SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Ethiopia

38

Although hypoxia is a major stress on physiological processes, several human populations have survived for millennia at high altitudes, suggesting that they have adapted to hypoxic conditions. This hypothesis was recently corroborated by studies of Tibetan highlanders, which showed that polymorphisms in candidate genes show signatures of natural selection as well as well-replicated association signals for variation in hemoglobin levels. We extended genomic analysis to two Ethiopian ethnic groups: Amhara and Oromo. For each ethnic group, we sampled low and high altitude residents, thus allowing genetic and phenotypic comparisons across altitudes and across ethnic groups. Genome-wide SNP genotype data were collected in these samples by using Illumina arrays. We find that variants associated with hemoglobin variation among Tibetans or other variants at the same loci do not influence the trait in Ethiopians. However, in the Amhara, SNP rs10803083 is associated with hemoglobin levels at genome-wide levels of significance. No significant genotype association was observed for oxygen saturation levels in either ethnic group. Approaches based on allele frequency divergence did not detect outliers in candidate hypoxia genes, but the most differentiated variants between high- and lowlanders have a clear role in pathogen defense. Interestingly, a significant excess of allele frequency divergence was consistently detected for genes involved in cell cycle control and DNA damage and repair, thus pointing to new pathways for high altitude adaptations. Finally, a comparison of CpG methylation levels between high- and lowlanders found several significant signals at individual genes in the Oromo.

Concepts: DNA, Gene, Genetics, Natural selection, Genotype, Evolution, Ethiopia, Hypoxia

37

Middle Pliocene hominin species diversity has been a subject of debate over the past two decades, particularly after the naming of Australopithecus bahrelghazali and Kenyanthropus platyops in addition to the well-known species Australopithecus afarensis. Further analyses continue to support the proposal that several hominin species co-existed during this time period. Here we recognize a new hominin species (Australopithecus deyiremeda sp. nov.) from 3.3-3.5-million-year-old deposits in the Woranso-Mille study area, central Afar, Ethiopia. The new species from Woranso-Mille shows that there were at least two contemporaneous hominin species living in the Afar region of Ethiopia between 3.3 and 3.5 million years ago, and further confirms early hominin taxonomic diversity in eastern Africa during the Middle Pliocene epoch. The morphology of Au. deyiremeda also reinforces concerns related to dentognathic (that is, jaws and teeth) homoplasy in Plio-Pleistocene hominins, and shows that some dentognathic features traditionally associated with Paranthropus and Homo appeared in the fossil record earlier than previously thought.

Concepts: Human, Ethiopia, Human evolution, Australopithecus afarensis, Hominina, Australopithecus, Afar Region, Afar Depression

29

Coffee farming provides livelihoods for around 15 million farmers in Ethiopia and generates a quarter of the country’s export earnings. Against a backdrop of rapidly increasing temperatures and decreasing rainfall, there is an urgent need to understand the influence of climate change on coffee production. Using a modelling approach in combination with remote sensing, supported by rigorous ground-truthing, we project changes in suitability for coffee farming under various climate change scenarios, specifically by assessing the exposure of coffee farming to future climatic shifts. We show that 39-59% of the current growing area could experience climatic changes that are large enough to render them unsuitable for coffee farming, in the absence of significant interventions or major influencing factors. Conversely, relocation of coffee areas, in combination with forest conservation or re-establishment, could see at least a fourfold (>400%) increase in suitable coffee farming area. We identify key coffee-growing areas that are susceptible to climate change, as well as those that are climatically resilient.

Concepts: Ethiopia, Precipitation, Climate, Weather, Coffee, Climate change, Solar variation, Thermohaline circulation

28

: Until population-based data become available in Ethiopia, hospital-based studies may reflect the distribution of the subtypes of glaucoma in certain parts of the country.

Concepts: Ethiopia, Distribution of wealth

27

The aim of this study was to characterize Mycobacterium tuberculosis isolates circulating in the Amhara Region of Ethiopia. Sputum samples were collected from new pulmonary tuberculosis (TB) patients in the Region. Genotyping of mycobacterial DNA was performed by spoligotyping and isolates were assigned to families using the SpolDB4 and the model-based program ‘Spotclust’. A high level of diversity was found among the 237 isolates. Sixty-five different spoligopatterns were obtained. The T (30.8%), Central Asian (CAS; 21.1%) and U (17.7%) families were the predominant isolates comprising 69.6% of the total strains. Eighty-five per cent of the U lineage belonged to Spoligo-International-Type (SIT) 910 and SIT 1729. Only a few of these strains are included in SpolDB4 to date. Of the total strains, 41 (17.3%) were unique and have not been described in SpolDB4 to date. This study indicated that the TB epidemic in Amhara Region, Ethiopia, is characterized by the circulation of numerous M. tuberculosis strain families. The high proportion of SIT 910 and SIT 1729 strains may indicate an increase in the importance of these lineages in the transmission of TB in the study region.

