Time spent together and time spent apart affect song, feather colour and range overlap in tinkerbirds

Abstract Most studies on the processes driving evolutionary diversification highlight the importance of genetic drift in geographical isolation and natural selection across ecological gradients. Direct interactions among related species have received much less attention, but they can lead to character displacement, with recent research identifying patterns of displacement attributed to either ecological or reproductive processes. Together, these processes could explain complex, trait-specific patterns of diversification. Few studies, however, have examined the possible effects of these processes together or compared the divergence in multiple traits between interacting species among contact zones. Here, we show how traits of two Pogoniulus tinkerbird species vary among regions across sub-Saharan Africa. However, in addition to variation between regions consistent with divergence in refugial isolation, both song and morphology diverge between the species where they coexist. In West Africa, where the species are more similar in plumage, there is possible competitive or reproductive exclusion. In Central and East Africa, patterns of variation are consistent with agonistic character displacement. Molecular analyses support the hypothesis that differences in the age of interaction among regions can explain why species have evolved phenotypic differences and coexist in some regions but not others. Our findings suggest that competitive interactions between species and the time spent interacting, in addition to the time spent in refugial isolation, play important roles in explaining patterns of species diversification.

Download Full-text

Adding function to the genome of AfricanSalmonellaST313

10.1101/450098 ◽

2018 ◽

Author(s):

Rocío Canals ◽

Disa L. Hammarlöf ◽

Carsten Kröger ◽

Siân V. Owen ◽

Wai Yee Fong ◽

...

Keyword(s):

Large Scale ◽

Global Gene Expression ◽

Growth Conditions ◽

Trna Synthetase ◽

Sub Saharan Africa ◽

Phenotypic Differences ◽

Metabolic Genes ◽

Lineage 2 ◽

Global Gene Expression Analysis ◽

Sub Saharan

AbstractSalmonellaTyphimurium ST313 causes invasive nontyphoidalSalmonella(iNTS) disease in sub-Saharan Africa, targeting susceptible HIV+, malarial or malnourished individuals. An in-depth genomic comparison between the ST313 isolate D23580, and the well-characterized ST19 isolate 4/74 that causes gastroenteritis across the globe, revealed extensive synteny. To understand how the 856 nucleotide variations generated phenotypic differences, we devised a large-scale experimental approach that involved the global gene expression analysis of strains D23580 and 4/74 grown in sixteen infection-relevant growth conditions. Comparison of transcriptional patterns identified virulence and metabolic genes that were differentially expressed between D23580 versus 4/74, many of which were validated by proteomics. We also uncovered theS.Typhimurium D23580 and 4/74 genes that showed expression differences during infection of murine macrophages. Our comparative transcriptomic data are presented in a new enhanced version of theSalmonellaexpression compendium SalComD23580:bioinf.gen.tcd.ie/cgi-bin/salcom_v2.pl. We discovered that the ablation of melibiose utilization was caused by 3 independent SNP mutations in D23580 that are shared across ST313 lineage 2, suggesting that the ability to catabolise this carbon source has been negatively selected during ST313 evolution. The data revealed a novel plasmid maintenance system involving a plasmid-encoded CysS cysteinyl-tRNA synthetase, highlighting the power of large-scale comparative multi-condition analyses to pinpoint key phenotypic differences between bacterial pathovariants.

Download Full-text

Role of a single noncoding nucleotide in the evolution of an epidemic African clade of Salmonella

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1714718115 ◽

2018 ◽

Vol 115 (11) ◽

pp. E2614-E2623 ◽

Cited By ~ 35

Author(s):

Disa L. Hammarlöf ◽

Carsten Kröger ◽

Siân V. Owen ◽

Rocío Canals ◽

Lizeth Lacharme-Lora ◽

...

