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The origin of eukaryotic cells, and especially naturally occurring syncytial cells, remains debatable. While a majority of our biomedical research focuses on the eukaryotic result of evolution, our data remain limiting on the prokaryotic precursors of these cells. This is particularly evident when considering extremophile biology, especially in how the genomes of organisms in extreme environments must have evolved and adapted to unique habitats. Might these rapidly diversifying organisms have created new genetic tools eventually used to enhance the evolution of the eukaryotic single nuclear or syncytial cells? Many organisms are capable of surviving, or even thriving, in conditions of extreme temperature, acidity, organic composition, and then rapidly adapt to yet new conditions. This study identified organisms found in extremes of salinity. A lake and a nearby pond in the Ethiopian Rift Valley were interrogated for life by sequencing the DNA of populations of organism collected from the water in these sites. Remarkably, a vast diversity of microbes were identified, and even though the two sites were nearby each other, the populations of organisms were distinctly different. Since these microbes are capable of living in what for humans would be inhospitable conditions, the DNA sequences identified should inform the next step in these investigations; what new gene families, or modifications to common genes, do these organisms employ to survive in these extreme conditions. The relationship between organisms and their environment can be revealed by decoding genomes of organisms living in extreme environments. These genomes disclose new biological mechanisms that enable life outside moderate environmental conditions, new gene functions for application in biotechnology, and may even result in identification of new species. In this study, we have collected samples from two hypersaline sites in the Danakil depression, the shorelines of Lake As'ale and an actively mixing salt pond called Muda'ara (MUP), to identify the microbial community by metagenomics. Shotgun sequencing was applied to high density sampling, and the relative abundance of Operational Taxonomic Units (OTUs) was calculated. Despite the broad taxonomic similarities among the salt-saturated metagenomes analyzed, MUP stood out from Lake As'ale samples. In each sample site, Archaea accounted for 95% of the total OTUs, largely to the class Halobacteria. The remaining 5% of organisms were eubacteria, with an unclassified strain of Salinibacter ruber as the dominant OTU in both the Lake and the Pond. More than 40 different genes coding for stress proteins were identified in the three sample sites of Lake As'ale, and more than 50% of the predicted stress-related genes were associated with oxidative stress response proteins. Chaperone proteins (DnaK, DnaJ, GrpE, and ClpB) were predicted, with percentage of query coverage and similarities ranging between 9.5% and 99.2%. Long reads for ClpB homologous protein from Lake As'ale metagenome datasets were modeled, and compact 3D structures were generated. Considering the extreme environmental conditions of the Danakil depression, this metagenomics dataset can add and complement other studies on unique gene functions on stress response mechanisms of thriving bio-communities that could have contributed to cellular changes leading to single and/or multinucleated eukaryotic cells., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

In the semiarid Bulal transboundary catchment of southern Ethiopia, groundwater is the only reliable drought-resilient water source. The central and southern parts of the catchment are dominantly overlain by the transboundary aquifers of the Bulal basalts, while the basement rocks outcrop in the eastern part. This study uses an integrated geographic information system (GIS), remote sensing (RS), and analytical hierarchal process (AHP) to identify and delineate the groundwater potential zones of the semiarid Bulal catchment within the Ethiopian territory. Based on their relative importance to groundwater occurrence and movement, ten input parameters were chosen. According to Saaty's AHP approach, the input themes and each of their distinct features were given normalized weights. A composite groundwater potential zone index (GWPZI) map was generated by integrating all the input layers employing the GIS-overlay analysis technique. The map was validated using the yield of wells from the catchment. The GWPZI map depicts four groundwater potential zones: high (representing 27% of the total area), moderate (20%), low (28%), and very low (25%). The geological feature has the greatest influence on the distribution of groundwater potential. Areas with high potential are mainly overlain by the Bulal basaltic flow, while low groundwater potential zones are in the regolith over the basement rocks. Unlike conventional methods, our novel approach is effective in identifying relatively shallow GWPZs throughout the catchment, and it can be applied in similar semiarid regions. The GWPZI map serves as a quick guide for effectively planning, managing, and developing the catchment's groundwater resources., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (~275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (~60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens ., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2022.)

Efforts to date the oldest modern human fossils in eastern Africa, from Omo-Kibish 1-3 and Herto 4,5 in Ethiopia, have drawn on a variety of chronometric evidence, including 40 Ar/ 39 Ar ages of stratigraphically associated tuffs. The ages that are generally reported for these fossils are around 197 thousand years (kyr) for the Kibish Omo I 3,6,7 , and around 160-155 kyr for the Herto hominins 5,8 . However, the stratigraphic relationships and tephra correlations that underpin these estimates have been challenged 6,8 . Here we report geochemical analyses that link the Kamoya's Hominid Site (KHS) Tuff 9 , which conclusively overlies the member of the Omo-Kibish Formation that contains Omo I, with a major explosive eruption of Shala volcano in the Main Ethiopian Rift. By dating the proximal deposits of this eruption, we obtain a new minimum age for the Omo fossils of 233 ± 22 kyr. Contrary to previous arguments 6,8 , we also show that the KHS Tuff does not correlate with another widespread tephra layer, the Waidedo Vitric Tuff, and therefore cannot anchor a minimum age for the Herto fossils. Shifting the age of the oldest known Homo sapiens fossils in eastern Africa to before around 200 thousand years ago is consistent with independent evidence for greater antiquity of the modern human lineage 10 ., (© 2022. The Author(s).)

The acid ponds of the Danakil Depression in northern Ethiopia are polyextreme environments that exceed the normal physicochemical limits of pH, salinity, ion content, and temperature. We tested for the occurrence of DNA-based life in this environment using Metagenomic Shotgun DNA sequencing approaches. The obtained sequences were examined by the bioinformatic tools MetaSpades, DIAMOND and MEGAN 6-CE, and we were able to bin more than 90% of the metagenomics contigs of Dallol and Black Water to the Bacteria domain, and to the Proteobacteria phylum. Predictions of gene function based on SEED disclosed the presence of different nutrient cycles in the acid ponds. For this study, we focused on partial or completely sequenced genes involved in nitrogen metabolism. The KEGG nitrogen metabolism pathway mapping results for both acid ponds showed that all the predicted genes are involved directly or indirectly in the assimilation of ammonia and no dissimilation or nitrification process was identified. Furthermore, the deduced nitrogen fixation in the two acid ponds based on SEED classification indicated the presence of different sets of nitrogen fixing (nif) genes for biosynthesis and maturation of nitrogenase. Based on the in silico analysis, the predicted proteins involved in nitrogen fixation, especially the cysteine desulfurase and [4Fe-4S] ferredoxin, from both acid ponds are unique with less than 80% sequence similarity to the next closest protein sequence. Considering the extremity of the environmental conditions of the two acid ponds in the Danakil depression, this metagenomics dataset can add to the study of unique gene functions in nitrogen metabolism that enable thriving biocommunities in hypersaline and highly acidic conditions.