Assortative mating in an ecological context:Effects of mate choice errors and relative species abundance on the frequency and asymmetry of hybridization

The frequency and asymmetry of mixed-species mating set the initial stage for the ecological and evolutionary implications of hybridization. How such patterns of mixed-species mating, in turn, are influenced by the combination of mate choice errors and relative species abundance remains largely unknown. We develop a mathematical model that generates predictions for how relative species abundances and mate choice errors affect hybridization patterns. When mate choice errors are small (5%), the highest hybridization frequency occurs when species occur in equal proportions. Furthermore, females of the less abundant species are overrepresented in mixed-species matings. We compare our theoretical predictions with empirical data on naturally hybridizing Ficedula flycatchers and find that hybridization is highest when the two species occur in equal abundance, implying rather high mate choice errors. We discuss ecological and evolutionary implications of our findings and encourage future work on hybrid zone dynamics that take demographic aspects, such as relative species abundance, into account

Latent autoimmune diabetes in adults in Iceland: prevalence, phenotype and relatedness

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenINTRODUCTION: Ninety percent of diabetic individuals in Iceland suffer from type 2 diabetes mellitus. Antibodies against ss-cell components characterise type 1 diabetes, but these antibodies are also found in type 2 diabetic individuals, defined as latent autoimmune diabetes in adults or LADA. The purpose of this investigation was to estimate the prevalence of LADA in Iceland and to describe the phenotype and relatedness of these individuals. MATERIAL AND METHODS: A list of individuals diagnosed with type 2 diabetes was generated from outpatient clinic lists and the Reykjavik Study of the Icelandic Heart Association. A genealogy database (Book of Icelanders; deCODE Genetics) was used to identify all individuals related to these index cases within six meioses. This method identified 950 type 2 diabetic individuals during the years 1998-2000. We analyzed their phenotype and measured glutamic acid decarboxylase antibody (GAD). Kinship coefficient was used to compare the relatedness of those with antibodies to GAD to the relatedness of all type 2 diabetic individuals in the study. RESULTS: 10.1% of men and 9.3% women had measurable antibodies against GAD (non-significant difference). The mean age of GAD positive and GAD negative individuals was comparable (67.1 +/- 10.7 and 68.0 +/- 11.3; years +/- SD). Body mass index was significantly lower (p=0,02) for the GAD positive individuals or 28.2 kg/m(2) (27.2-29.2; 95% CI) vs. 29.7 (29.3-30.1). Of the GAD positive individuals, 47% +/- 9% (95% CI) had the metabolic syndrome as defined by WHO compared with 60 +/- 4% of the GAD negative individuals (p=0.02). The kinship coefficient for GAD positive individuals (n=94) was 6.00x10(-4) compared with 3.93x10(-4) +/- 8.3x10(-5) for 500 random samples (each of 94 individuals) of the whole cohort (p=0.008). CONCLUSION: About 10% of Icelandic type 2 diabetic individuals have antibodies against GAD, which is comparable to the results of other investigators. Icelandic GAD positive type 2 diabetic individuals have less frequently the metabolic syndrome than other type 2 diabetic individuals and GAD positive individuals are significantly more related to each other than type 2 diabetic individuals in general.Tilgangur: 90% sykursjúkra á Íslandi eru með tegund 2 sykursýki (SS2). Meirihluti sjúklinga með tegund 1 sykursýki (SS1) hafa ß-frumumótefni en hafi sjúklingur með SS2 slík mótefni er hann sagður hafa mótefnatengda sykursýki af tegund 2 (MTSS2, latent autoimmune diabetes in adults eða LADA). Tilgangur rannsóknarinnar var að ákvarða algengi MTSS2 á Íslandi og jafnframt að lýsa svipgerð og skyldleika þessara sjúklinga. Efniviður og aðferðir: Búinn var til listi yfir SS2 sjúklinga úr sjúkraskrám og Reykjavíkurrannsókn Hjartaverndar. Ættfræðigagnagrunnur Íslenskrar erfðagreiningar „Íslendingabók“ var notuð til að finna alla sem skyldir voru þessum sjúklingum í sex ættliði. Á árunum 1998-2000 fundust 950 sjúklingar sem greindir voru með SS2. Svipgerð sjúklinganna var ákvörðuð og ELISA notuð til að mæla mótefni gegn Glutamic Acid Decarboxylase (GAD). Skyldleikastuðull var notaður til að bera saman innbyrðis skyldleika GAD-jákvæðra (GADAb+) og skyldleika allra SS2 sjúklinga. Niðurstöður: 10,1% karla og 9,3% kvenna voru GADAb+ (ómarktækur munur). Meðalaldur GADAb+ og GADAb- sjúklinga var sambærilegur (67,1 ± 10,7 og 68,0 ± 11,3; ár ± staðalfrávik). Holdastuðull var marktækt lægri (p=0,02) hjá GADAb+ sjúklingum eða 28,2 kg/m2 (27,2-29,2; 95% öryggismörk) miðað við 29,7 (29,3-30,1) hjá GADAb-. Efnaskiptavilla var til staðar hjá 47 ± 9% (95% öryggismörk) GADAb+ sjúklinganna saman­borið við 60 ± 4% GADAb- sjúklinganna (p=0,02). Skyldleikastuðullinn fyrir GADAb+ sjúk­lingana (n=94) var 6,00×10-4 samanborið við 3,93×10-4 ± 8,3×10-5 fyrir fimm hundruð 94 manna slembi­úr­tök úr öllum SS2 sjúklingahópnum (p=0,008). Ályktun: Um 10% íslenskra SS2 sjúklinga eru GADAb+ sem er sambærilegt við niðurstöður annarra. Íslenskir GADAb+ SS2 sjúklingar eru sjaldnar með efnaskiptavillu og eru marktækt skyldari innbyrðis en SS2 sjúklingahópurinn í heild

