Social kin associations and genetic structuring of striped dolphin populations (Stenella coeruleoalba) in the Mediterranean Sea

We investigated hierarchical patterns of genetic subdivision, and assessed kinship within and between social groups of striped dolphins (Stenella coeruleoalba) in the Tyrrhenian Sea. A total of 165 samples were analysed at eight microsatellite DNA loci, including outgroup samples from the Adriatic, Scotland and Spain for population-level comparisons. We found population genetic structure within the Mediterranean basin, including small but significant differentiation between the Adriatic and Tyrrhenian Seas (FST=0.0047, P=0.008), and between putative 'inshore' and 'offshore' (FST=0.0217, P=0.005) populations in the Tyrrhenian Sea. Assessment of kinship within and among 12 association groups showed higher average kinship for females within than between groups, and smaller groups showed higher average kinship. Comparisons of relatedness for both sexes showed a significant difference between males and females, with females more likely to associate with adult kin. Together these data emphasize the importance of the social cohesion of kin in small groups to the structuring of striped dolphin populations in this environment.     

Genetic isolation of a now extinct population of bottlenose dolphins (Tursiops truncatus)

A number of dolphin species, though highly mobile, show genetic structure among parapatric and sometimes sympatric populations. However, little is known about the temporal patterns of population structure for these species. Here, we apply Bayesian inference and data from ancient DNA to assess the structure and dynamics of bottlenose dolphin (Tursiops truncatus) populations in the coastal waters of the UK. We show that regional population structure in UK waters is consistent with earlier studies suggesting local habitat dependence for this species in the Mediterranean Sea and North Atlantic. One genetically differentiated UK population went extinct at least 100 years ago and has not been replaced. The data indicate that this was a local extinction, and not a case of historical range shift or contraction. One possible interpretation is a declining metapopulation and conservation need for this species in the UK.     

Dietary differentiation and the evolution of population genetic structure in a highly mobile carnivore

Recent studies on highly mobile carnivores revealed cryptic population genetic structures correlated to transitions in habitat types and prey species composition. This led to the hypothesis that natal-habitat-biased dispersal may be responsible for generating population genetic structure. However, direct evidence for the concordant ecological and genetic differentiation between populations of highly mobile mammals is rare. To address this we analyzed stable isotope profiles (δ(13)C and δ(15)N values) for Eastern European wolves (Canis lupus) as a quantifiable proxy measure of diet for individuals that had been genotyped in an earlier study (showing cryptic genetic structure), to provide a quantitative assessment of the relationship between individual foraging behavior and genotype. We found a significant correlation between genetic distances and dietary differentiation (explaining 46% of the variation) in both the marginal test and crucially, when geographic distance was accounted for as a co-variable. These results, interpreted in the context of other possible mechanisms such as allopatry and isolation by distance, reinforce earlier studies suggesting that diet and associated habitat choice are influencing the structuring of populations in highly mobile carnivores.     

Generation of VNTRs and heteroplasmy by sequence turnover in the mitochondrial control region of two elephant seal species

We describe an unusual repetitive DNA region located in the 3′ end of the light (L)-strand in the mitochondrial control region of two elephant seal species. The array of tandem repeats shows both VNTR (variable-number tandem repeat) and sequence variation and is absent from 12 compared mammalian species, except for the occurrence in the same location of a distinct repetitive region in rabbit mtDNA and a similar repeat in the harbor seal. The sequence composition and arrangement of the repeats differ considerably between the northern elephant seal (Mirounga angustirostris) and the southern species (M. leonina) despite an estimated divergence time of 1 MY (based on an mtDNA-RNA gene and the nonrepetitive control region). Analysis of repeat sequence relationships within and between species indicate that divergence in sequence and structure of repeats has involved both slippagelike and unequal crossingover processes of turnover, generating very high levels of divergence and heteroplasmy. Presented at the NATO Advanced Research Workshop onGenome Organization and Evolution, Spetsai, Greece, 16–22 September 1992     

Glioblastomas acquire myeloid-affiliated transcriptional programs via epigenetic immunoediting to elicit immune evasion

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In vivo comparison of 2′‐O‐methyl phosphorothioate and morpholino antisense oligonucleotides for Duchenne muscular dystrophy exon skipping

Background

Antisense‐mediated exon skipping is a putative treatment for Duchenne muscular dystrophy (DMD). Using antisense oligonucleotides (AONs), the disrupted DMD reading frame is restored, allowing generation of partially functional dystrophin and conversion of a severe Duchenne into a milder Becker muscular dystrophy phenotype. In vivo studies are mainly performed using 2′‐O‐methyl phosphorothioate (2OMePS) or morpholino (PMO) AONs. These compounds were never directly compared.

Methods

mdx and humanized (h)DMD mice were injected intramuscularly and intravenously with short versus long 2OMePS and PMO for mouse exon 23 and human exons 44, 45, 46 and 51.

Results

Intramuscular injection showed that increasing the length of 2OMePS AONs enhanced skipping efficiencies of human exon 45, but decreased efficiency for mouse exon 23. Although PMO induced more mouse exon 23 skipping, PMO and 2OMePS were more comparable for human exons. After intravenous administration, exon skipping and novel protein was shown in the heart with both chemistries. Furthermore, PMO showed lower intramuscular concentrations with higher exon 23 skipping levels compared to 2OMePS, which may be due to sequestration in the extracellular matrix. Finally, two mismatches rendered 2OMePS but not PMO AONs nearly ineffective.

Conclusions

The results obtained in the present study indicate that increasing AON length improves skipping efficiency in some but not all cases. It is feasible to induce exon skipping and dystrophin restoration in the heart after injection of 2OMePS and unconjugated PMO. Furthermore, differences in efficiency between PMO and 2OMePS appear to be sequence and not chemistry dependent. Finally, the results indicate that PMOs may be less sequence specific than 2OMePS. Copyright © 2009 John Wiley & Sons, Ltd.     

Fluctuating asymmetry in populations of British roe deer (Capreolus capreolus) following historical bottlenecks and founder events

The potential impact of population bottlenecks and founder events on genetic diversity and indirect measures of fitness (such as fluctuating asymmetry; FA) has important conservation implications. Here we take advantage of historical events that generated a remnant roe deer (Capreolus capreolus) population in the north of the British Isles that retained diversity, while populations in the south were apparently extirpated during the early mediaeval era. The southern population was later re-established from small founder populations of introduced European roe deer starting in the 19th century. We assess the impact of these events, using the northern remnant population as a reference, based on measures of FA at 16 bilateral cranial traits. Comparing the northern and southern populations we find evidence of differential impact on both the level of FA and the relationship between FA and levels of genetic diversity.     

Are semi-aquatic bugs (Heteroptera: Nepomorpha) indicators of hydrological stability of permanent ponds?

The composition of semi-aquatic bug communities from eight permanent ponds from southern Transylvania was investigated between 2001 and 2004. Three of the ponds were sampled repeatedly throughout the active period of the year, while the other five were sampled only once. Microvelia reticulata (Burmeister, 1835) and Gerris argentatus Schummel, 1832 were the dominant species from the thoroughly investigated habitats. Statistical analysis proved that each of the sampled species has specific habitat preferences in relation to the modifications of the hydrological regime of the ponds (reflected by the modifications of open water areas, station sizes, and percentages of vegetation coverage). The results, obtained from the three habitats investigated throughout the active period, were confirmed by the samples taken from the other five habitats opening the discussion about the use of semi-aquatic bug communities as bioindicators of the hydrological regime for permanent ponds.