Biology subjects

Kebede, A.

Publications and source records attributed to Kebede, A..

6 recordsLinked to original sources

bioRxiv2025

The influence of Temperature and Relative Humidity on the Development and Survival of Laboratory-Reared Anopheles arabiensis in Ethiopia

Malaria, a major vector-borne disease transmitted by female Anopheles mosquitoes, remains a critical public health challenge in tropical and subtropical regions. Climate change influences vector distribution, abundance, and disease transmission patterns. This study examined the influence of temperature and humidity on the development, abundance, and survival of Anopheles arabiensis, a key malaria vector in Ethiopia. Laboratory reared susceptible An. arabiensis strain mosquitoes were reared under varying conditions, with 400 eggs exposed to temperatures of 14.5-34.35{degrees}C and relative humidity (RH) levels of 64-84% and compared with the ones that reared under standard insectary conditions. Development and survival rates were analyzed across 20 temperature-humidity regimes using SPSS 26, with linear regression, OLS, and quadratic regression models. Results showed optimal egg hatchability (80%) at 25.3-34.35{degrees}C and 64-68% RH. Adult emergence peaked (80%) at 28.37-29.65{degrees}C and 70% RH, but declined significantly below 16{degrees}C and 64% RH. The longest larval development (13 days) occurred at 14.55-15.62{degrees}C and 83-86% RH, while adult survival reached 25 days at 23.65-24.72{degrees}C and 68-69% RH. These findings highlight the profound influence of temperature and humidity on An. arabiensis life stages, emphasizing their role in mosquito population dynamics. Further research is needed to explore how these factors affect malaria parasite development within vectors, offering insights to improve malaria control strategies.

ecology↗

bioRxiv2023

Altitude-dependent agro-ecologies impact the microbiome diversity of scavenging indigenous chicken in Ethiopia

Scavenging indigenous village chickens play a vital role in sub-Saharan Africa, sustaining the livelihood of millions of farmers. These chickens are exposed to vastly different environments and feeds compared to commercial chickens. In this study, we analysed the caecal microbiota of 243 Ethiopian village chickens living in different altitude-dependent agro-ecologies. Differences in bacterial diversity were significantly correlated with differences in specific climate factors, topsoil characteristics, and supplemental diets provided by farmers. Microbiota clustered into 3 enterotypes, with one particularly enriched at high altitudes. We assembled 9,977 taxonomically and functionally diverse metagenome-assembled genomes, the vast majority of which were not found in a dataset of previously published chicken microbes, or in the Genome Taxonomy Database. The wide functional and taxonomic diversity of these microbes highlights their importance in the local adaptation of indigenous poultry, and the significant impacts of environmental factors on the microbiota argues for further discoveries in other agro-ecologies.

microbiology↗

bioRxiv2021

A framework for defining livestock ecotypes based on ecological modelling and exploring genomic environmental adaptation: the example of Ethiopian village chicken

In evolutionary ecology, an ecotype is a population that is genetically adapted to specific environmental conditions. Environmental and genetic characterisation of livestock ecotypes can play a crucial role in conservation and breeding improvement, particularly to achieve climate resilience. However, livestock ecotypes are often arbitrarily defined without a detailed characterisation of their agro-ecologies. In this study, we employ a novel integrated approach, combining Ecological Niche Modelling (ENM) with genomics, to delineate ecotypes based on environmental characterisation of population habitats and unravel the signatures of adaptive selection in the ecotype genomes. The method was applied on 25 Ethiopian village chicken populations representing diverse agro-climatic conditions. ENM identified six key environmental drivers of adaptation and delineated 12 ecotypes. Within- ecotype selection signature analyses (using Hp and iHS methods) identified 1,056 candidate sweep regions (SRs) associated with diverse biological processes. A few biological pathways were shared amongst most ecotypes and the involved genes showed functions important for scavenging chickens, e.g. neuronal development/processes, immune response, vision development, and learning. Genotype-environment association using Redundancy Analysis (RDA) allowed for correlating [~]33% of the SRs with major environmental drivers. Inspection of some strong candidate genes from selection signature analysis and RDA showed highly relevant functions in relation to the major environmental drivers of corresponding ecotypes. This integrated approach offers a powerful tool to gain insight into the complex processes of adaptive evolution including the genotype x environment (GxE) interactions.

