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Repeated climatic and vegetation changes during the Pleistocene have shaped biodiversity in Northern Europe including Denmark. The Northern Birch Mouse ( Sicista betulina ) was one of the first small rodent species to colonize Denmark after the Late Glacial Maximum. This study analyses complete mitochondrial genomes and two nuclear genes of the Northern Birch Mouse to investigate the phylogeographical pattern in North-western Europe and test whether the species colonized Denmark through several colonization events. The latter was prompt by (i) the present-day distinct northern and southern Danish distribution and (ii) the subfossil record of Northern Birch Mouse, supporting early Weichselian colonization. Samples from Denmark, Norway, Sweden, Russia, Latvia, Estonia, and Slovakia were included. Mitogenomes were obtained from 54 individuals, all representing unique mitogenomes supporting high genetic variation. Bayesian phylogenetic analysis identified two distinct evolutionary linages in Northern Europe diverging within the Elster glaciation period. The results of the two nuclear genomes showed lower genetic differentiation but supported the same evolutionary history. This suggests an allopatric origin of the clades followed by secondary contact. Individuals from southern Denmark were only found in one clade, while individuals from other areas, including northern Denmark, were represented in both clades. Nevertheless, we found no evidence for repeated colonization's explaining the observed fragmented distribution of the species today. The results indicated that the mitogenome pattern of the Northern Birch Mouse population in southern Denmark was either (i) due to the population being founded from northern Denmark, (ii) a result of climatic and anthropogenic effects reducing population size increasing genetic drift or (iii) caused by sampling bias., Competing Interests: The authors declare no competing interests., (© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Background: The two North Atlantic eel species, the European and the American eel, represent an ideal system in which to study parallel selection patterns due to their sister species status and the presence of ongoing gene flow. A panel of 80 coding-gene SNPs previously analyzed in American eel was used to genotype European eel individuals (glass eels) from 8 sampling locations across the species distribution. We tested for single-generation signatures of spatially varying selection in European eel by searching for elevated genetic differentiation using FST-based outlier tests and by testing for significant associations between allele frequencies and environmental variables., Results: We found signatures of possible selection at a total of 11 coding-gene SNPs. Candidate genes for local selection constituted mainly genes with a major role in metabolism as well as defense genes. Contrary to what has been found for American eel, only 2 SNPs in our study correlated with differences in temperature, which suggests that other explanatory variables may play a role. None of the genes found to be associated with explanatory variables in European eel showed any correlations with environmental factors in the previous study in American eel., Conclusions: The different signatures of selection between species could be due to distinct selective pressures associated with the much longer larval migration for European eel relative to American eel. The lack of parallel selection in North Atlantic eels could also be due to most phenotypic traits being polygenic, thus reducing the likelihood of selection acting on the same genes in both species.

Local adaptation and its underlying molecular basis has long been a key focus in evolutionary biology. There has recently been increased interest in the evolutionary role of plasticity and the molecular mechanisms underlying local adaptation. Using transcriptome analysis, we assessed differences in gene expression profiles for three brown trout (Salmo trutta) populations, one resident and two anadromous, experiencing different temperature regimes in the wild. The study was based on an F2 generation raised in a common garden setting. A previous study of the F1 generation revealed different reaction norms and significantly higher QST than FST among populations for two early life-history traits. In the present study we investigated if genomic reaction norm patterns were also present at the transcriptome level. Eggs from the three populations were incubated at two temperatures (5 and 8 degrees C) representing conditions encountered in the local environments. Global gene expression for fry at the stage of first feeding was analysed using a 32k cDNA microarray. The results revealed differences in gene expression between populations and temperatures and population × temperature interactions, the latter indicating locally adapted reaction norms. Moreover, the reaction norms paralleled those observed previously at early life-history traits. We identified 90 cDNA clones among the genes with an interaction effect that were differently expressed between the ecologically divergent populations. These included genes involved in immune- and stress response. We observed less plasticity in the resident as compared to the anadromous populations, possibly reflecting that the degree of environmental heterogeneity encountered by individuals throughout their life cycle will select for variable level of phenotypic plasticity at the transcriptome level. Our study demonstrates the usefulness of transcriptome approaches to identify genes with different temperature reaction norms. The responses observed suggest that populations may vary in their susceptibility to climate change.