Concepts: Ethiopia, Tuberculosis, Mycobacterium, Mycobacterium tuberculosis, Sputum, Robert Koch, Tubercle, Amhara people

27

A study was conducted to isolate bacterial species/pathogens from the nasal cavity of apparently healthy and pneumonic sheep. Nasal swabs were collected aseptically, transported in tryptose soya broth and incubated for 24 h. Then, each swab was streaked onto chocolate and blood agar for culture. Bacterial species were identified following standard bacteriological procedures. Accordingly, a total of 1,556 bacteria were isolated from 960 nasal swabs collected from three different highland areas of Ethiopia, namely Debre Berhan, Asella, and Gimba. In Debre Berhan, 140 Mannheimia haemolytica, 81 Histophilus somni, 57 Staphylococcus species, and 52 Bibersteinia trehalosi were isolated. While from Gimba M. haemolytica, Staphylococcus, Streptococcus, and H. somni were isolated at rates of 25.2, 15.9, 11.4, and 5.9 %, respectively, of the total 647 bacterial species. In Asella from 352 bacterial species isolated, 93 (26.4 %) were M. haemolytica, 48 (13.6 %) were Staphylococcus species, 26 (7.4 %) were B. trehalosi, and 17 (4.8 %) H. somni were recognized. Further identification and characterization using BIOLOG identification system Enterococcus avium and Sphingomonas sanguinis were identified at 100 % probability, while, H. somni and Actinobacillus lignerisii were suggested by the system. The study showed that a variety of bacterial species colonize the nasal cavity of the Ethiopian highland sheep with variable proportion between healthy and pneumonic ones. To our knowledge, this is the first report on isolation of H. somni, an important pathogen in cattle, from the respiratory tract of a ruminant species in the country.

Concepts: Bacteria, Ethiopia, Streptococcus, Staphylococcus, Respiratory system, Enterococcus, Firmicutes, History of Ethiopia

26

Prevention of mother to child HIV transmission (PMTCT) remains a challenge in low and middle-income countries. Determinants of utilization occur - and often interact - at both individual and community levels, but most studies do not address how determinants interact across levels. Multilevel models allow for the importance of both groups and individuals in understanding health outcomes and provide one way to link the traditionally distinct ecological- and individual-level studies. This study examined individual and community level determinants of mother and child receiving PMTCT services in Tigray region, Ethiopia.

Concepts: Ethiopia, Oromo people, Multilevel model, Regions of Ethiopia, Tigray Region, Tigray-Tigrinya people, Agaw

25

Ochre is a common feature at Middle Stone Age (MSA) sites and has often been interpreted as a proxy for the origin of modern behaviour. However, few ochre processing tools, ochre containers, and ochre-stained artefacts from MSA contexts have been studied in detail within a theoretical framework aimed at inferring the technical steps involved in the acquisition, production and use of these artefacts. Here we analyse 21 ochre processing tools, i.e. upper and lower grindstones, and two ochre-stained artefacts from the MSA layers of Porc-Epic Cave, Dire Dawa, Ethiopia, dated to ca. 40 cal kyr BP. These tools, and a large proportion of the 4213 ochre fragments found at the site, were concentrated in an area devoted to ochre processing. Lower grindstones are made of a variety of raw materials, some of which are not locally available. Traces of use indicate that different techniques were employed to process ochre. Optical microscopy, XRD, μ-Raman spectroscopy, and SEM-EDS analyses of residues preserved on worn areas of artefacts show that different types of ferruginous rocks were processed in order to produce ochre powder of different coarseness and shades. A round stone bearing no traces of having been used to process ochre is half covered with residues as if it had been dipped in a liquid ochered medium to paint the object or to use it as a stamp to apply pigment to a soft material. We argue that the ochre reduction sequences identified at Porc-Epic Cave reflect a high degree of behavioural complexity, and represent ochre use, which was probably devoted to a variety of functions.

Concepts: Ethiopia, Dire Dawa, Oromo people, Human behavior, Stone Age, Somalia, Horn of Africa, Harar

24

23

I was volunteering at a refugee centre when a woman told me she was the happiest she could remember being. She said she had previously been a slave, and no matter how bad I thought her situation was now, it was always better than her past.

Concepts: Ethiopia, Woman, Slavery, Slavery in the United States, Atlantic slave trade, Right of asylum, Leo White, Slavery in modern Africa