Effects of different feeding frequencies on growth, cataract development and histopathology of lumpfish (Cyclopterus lumpus L.)

Under embargo until: 2020-11-13Three duplicate groups of individually tagged lumpfish (mean initial weight: 22.3 ± 2.5 g) were fed either daily (7DW); four days per week (4DW) or three days per week (3DW) at a feeding rate of 2% body weight day−1 for a period of 126 days. There were significant differences in growth rates between the groups with the 7DW fish having the highest growth rates. Cataract prevalence was 53% lower in the 3DW group compared to the 7DW group. Histological examination showed that in some individuals in all three groups there was moderate expansion of the lamina propria in the mid and hind gut regions of the intestine with tissue most likely to represent fibrous tissue with scattered leucocytes. The severity of inflammation appeared to increase the more frequent the fish were fed with the 7DW fish having the highest inflammation score in these tissues. Feeding fish daily also resulted in higher levels of liver vacuolisation and chronic inflammation of the lamina propria in the mid and hind gut region of the intestines. Results from the present study show that restricted feeding regimes can be used to control growth and improve gut and eye health in lumpfish.acceptedVersio

Hydrogen sulfide and traffic-related air pollutants in association with increased mortality: a case-crossover study in Reykjavik, Iceland.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.To study the association between daily mortality and short-term increases in air pollutants, both traffic-related and the geothermal source-specific hydrogen sulfide (H₂S).Population-based, time stratified case-crossover. A lag time to 4 days was considered. Seasonal, gender and age stratification were calculated. Also, the best-fit lag when introducing H₂S >7 µg/m(3) was selected by the Akaike Information Criterion (AIC).The population of the greater Reykjavik area (n=181,558) during 2003-2009.Cases were defined as individuals living in the Reykjavik capital area, 18 years or older (N=138,657), who died due to all natural causes (ICD-10 codes A00-R99) other than injury, poisoning and certain other consequences of external causes, or cardiovascular disease (ICD-10 codes I00-I99) during the study period.Percentage increases in risk of death (IR%) following an interquartile range increase in pollutants.The total number of deaths due to all natural causes was 7679 and due to cardiovascular diseases was 3033. The interquartile range increased concentrations of H₂S (2.6 µg/m(3)) were associated with daily all natural cause mortality in the Reykjavik capital area. The IR% was statistically significant during the summer season (lag 1: IR%=5.05, 95% CI 0.61 to 9.68; lag 2: IR%=5.09, 95% CI 0.44 to 9.97), among males (lag 0: IR%=2.26, 95% CI 0.23 to 4.44), and among the elderly (lag 0: IR%=1.94, 95% CI 0.12 to 1.04; lag 1: IR%=1.99, 95% CI 0.21 to 1.04), when adjusted for traffic-related pollutants and meteorological variables. The traffic-related pollutants were generally not associated with statistical significant IR%s.The results suggest that ambient H₂S air pollution may increase mortality in Reykjavik, Iceland. To the best of our knowledge, ambient H₂S exposure has not previously been associated with increased mortality in population-based studies and therefore the results should be interpreted with caution. Further studies are warranted to confirm or refute whether H₂S exposure induces premature deaths.University of Iceland HI20109

The Montana Kaimin, January 17, 1922

Student newspaper of the University of Montana, Missoula.https://scholarworks.umt.edu/studentnewspaper/1675/thumbnail.jp

Seagrass wasting disease varies with salinity and depth in natural Zostera marina populations