Drosophila melanogaster is frequently used in ageing studies to elucidate which mechanisms determine the onset and progress of senescence. Lines selected for increased longevity have often been shown to perform as well as or superior to control lines in life history, stress resistance and behavioural traits when tested in the laboratory. Functional senescence in longevity selected lines has also been shown to occur at a slower rate. However, it is known that performance in a controlled laboratory setting is not necessarily representative of performance in nature. In this study the effect of ageing, environmental temperature and longevity selection on performance in the field was tested. Flies from longevity selected and control lines of different ages (2, 5, 10 and 15 days) were released in an environment free of natural food sources. Control flies were tested at low, intermediate and high temperatures, while longevity selected flies were tested at the intermediate temperature only. The ability of flies to locate and reach a food source was tested. Flies of intermediate age were generally better at locating resources than both younger and older flies, where hot and cold environments accelerate the senescent decline in performance. Control lines were better able to locate a resource compared to longevity selected lines of the same age, suggesting that longevity comes at a cost in early life field fitness, supporting the antagonistic pleiotropy theory of ageing., (© 2013.)

Selection for increased life span in Drosophila melanogaster has been shown to correlate with decreased early fecundity and increased fecundity later in life. This phenomenon has been ascribed to the existence of trade-offs in which limited resources can be invested in either somatic maintenance or reproduction. In our longevity selection lines, we did not find such a trade-off. Rather, we find that females have similar or higher fecundity throughout life compared to non-selected controls. To determine whether increased longevity affects responses in other traits, we looked at several stress resistance traits (chill coma recovery, heat knockdown, desiccation and starvation), geotactic behaviour, egg-to-adult viability, body size, developmental time as well as metabolic rate. Longevity selected flies were more starvation resistant. However, in females longevity and fecundity were not negatively correlated with the other traits assayed. Males from longevity selected lines were slower at recovering from a chill induced coma and resting metabolic rate increased with age, but did not correlate with life span., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Elucidating genes that affect life span or that can be used as biomarkers for ageing has received attention in diverse studies in recent years. Using model organisms and various approaches several genes have been linked to the longevity phenotype. For Drosophila melanogaster those studies have usually focussed on one sex and on flies originating from one genetic background, and results from different studies often do not overlap. Using D. melanogaster selected for increased longevity we aimed to find robust longevity related genes by examining gene expression in both sexes of flies originating from different genetic backgrounds. Further, we compared expression changes across three ages, when flies were young, middle aged or old, to examine how candidate gene expression changes with the onset of ageing. We selected 10 genes based on their expression differences in prior microarray studies. For about 50% of these we confirmed their potential as a candidate longevity gene. We found one robust candidate gene for longevity, CG32638. Three other genes, CG8934, mRpS10 and Spn43Ad, showed a tendency to be involved in life span determination in both backgrounds tested., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The small heat shock gene (shsp) cluster of Drosophila buzzatii was sequenced and the gene order and DNA sequence were compared with those of the shsps in Drosophila melanogaster. The D. buzzatii shsp cluster contains an inversion and a duplication of hsp26. A phylogenetic tree was constructed based on hsp26 genes from several Drosophila species of the Sophophora and Drosophila subgenera. The tree shows first a separation of the Sophophora and the Drosophila subgenera and then the Drosophila subgenus is divided into the Hawaiian Drosophila and the repleta/virilis groups. Only the latter contain a duplicated hsp26. Comparing the gene organisation of the shsp cluster shows that all the Drosophila subgenus species contain the inversion. Putative heat shock elements (HSE) were found in the promoters of all the shsp and putative regulator elements for tissue specific expression were found in the promoter of hsp23, hsp27 and one of the hsp26 genes. hsp23 was found to be polymorphic for four non-synonymous changes that all lead to exchange of a Valine. The duplicated hsp26 gene in D. buzzatii (phsp26) was polymorphic for two non-synonymous changes. The allele frequencies of these variants were determined in nine D. buzzatii populations covering most of its distribution in Australia using high-resolution melting curves. The allele frequencies of one of the hsp23 variants showed a significant linear regression with longitude and the pooled frequency of the four Valine changes of hsp23 in the nine populations showed a significant linear regression with longitude and with a composite measure of climatic variables.

It has been claimed that Danish cases of human ascariasis have been acquired either during travel to other countries or through consumption of untreated food imported from areas where human ascariasis is endemic. An epidemiological survey in Viborg County indicated, however, that pigs are the primary source of the infection. Our population-genetic investigations have now confirmed this hypothesis. The main transmission route for human ascariasis in developed countries therefore seems to be from pigs to people; thus, it is essential that contact with pig manure be avoided, especially by young children.

In searching for species-specific DNA sequences of microphallid species (Digenea, Trematoda) we examined the ribosomal internal transcribed spacer regions (ITS) of three closely related species (Levinseniella group) hosted by mud snails (first intermediate host) and marine crustaceans (second intermediate host). In the ITS1 region we found consistent patterns of repeating sequences of 130 bp. Within each main repeat there was a varying number of subrepeats specific for each of the species. All repeats including subrepeats were identified by a similar starting sequence: 5'-CCTGTGG-3'. As this sequence has close resemblance to the chi sequence 5'-GCTGGTGG-3' found in phage lambda we speculate if it serves the same function as a recombination hotspot. Alternatively but less likely, it could be an inactive, mutational relic of a sequence that once served this purpose.

