Haldane’s formula in Cannings models: the case of moderately strong selection

For a class of Cannings models we prove Haldane’s formula, $$\pi (s_N) \sim \frac{2s_N}{\rho ^2}$$ π ( s N ) ∼ 2 s N ρ 2 , for the fixation probability of a single beneficial mutant in the limit of large population size N and in the regime of moderately strong selection, i.e. for $$s_N \sim N^{-b}$$ s N ∼ N - b and $$0< b<1/2$$ 0 < b < 1 / 2 . Here, $$s_N$$ s N is the selective advantage of an individual carrying the beneficial type, and $$\rho ^2$$ ρ 2 is the (asymptotic) offspring variance. Our assumptions on the reproduction mechanism allow for a coupling of the beneficial allele’s frequency process with slightly supercritical Galton–Watson processes in the early phase of fixation.

Estimating the strength of selection for new SARS-CoV-2 variants

Controlling the SARS-CoV-2 pandemic becomes increasingly challenging as the virus adapts to human hosts through the continual emergence of more transmissible variants. Simply observing that a variant is increasing in frequency is relatively straightforward, but more sophisticated methodology is needed to determine whether a new variant is a global threat and the magnitude of its selective advantage. We present two models for quantifying the strength of selection for new and emerging variants of SARS-CoV-2 relative to the background of contemporaneous variants. These methods range from a detailed model of dynamics within one country to a broad analysis across all countries, and they include alternative explanations such as migration and drift. We find evidence for strong selection favoring the D614G spike mutation and B.1.1.7 (Alpha), weaker selection favoring B.1.351 (Beta), and no advantage of R.1 after it spreads beyond Japan. Cutting back data to earlier time horizons reveals that uncertainty is large very soon after emergence, but that estimates of selection stabilize after several weeks. Our results also show substantial heterogeneity among countries, demonstrating the need for a truly global perspective on the molecular epidemiology of SARS-CoV-2.

Genome of the estuarine oyster provides insights into climate impact and adaptive plasticity

Understanding the roles of genetic divergence and phenotypic plasticity in adaptation is central to evolutionary biology and important for assessing adaptive potential of species under climate change. Analysis of a chromosome-level assembly and resequencing of individuals across wide latitude distribution in the estuarine oyster (Crassostrea ariakensis) revealed unexpectedly low genomic diversity and population structures shaped by historical glaciation, geological events and oceanographic forces. Strong selection signals were detected in genes responding to temperature and salinity stress, especially of the expanded solute carrier families, highlighting the importance of gene expansion in environmental adaptation. Genes exhibiting high plasticity showed strong selection in upstream regulatory regions that modulate transcription, indicating selection favoring plasticity. Our findings suggest that genomic variation and population structure in marine bivalves are heavily influenced by climate history and physical forces, and gene expansion and selection may enhance phenotypic plasticity that is critical for the adaptation to rapidly changing environments.

How effective are mobility subsidies in targeting the unemployed? Lessons from the Swedish Model, 1965–1975

The Swedish Model on the labor market has been celebrated as a way to combine mobility with low unemployment and small wage gaps. As part of the model, relocation allowances were pioneered from the late 1950s. The program expanded thereafter and as much as 1% of the population in the high-unemployment north moved with assistance in the 1960s. Today, migration incentives are discussed to address pressing unemployment problems in Europe and the United States. What can Sweden’s experience tell us about the prospects of such programs? This article studies the usage of relocation allowances through a case study of Västernorrland County from 1965 to 1975. The analysis shows that there was a strong selection into the program by younger persons, recent graduates and from sectors with good employment prospects. The experience from Sweden highlights the difficulty of implementing programs to induce migration for those with the highest risk of unemployment.

Why do some primate mothers carry their infant's corpse? A cross-species comparative study

Non-human primates respond to the death of a conspecific in diverse ways, some of which may present phylogenetic continuity with human thanatological responses. Of these responses, infant corpse carrying by mothers (ICC) is the most frequently reported. Despite its prevalence, quantitative analyses of this behaviour are scarce and inconclusive. We compiled a database of 409 published cases across 50 different primate species of mothers' responses to their infants' deaths and used Bayesian phylogenetic regressions with an information-theoretic approach to test hypotheses proposed to explain between- and within-species variation in ICC. We found that ICC was more likely when the infant's death was non-traumatic (e.g. illness) versus traumatic (e.g. infanticide), and when the mother was younger. These results support the death detection hypothesis, which proposes that ICC occurs when there are fewer contextual or sensory cues indicating death. Such an interpretation suggests that primates are able to attain an awareness of death. In addition, when carried, infant age affected ICC duration, with longer ICC observed for younger infants. This result suggests that ICC is a by-product of strong selection on maternal behaviour. The findings are discussed in the context of the evolution of emotion, and implications for evolutionary thanatology are proposed.

Genetic and climatic factors in the dispersal of Anatomically Modern Humans Out of Africa

The evolutionarily recent dispersal of Anatomically Modern Humans (AMH) out of Africa and across Eurasia provides an opportunity to study rapid genetic adaptation to multiple new environments. Genomic analyses of modern human populations have detected limited signals of strong selection such as hard sweeps, but genetic admixture between populations is capable of obscuring these patterns and is well known in recent human history, such as during the Bronze Age4. Here we show that ancient human genomic datasets contain multiple genetic signatures of strong selection including 57 hard sweeps, many with strong associations with cold adaptation. Similar genetic signatures of adaptation are also observed in adaptively-introgressed archaic hominin loci, as well as modern Arctic human groups. Consistent targets include the regulation of fat storage, skin physiology, cilia function and neural development; with multiple associations to modern western diseases. The spatiotemporal patterns of the hard sweeps allow reconstruction of early AMH population dispersals, and reveal a prolonged period of genetic adaptation (~80-50,000 years) following their initial out of Africa movement, before a rapid spread across Eurasia reaching as far as Australia.

COMPARISON OF THE FIRST YEAR LEARNING OUTCOMES OF DUAL AND NONDUAL STUDENTS IN THE LIGHT OF THE INPUT COMPETENCE SURVEY

The number of students taking part in, and the courses involved in dual education have multiplied since the dual education was introduced. At our university, in the last seven years, some hundreds of students have participated in the training based on the German model, implemented in cooperation with partner companies. Based on our assumptions at the beginning of the dual training and the experiences accumulated during the training we assume that in general, more motivated students, the ones who are eager to learn and meet the requirements chose this form of education. The double filter (university and company) makes it possible to choose the best students. The strong selection and the stricter education criteria set by the form of the training (the required progress according to the sample curriculum) results in the students’ achievements which are significantly better than the non-dual students’ results. Thanks to the input surveys regarding the dual and non-dual students which have been conducted since 2010 in our institutions, it is possible to measure the competence of dual and non-dual students at the beginning of the training, and we can also get information about the differences between the two groups and compare the achievements of dual students with the non-dual students. This examination gives a chance to examine how successful the training was for the dual students. The sample of our research consisted of the first year BSc full time students (n = 1,341). We applied the sample adjustment according to the points of the entrance tests when we analysed the achievements of the different training systems. In our presentation, we demonstrate the main areas of the competence survey, the results reached in those areas, the differences between the achievements in those areas, the impact of the input results on the success of learning (the impact of the differences on the results of the first year) in case of dual and non-dual students. We highlight those areas which significantly influence the study results regardless of training forms.

Editorial: “Evolutionary Genetics of Insect Innate Immunity”

The insect innate immune system is under strong selection pressure to evolve resistance to pathogenic infections [...]