In the 1930s the wasting disease pathogen Labyrinthula zosterae is believed to have killed 90% of the temperate seagrass Zostera marina in the Atlantic Ocean. Despite the devastating impact of this disease the host–pathogen interaction is still poorly understood, and few field studies have investigated factors correlating with the prevalence and abundance of L. zosterae. This study measures wasting disease in natural populations of Z. marina, showing a strong correlation between the disease and both salinity and water depth. No infection was detected in Z. marina shoots from low salinity (13–25 PSU) meadows, whereas most shoots carried the disease in high salinity (25–29 PSU). Shallow (1 m) living Z. marina shoots were also more infected compared to shoots in deeper (5 m) meadows. In addition, infection and transplantation experiments showed that Z. marina shoots from low salinity meadows with low pathogen pressure were more susceptible to L. zosterae infection. The higher susceptibility could not be explained by lower content of inhibitory defense compounds in the shoots. Instead, extracts from all Z. marina shoots significantly reduced pathogen growth, suggesting that Z. marina contains inhibitory compounds that function as a constitutive defense. Overall, the results show that seagrass wasting disease is common in natural Z. marina populations in the study area and that it increases with salinity and decreases with depth. Our findings also suggest that low salinity areas can act as a refuge against seagrass wasting disease

Seven up acts as a temporal factor during two different stages of neuroblast 5-6 development

Drosophila embryonic neuroblasts generate different cell types at different time points. This is controlled by a temporal cascade of HbrKrrPdmrCasrGrh, which acts to dictate distinct competence windows sequentially. In addition, Seven up (Svp), a member of the nuclear hormone receptor family, acts early in the temporal cascade, to ensure the transition from Hb to Kr, and has been referred to as a ‘switching factor’. However, Svp is also expressed in a second wave within the developing CNS, but here, the possible role of Svp has not been previously addressed. In a genetic screen for mutants affecting the last-born cell in the embryonic NB5-6T lineage, the Ap4/FMRFamide neuron, we have isolated a novel allele of svp. Expression analysis shows that Svp is expressed in two distinct pulses in NB5-6T, and mutant analysis reveals that svp plays two distinct roles. In the first pulse, svp acts to ensure proper downregulation of Hb. In the second pulse, which occurs in a Cas/Grh double-positive window, svp acts to ensure proper sub-division of this window. These studies show that a temporal factor may play dual roles, acting at two different stages during the development of one neural lineage.This work was supported by the Swedish Research Council, by the Swedish Strategic Research Foundation, by the Knut and Alice Wallenberg foundation, by the Swedish Brain Foundation, by the Swedish Cancer Foundation, by the Swedish Royal Academy of Sciences [S.T.], and by a grant from the Spanish Ministerio de Ciencia e Innovación [BFU-2008-04683-C02-02 to L.T.]

Lactobacilli with superoxide dismutase-like or catalase activity are more effective in alleviating inflammation in an inflammatory bowel disease mouse model

Purpose: Some lactobacilli, which possess superoxide dismutase-like activity and catalase activity naturally, have strong antioxidative properties. The aim of this study was to identify such strains and check which of them play a crucial role in alleviating intestinal inflammation. Methods: We selected two Lactobacillus strains for use in animal studies: L. plantarum 30B (which has the highest catalase activity) and L. acidophilus 900 (which has the highest dismutase-like activity). Forty mice (C57B1/6J) were divided into four experimental groups with ten mice in each group. Group I (control group) was not supplemented with Lactobacillus, group II (catalase group) was orally supplemented with L. plantarum 30B, group III (dismutase-like group) was supplemented with L. acidophilus 900, and group IV (mixed group) was supplemented with both Lactobacillus strains. For 23 days, the temperature and body mass of each mouse were recorded and fecal samples for microbiological examination were collected. On day 23, the animals were sacrificed, and their intestines were removed for microbiological and histopathological studies. Results: Compared to the control group, the highest drop in the body temperature was observed in groups II (P,0.05) and IV (P,0.05). Similarly, groups II (P,0.05) and IV (P,0.05) had the highest drop in body mass. Moreover, histopathological evaluation of colon fragments showed intracryptic abscesses in these groups. Group III mice showed most limited degree of inflammation. Conclusion: Lactobacillus strains with dismutase-like activity are more effective in alleviating intestinal inflammation than strains producing catalase, suggesting that superoxide anion radical decomposition is crucial in this process

Genkartlegging av bevaringsverdige saueraser

Norsk genressurssenter har, i samarbeid med Norsk Sau og Geit, raselag og avlsbesetninger, kartlagt forekomsten av blant annet finnegenvarianten hos rygjasau, steigarsau, grå trøndersau og gammelnorsk spælsau. I tillegg har vi sett på genetiske distanser mellom norske saueraser.Genkartlegging av bevaringsverdige saueraserpublishedVersio