A preliminary epidemiological survey indicated an association between Ascaris infections in Danish patients and contact with pigs or pig manure. In the present study, we compared Ascaris worms collected from humans and Ascaris worms collected from pigs by amplified fragment length polymorphism (AFLP) analysis, a technique for whole-genome fingerprinting, and by PCR-linked restricted fragment length polymorphism (PCR-RFLP) analysis of the internal transcribed spacer region of nuclear rDNA. The AFLP data were analyzed by distance- and model-based clustering methods. These results assigned Ascaris worms from Danish patients to a cluster different from that for worms from humans in other geographic areas. In contrast, worms from humans and pigs in Denmark were assigned to the same cluster. These results were supported by the PCR-RFLP results. Thus, all of the examined Danish patients had acquired Ascaris infections from domestic pigs; ascariasis may therefore be considered a zoonotic disease in Denmark.

We here analyze the population structure in the pig roundworm, Ascaris suum, among domestic pigs in Denmark using a whole-genome DNA fingerprinting technique, "amplified fragment length polymorphism" (AFLP) analysis. With these data, we can extract absolute gene frequency variance components and G-statistics for 135 independent nucleotide polymorphisms. The average proportion of total variance partitioned between Jutland and Zealand is less than 3% of the total variance, implying no restriction in gene flow between worms from different regions in Denmark. The average gene frequency difference between two farms widely separated in Jutland represents 5% of the total genetic variance of these two farms combined. Conversely, worms from different hosts within these two farms are more subdivided, with an average of 12% of the total variance in gene frequencies within farms being distributed between hosts. This result implies substantial single generation inbreeding due to founder effects in the establishment of adult worms in single hosts. Absolute variance components extracted from the gene diversities also showed significant differences, with the among-host variance being greater that the between-farm and between-region values. This little geographical variation is discussed in relation to the hierarchic structure of the Danish swine production system. Comparison of our results with other studies on parasitic roundworms, suggests that patterns of host dispersal effectively control patterns of worm gene flow. Furthermore, the potential spread of anthelminth resistance among A. suum may thus be rapid, due to the flow of infected hosts within the domestic swine stocks in Denmark.

The millipede, Nemasoma varicorne, represents a textbook example of geographic parthenogenesis with thelytokous populations being distributed north, east, south and west of the distribution of the bisexual ancestor in the deciduous forests of central Europe. We here describe variation in amplified fragment length polymorphisms (AFLP's) in sympatric bisexual and thelytokous populations of N. varicorne in Denmark and compare the relationships of Danish populations with animals from The Czech Republic, England and Poland. Thelytokes from Denmark, England and Poland form a monophyletic cluster that differs from bisexuals from Denmark and Czechia for about 30% of the fragments. A single clone is widely spread over Denmark (34 of 38 localities), with rare clones being detected at four other localities. The phylogenetic pattern implies strongly that thelytoky evolved prior to the post-glacial colonization of northern Europe. This further suggests that the two forms have interacted extensively during this colonization and that the thelytokes have been excluded from older forests by competition with the bisexual forms. Our results further suggest that the success of the thelytokous form, at least in Denmark, is not due to abundant clonal diversity as hypothesized by the frozen niche variation model.

B lymphocytes are responsible for antigen uptake and presentation, as well as antibody production. These reactions require close cell-to-cell contact between B lymphocytes and monocytes. In this study we demonstrate that interleukin 8 (IL-8), gamma-immune protein 10 (gammaIP-10) and tumour necrosis factor alpha (TNF-alpha) all induce a significant chemokinetic response of human B lymphocytes. Among the cytokines tested, rIL-8 was the strongest B lymphocyte migratory factor with a migratory index (MI) of 2.03+/-0.32, (P<0.002), followed by rTNF-alpha (MI=1.89+/-0.17, P<0.001) and rgammaIP-10 (MI=1.63+/-0.17, P<0.001). We did not observe B lymphocyte migration towards rIL-1alpha, rIL-2, rIL-4, rIL-10, interferon gamma (rINF-gamma) or transforming growth factor beta (rTGF-beta). Furthermore, we report that human B lymphocytes have a constitutive IL-8 mRNA expression and protein secretion in vitro. Resting as well as stimulated B lymphocytes secrete on average 1.5 ng IL-8/ml medium/24 h (2x10(6) B lymphocytes). Our data indicate a possible mechanism by which B lymphocytes make contact with other cells, during immuno-inflammatory processes., (Copyright 1997 Academic Press Limited.)

