. - 1101-2412.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Dagens svenska skogsbruk är inte ekologiskt hållbart. Att saluföra det som hållbart är därför – för att tala klarspråk – falsk marknadsföring, skriver forskare.
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| 29. |
- Arnqvist, Göran, et al.
(författare)
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Genetic architecture of metabolic rate : environment specific epistasis between mitochondrial and nuclear genes in an insect
- 2010
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 64:12, s. 3354-3363
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Tidskriftsartikel (refereegranskat)abstract
- The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype x genotype x environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism.
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| 30. |
- Arnqvist, Göran, et al.
(författare)
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Genome size correlates with reproductive fitness in seed beetles
- 2015
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282:1815
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Tidskriftsartikel (refereegranskat)abstract
- The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the 'C-value paradox'. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4-5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.
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| 31. |
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| 32. |
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| 33. |
- Arnqvist, Göran, 1961-, et al.
(författare)
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Mating rate and fitness in female bean weevils
- 2005
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 16:1, s. 123-127
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Tidskriftsartikel (refereegranskat)abstract
- Females of most animal taxa mate with several males during their lifespan. Yet our understanding of the ultimate causes of polyandry is incomplete. For example, it is not clear if and in what sense female mating rates are optimal. Most female insects are thought to maximize their fitness by mating at an intermediate rate, but it has been suggested that two alternative fitness peaks may be observed if multiple costs and benefits interact in determining the relationship between mating rate and fitness. We studied the relationship between female fitness and mating rate in the bean weevil, Callosobruchus maculatus (Coleoptera: Bruchidae), a species in which several distinct direct effects of mating to females have been reported. Our results show that female fitness, measured as lifetime offspring production, is lowest at an intermediate mating rate. We suggest that this pattern is the result of multiple direct benefits to mating (e.g., sperm replenishment and hydration/nutrition effects) in combination with significant direct costs to mating (e.g., injury from male genitalia). Females mating at low rates may efficiently minimize the costs of mating, whereas females mating at high rates instead may maximize the benefits of mating. If common, the existence of bimodal relationships between female mating rate and fitness may help explain the large intra- and interspecific variation in the degree of polyandry often seen in insects.
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| 34. |
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| 35. |
- Arnqvist, Göran, Professor, 1961-
(författare)
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Mixed Models Offer No Freedom from Degress Of Freedom
- 2020
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Ingår i: Trends in Ecology & Evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 35:4, s. 329-335
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Forskningsöversikt (refereegranskat)abstract
- Statistics matter greatly in biology, whether we like it or not. As a discipline with an empirical inclination, we are faced with data every day and we rely on inferential statistical models to make sense of it and to provide us with novel insights. Much of the time, the growing level of complexity and sophistication of the models we put to use in ecology and evolution have led to more appropriate analyses of our data. However, this is not always the case. Here, I draw attention to a classic flaw in inferential statistics that has resurfaced in a new flavor as a result of increased reliance on complex linear mixed models -the multifaceted and disturbingly persistent problem of pseudoreplication.
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| 36. |
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| 37. |
- Arnqvist, Göran, et al.
(författare)
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Negative frequency dependent selection on sympatric mtDNA haplotypes in Drosophila subobscura
- 2016
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 153
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Recent experimental evidence for selection on mitochondrial DNA (mtDNA) has prompted the question as to what processes act to maintain within-population variation in mtDNA. Balancing selection though negative frequency dependent selection (NFDS) among sympatric haplotypes is a possibility, but direct empirical evidence for this is very scarce. Findings: We extend the previous findings of a multi-generation replicated cage experiment in Drosophila subobscura, where mtDNA polymorphism was maintained in a laboratory setting. First, we use a set of Monte Carlo simulations to show that the haplotype frequency dynamics observed are inconsistent with genetic drift alone and most closely match those expected under NFDS. Second, we show that haplotype frequency changes over time were significantly different from those expected under either genetic drift or positive selection but were consistent with those expected under NFSD. Conclusions: Collectively, our analyses provide novel support for NFDS on mtDNA haplotypes, suggesting that mtDNA polymorphism may at least in part be maintained by balancing selection also in natural populations. We very briefly discuss the possible mechanisms that might be involved.
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| 38. |
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| 39. |
- Arnqvist, Göran, et al.
(författare)
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Population differentiation in the swordtail characin (Corynopoma riisei) : a role for sensory drive?
- 2010
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 23:9, s. 1907-1918
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Forskningsöversikt (refereegranskat)abstract
- Sensory drive, where the efficacy of a sexual signal depends on the environment in which it is employed, is a potential mechanism behind divergent evolution of secondary sexual traits. Male swordtail characins are equipped with a narrow and transparent extension of the gill cover with a flag-like structure at its tip. This opercular flag mimics a prey item and is employed by males as a 'lure' to attract the attention of females during mating attempts. We conducted a study of genetic and morphological differentiation across swordtail characin populations throughout their native range in Trinidad. The morphology of the opercular flag varied across populations and several aspects of this variation match the predicted hallmarks of sensory drive. First, morphological differentiation of the flag across populations was unrelated to genetic similarity at neutral genetic markers. Second, the shape of the flag covaried with those aspects of body shape that should reflect adaptation to different feeding regimes. Third, and most importantly, the shape of the flag covaried across populations with those environmental characteristics that should most closely reflect differences in local prey abundance. Overall, our results are consistent with a scenario where the evolution of this male sexual signal tracks food-related shifts in female sensory biases across populations, thus providing at least provisional support for a role for sensory drive in population differentiation.