genetics↗

bioRxiv2021

The natural adaptation and human selection history of African sheep genomes

African sheep manifest diverse but distinct physio-anatomical traits which are the outcomes of natural- and human-driven selection. Here, we generated 34.8 million variants from 150 indigenous African sheep genomes sequenced at an average depth of [~]54x for 130 samples (Ethiopia, Libya) and [~]10x for 20 samples (Sudan), representing sheep from diverse environments, tail morphology and post-Neolithic introductions to Africa. Phylogenetic and model-based admixture analysis provided evidence of four genetic groups that correspond to altitudinal geographic origins and tail morphotypes. Comparative genomic analysis identified targets of selection spanning conserved haplotype structures overlapping genes and gene families relating to hypoxia responses, caudal vertebrae and tail skeleton length, ear morphology, and tail fat-depot structure. Our findings provide novel insights underpinning variation and response to human selection and environmental adaptation, and possible pleiotropic gene interactions in indigenous African sheep genomes, which guaranteed the successful establishment of the species on the continent.

genomics↗

bioRxiv2020

Integrated environmental and genomic analysis reveals the drivers of local adaptation in African indigenous chickens

Elucidating the genetic basis of environmental adaptation in indigenous livestock populations has important implications for sustainable breeding improvement. It requires a detailed untangling of relevant environmental pressures and fine resolution detection of genomic signatures of selection associated with these environmental parameters. Here, we uniquely employed an integrative approach, combining Ecological Niche Modelling (ENM) with (i) genome-wide analyses of positive signatures of selection (SSA) and (ii) genotype-environment association (GEA) analyses to unravel the environmental adaptation of Ethiopian indigenous chickens. We first examined 34 agro-ecological and climatic variables and identified six main environmental selection drivers (one temperature - strongly correlated to elevation, three precipitation, and two soil/land variables). We then performed genomic analyses using high-density SNP data from whole-genome sequencing of 245 Ethiopian chickens from 25 different populations. Environmental genomic association analyses (SSA and GEA) identify a few strongly supported selected genomic regions, often with clusters of candidate genes, related to altitude-induced stresses (hypoxia, thrombosis, and cold temperatures), water scarcity, and the challenges of scavenging feeding behaviour. These analyses support a predominantly oligogenic control of environmental adaptation and possible regulation by one or few genetic elements only. Our study shows that the pre-identification of the key environmental drivers of adaptation, followed by a detailed genomic investigation of the associated genetic mechanisms provides a powerful new approach for elucidating the effect of natural selection in domestic animals. These results represent new landmarks to inform sustainable poultry breeding improvement.

genomics↗

bioRxiv2019

Diversified Diet Feeding Practice is Low Compared to the WHO Recommendation in the Dabat Demographic and Health Surveillance System Site: Finding from the Baseline Survey of Nutrition Project, 2016

IntroductionImproving infant and young child feeding practices is critical to improved nutrition, health, and development of children. The country of Ethiopia has also adopted the WHO recommendations of child feeding practices and developed the national guideline of infant and young child feeding to improve childs nutrition and health status. However, a few children start and received appropriate complementary feeding based on the recommendation. Therefore, the study aimed to determine dietary diversity score and its associated factors among under five children at Dabat Demography Surveillance System site (HDSS), northwest Ethiopia. MethodsA cross-sectional community based study was from February to June 2016. All children aged 6-59 months old who lived in HDSS site were included in the survey. The collected data were checked and entered into Epi info version 7 and exported to STATA version 14 statistical software for analysis. Both crude odds ratio (COR) and adjusted odds ratio (AOR) with the corresponding 95% confidence interval (CI) was calculated to show the strength of association. Finally, a p-value of 0.05 was used to determine if the association was statistically significant. ResultsIn this study, about 34.87% (95%CI: 33.27, 36.49%) of the children received adequately diversified diet. The odds of receiving adequately diversified diet was higher among children whose mother had secondary and above education (AOR= 6.51; 95%CI: 4.95, 8.56), mother who had ANC (AOR = 1.90; 95%CI: 1.60, 2.26) and PNC visit (AOR= 1.31; 95%CI: 1.00, 1, 72). However, a lower dietary diversity score is observed among young children (AOR=0.59; 95%CI: 0.41, 0.85), and children from food inscured household (AOR=0.76; 95%CI: 0.63, 0.92). ConclusionsDiversified diet feeding practice is low compared to the WHO recommendation in the surveillance site. Age of the child, maternal education, ANC and PNC visit, and household food insecurity were significantly associated with Dietary diversity score of children. Hence, various actions need to scale up the current practices of child feeding by improving HHFSS, strengthening ANC and PNC counselling about child feeding options, and feeding of young infants.

epidemiology↗