Keyword(s):

Gene Expression Signature ◽

Bloodstream Infections ◽

Human Infection ◽

Sub Saharan Africa ◽

Infection Model ◽

Bacterial Survival ◽

Phenotypic Differences ◽

Serovar Typhimurium ◽

Sub Saharan ◽

Transcriptional Start Sites

Salmonella enterica serovar Typhimurium ST313 is a relatively newly emerged sequence type that is causing a devastating epidemic of bloodstream infections across sub-Saharan Africa. Analysis of hundreds of Salmonella genomes has revealed that ST313 is closely related to the ST19 group of S. Typhimurium that cause gastroenteritis across the world. The core genomes of ST313 and ST19 vary by only ∼1,000 SNPs. We hypothesized that the phenotypic differences that distinguish African Salmonella from ST19 are caused by certain SNPs that directly modulate the transcription of virulence genes. Here we identified 3,597 transcriptional start sites of the ST313 strain D23580, and searched for a gene-expression signature linked to pathogenesis of Salmonella. We identified a SNP in the promoter of the pgtE gene that caused high expression of the PgtE virulence factor in African S. Typhimurium, increased the degradation of the factor B component of human complement, contributed to serum resistance, and modulated virulence in the chicken infection model. We propose that high levels of PgtE expression by African S. Typhimurium ST313 promote bacterial survival and dissemination during human infection. Our finding of a functional role for an extragenic SNP shows that approaches used to deduce the evolution of virulence in bacterial pathogens should include a focus on noncoding regions of the genome.

Download Full-text

RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum

Emerging Topics in Life Sciences ◽

10.1042/etls20170101 ◽

2017 ◽

Vol 1 (6) ◽

pp. 533-537

Author(s):

Lorenz von Seidlein ◽

Borimas Hanboonkunupakarn ◽

Podjanee Jittmala ◽

Sasithon Pukrittayakamee

Keyword(s):

Protective Efficacy ◽

Age Groups ◽

Sub Saharan Africa ◽

Phase Iii ◽

European Medicines Agency ◽

Older Children ◽

Pivotal Phase ◽

Malaria Epidemiology ◽

Maximum Benefit ◽

Sub Saharan

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.

Download Full-text

Mortality and Society in Sub-Saharan Africa

Population Studies ◽

10.1080/0032472031000147416 ◽

1993 ◽

Vol 47 (3) ◽

pp. 555-556

Author(s):

Lado Ruzicka

Keyword(s):

Sub Saharan Africa ◽

Sub Saharan

Download Full-text

Sub-Saharan Africa

The Military Balance ◽

10.1080/04597228708459635 ◽

1987 ◽

Vol 87 (1) ◽

pp. 118-142

Keyword(s):

Sub Saharan Africa ◽

Sub Saharan

Download Full-text

Adolescent Suicidality as Seen in Rural Northeastern Uganda

Crisis ◽

10.1027/0227-5910/a000059 ◽

2011 ◽

Vol 32 (1) ◽

pp. 43-51 ◽

Cited By ~ 17

Author(s):

Eugene Kinyanda ◽

Ruth Kizza ◽

Jonathan Levin ◽

Sheila Ndyanabangi ◽

Catherine Abbo

Keyword(s):

Low Socioeconomic Status ◽

Sub Saharan Africa ◽

Psychosocial Risk ◽

Psychiatric Nurses ◽

Health Concern ◽

Cross Sectional ◽

Childhood Experiences ◽

Low Socioeconomic ◽

Dsm Iv ◽

Sub Saharan

Background: Suicidal behavior in adolescence is a public health concern and has serious consequences for adolescents and their families. There is, however, a paucity of data on this subject from sub-Saharan Africa, hence the need for this study. Aims: A cross-sectional multistage survey to investigate adolescent suicidality among other things was undertaken in rural northeastern Uganda. Methods: A structured protocol administered by trained psychiatric nurses collected information on sociodemographics, mental disorders (DSM-IV criteria), and psychological and psychosocial risk factors for children aged 3–19 years (N = 1492). For the purposes of this paper, an analysis of a subsample of adolescents (aged 10–19 years; n = 897) was undertaken. Results: Lifetime suicidality in this study was 6.1% (95% CI, 4.6%–7.9%). Conclusions: Factors significantly associated with suicidality included mental disorder, the ecological factor district of residence, factors suggestive of low socioeconomic status, and disadvantaged childhood experiences.

Download Full-text