A novel isoform of human elongation factor-1 alpha (EF-1 alpha 2) has been characterised. It shows a high similarity to other EF-1 alpha proteins, especially to a rat EF-1 alpha variant and it has all the characteristics of a functional EF-1 alpha protein. The pattern of expression of both EF-1 alpha 2 and EF-1 alpha was analysed in different human tissues. This showed that the two proteins were differentially expressed, EF-1 alpha 2 was expressed in brain, heart, skeletal muscle and in the transformed cell lines AMA and K14, but was undetectable in other tissues and in both primary and transformed human fibroblasts. EF-1 alpha was expressed in brain, placenta, lung, liver, kidney, pancreas and in all the cell lines that we have analysed but barely detectable in heart and skeletal muscle.

The EF-1 alpha O gene of Xenopus laevis is a stage-specific gene, being transcribed in oogonia and oocytes, but not in postmeiotic germ cells and terminally differentiated cells. We found that two trans-acting factors from oocyte nuclear extract are able to interact with a DNA sequence in the 5'-upstream region of the EF-1 alpha O gene. Methylation interference experiments suggested that the two factors recognised the same DNA element. Gel retardation assays indicated that part of the protein binding site could be confined to a 21 bp sequence, located between -51 and -72, relative to the cap site. Interestingly, this region shares great homology to a negative regulatory segment in the promoter of the TFIIIA gene, another developmentally regulated gene.

In Xenopus laevis, the gene encoding the elongation factor 1-alpha variant EF-1 alpha O, where O stands for oocyte, is expressed in oocytes and early embryos. A genomic library from X. laevis was screened with a cDNA probe coding for EF-1 alpha O. Two recombinant phages were isolated, one of which carries an entire EF-1 alpha O gene. This clone was characterized by restriction enzyme mapping and sequencing. Comparison of cDNA and genomic sequences revealed that EF-1 alpha O consists of seven exons spanning about 6.5 kb. The structure of the gene is very homologous to the human EF-1 alpha gene, as all locations of the splice junctions are conserved between the two genes. The sequence immediately upstream from the transcription start point (tsp) contains a CCAAT box, but does not contain either a TATA box or a Sp1-binding site. Interestingly, this sequence has a sequence homologous to the negative regulatory element from the TFIIIA promoter. A region located about 400 bp upstream from the tsp contains an additional number of possible regulatory sequence elements. The first intron contains G + C-rich elements which exist both isolated and as part of longer inverted repeats. Furthermore, one octamer and four Sp1-binding sites are found in this intron.

A genomic library of Mycoplasma pneumoniae was constructed by cloning partial Sau3A-digested genomic DNA into the expression plasmids pEX1 to pEX3. The recombinant clones were screened for production of M. pneumoniae P1-antigen by an in situ colony enzyme-linked immunosorbent assay (ELISA) blot method with a monospecific rabbit antiserum raised against the surface protein P1. The length of the translated P1-sequence and the size of the inserted DNA were determined. By comparison it was shown that six clones contained DNA fragments coding for an internal part of the P1-protein and eight clones code for the C-terminal part of terminated P1-protein. In reactions against sera from patients suffering from M. pneumoniae infection and sera from healthy persons, one of the internal clones and five of the C-terminal clones reacted with one or two of the patient sera, but only one clone reacted with all patient sera.

The DNA sequence of one of the 16S rRNA genes (cistron rrnA) of Mycoplasma strain PG50 was determined. It is 1523 bp long and has about 70% homology to the sequence of Escherichia coli 16S rRNA (rrnB). The G + C content of the sequence is 48% compared with 56% G + C in the E. coli sequence. The secondary structure is formed and it is determined that most of the differences between the two sequences are seen in stems while loops in the secondary structure are conserved. A detailed description of differences and similarities to known sequences and rRNA oligonucleotide catalogues is given, and this information is used to discuss functional properties and phylogenetic relations of mycoplasma 16S rRNA.

A library of DNA fragments from Mycoplasma sp. strain PG50 has been made in the vector pBR325. Analysis in Escherichia coli minicells of randomly picked clones from this library demonstrated that many plasmids can promote synthesis of mycoplasma protein in the E. coli genetic background. Screening with labeled rRNA identified plasmids with sequences from the beginning of the rRNA cistron to about two-thirds within the gene for 23S rRNA. Use of these plasmids as probes allowed an accurate determination of the number of RNA cistrons as two, and demonstrated that the cistrons are more than 20 kbp apart. The DNA sequence of 16S rRNA and the surrounding control regions has been determined.