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| 40. |
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| 41. |
- Arnqvist, Göran, 1961-
(författare)
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Sensory exploitation and sexual conflict
- 2006
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 361:1466, s. 375-386
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Tidskriftsartikel (refereegranskat)abstract
- Much of the literature on male–female coevolution concerns the processes by which male traits and female preferences for these can coevolve and be maintained by selection. There has been less explicit focus on the origin of male traits and female preferences. Here, I argue that it is important to distinguish origin from subsequent coevolution and that insights into the origin can help us appreciate the relative roles of various coevolutionary processes for the evolution of diversity in sexual dimorphism. I delineate four distinct scenarios for the origin of male traits and female preferences that build on past contributions, two of which are based on pre-existing variation in quality indicators among males and two on exploitation of pre-existing sensory biases among females. Recent empirical research, and theoretical models, suggest that origin by sensory exploitation has been widespread. I argue that this points to a key, but perhaps transient, role for sexually antagonistic coevolution (SAC) in the subsequent evolutionary elaboration of sexual traits, because (i) sensory exploitation is often likely to be initially costly for individuals of the exploited sex and (ii) the subsequent evolution of resistance to sensory exploitation should often be associated with costs due to selective constraints. A review of a few case studies is used to illustrate these points. Empirical data directly relevant to the costs of being sensory exploited and the costs of evolving resistance is largely lacking, and I stress that such data would help determining the general importance of sexual conflict and SAC for the evolution of sexual dimorphism.
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| 42. |
- Arnqvist, Göran, et al.
(författare)
-
Sex-role reversed nuptial feeding reduces male kleptoparasitism of females in Zeus bugs (Heteroptera : Veliidae)
- 2006
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 491-493
-
Tidskriftsartikel (refereegranskat)abstract
- Males of a variety of taxa occasionally steal food secured by their mates. In some spiders and insects, males rely entirely on this form of intraspecific kleptoparasitism for their subsistence. However, this male strategy may be costly for females and a variety of different female counteradaptations have been proposed. In Zeus bugs ( Phoreticovelia spp.), males ride on the back of their mates for extended periods and females produce a gland secretion that males feed on. By experimentally occluding the dorsal glands in females and varying food availability, we show that nuptial feeding by females reduces the extent to which the males kleptoparasitize their mates. We suggest that females have, at least in part, evolved this unique form of nuptial feeding as a counteradaptation to reduce the rate of kleptoparasitism by males.
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| 43. |
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| 44. |
- Arnqvist, Göran, et al.
(författare)
-
Sexual Conflict
- 2005
-
Bok (refereegranskat)
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| 45. |
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| 46. |
- Arnqvist, Göran, et al.
(författare)
-
Sexual conflict and the gender load : correlated evolution between population fitness and sexual dimorphism in seed beetles
- 2010
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 277:1686, s. 1345-1352
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Tidskriftsartikel (refereegranskat)abstract
- Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks.
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| 47. |
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| 48. |
- Arnqvist, Göran, 1961-, et al.
(författare)
-
Sexual conflict promotes speciation in insects
- 2000
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Umea Univ, Dept Ecol & Environm Sci, SE-90187 Umea, Sweden. : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 97:19, s. 10460-10464
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Tidskriftsartikel (refereegranskat)abstract
- Speciation rates among extant lineages of organisms vary extensively, but our understanding of the causes of this variation and, therefore, the processes of speciation is still remarkably incomplete. Both theoretical and empirical studies have indicated that sexual selection is important in speciation, but earlier discussions have focused almost exclusively on the potential role of female mate choice. Recent findings of postmating reproductive conflicts of interest between the sexes suggest a quite different route to speciation. Such conflicts may lead to perpetual antagonistic coevolution between males and females and may thus generate rapid evolutionary divergence of traits involved in reproduction. Here, we assess this hypothesis by contrasting pairs of related groups of insect species differing in the opportunity for postmating sexual conflict. Groups where females mate with many males exhibited speciation rates four times as high as in related groups where females mate only once. Our results not only highlight the general importance of postmating sexual selection in speciation, but also support the recent suggestion that sexual conflict is a key engine of speciation.
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| 49. |
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| 50. |
- Arnqvist, Göran, et al.
(författare)
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The effect of epistasis on sexually antagonistic genetic variation
- 2014
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 281:1787, s. 20140489-
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence of segregating sexually antagonistic (SA) genetic variation for fitness in laboratory and wild populations, yet the conditions for the maintenance of such variation can be restrictive. Epistatic interactions between genes can contribute to the maintenance of genetic variance in fitness and we suggest that epistasis between SA genes should be pervasive. Here, we explore its effect on SA genetic variation in fitness using a two locus model with negative epistasis. Our results demonstrate that epistasis often increases the parameter space showing polymorphism for SA loci. This is because selection in one locus is affected by allele frequencies at the other, which can act to balance net selection in males and females. Increased linkage between SA loci had more marginal effects. We also show that under some conditions, large portions of the parameter space evolve to a state where male benefit alleles are fixed at one locus and female benefit alleles at the other. This novel effect of epistasis on SA loci, which we term the 'equity effect', may have important effects on population differentiation and may contribute to speciation. More generally, these results support the suggestion that epistasis contributes to population divergence.
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