Publications by authors named "Asilatu Shechonge"
Article Synopsis
- Cichlid fishes of the genus Oreochromis, or tilapia, are crucial for inland fisheries and aquaculture, but hybridization with non-native species threatens local biodiversity.
- Researchers studied hybridization patterns in tilapia by analyzing the genomes of 575 individuals from 23 species in Tanzania, where both ancient and recent hybridization occurs.
- Their findings reveal significant historical gene flow and the hybrid speciation of a specific species, highlighting concerns for conservation and the future of aquaculture practices.
Article Synopsis
- Researchers investigated how nuclear genetic material from environmental DNA (eDNA) can reveal population genetics of cichlid fish in Lake Masoko, Tanzania.
- * The study focused on two genetically distinct ecomorphs of cichlids separated by a thermo-oxycline at 15 meters depth, indicating diverging populations within the lake.
- * By analyzing single nucleotide polymorphisms (SNPs) from both eDNA and fish samples, the team confirmed that eDNA can accurately reflect the genetic structure of populations across different depths in the lake.
Article Synopsis
- Freshwater fishes, like the cichlid Astatotilapia calliptera in Lake Masoko, have undergone rapid speciation along depth gradients, with distinct ecomorphs developing in just 1,000 years.
- Researchers used genome-wide transcriptome data to analyze the molecular mechanisms behind these changes, specifically focusing on gene expression and splicing variations.
- They discovered thousands of differently expressed genes, with certain regulatory variants significantly influencing craniofacial development, indicating that modifications in gene regulation are key to early-stage speciation and adaptive divergence.
Article Synopsis
- - Epigenetic variation can influence gene expression and lead to differences in traits among populations adapting to different environments, specifically in the early stages of speciation.
- - The research examines the DNA methylome changes in two morphologically and ecologically distinct ecomorphs of Astatotilapia calliptera in Africa's Lake Masoko, which evolved about 1,000 years ago, despite no fixed genetic differences.
- - Findings show extensive differences in methylation patterns related to critical biological functions, supporting the idea that epigenetics plays a role in early vertebrate speciation, with some traits being inherited across generations.
Article Synopsis
- - Cichlid fish are vital for tilapia aquaculture and fisheries, but distinguishing between species is challenging due to morphological similarities and hybridization with non-native populations in Africa.
- - A new genotyping panel using SNPs has been developed to accurately identify species and hybrids in tilapia, proving to be more effective than traditional methods like microsatellites and phenotype classification.
- - Case studies reveal that introduced tilapia species are increasingly becoming established in the wild, posing risks to native species, highlighting the need for better broodstock management to conserve biodiversity.
Tetrapods and fish have adapted distinct carbamoyl-phosphate synthase (CPS) enzymes to initiate the ornithine urea cycle during the detoxification of nitrogenous wastes. We report evidence that in the ureotelic subgenus of extremophile fish , CPS III has undergone convergent evolution and adapted its substrate affinity to ammonia, which is typical of terrestrial vertebrate CPS I. Unusually, unlike in other vertebrates, the expression of CPS III in is localized to the skeletal muscle and is activated in the myogenic lineage during early embryonic development with expression remaining in mature fish.
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- Invasive Nile tilapia are hybridizing with native Korogwe tilapia in southern Tanzania, threatening unique genetic resources.
- Research shows that southern Korogwe tilapia populations are genetically distinct from those in northern Tanzania, having diverged around 140,000 years ago.
- Findings indicate the need for conservation efforts to protect these unique and vulnerable fish populations from hybridization and genetic dilution.
Article Synopsis
- The study explores cardiac development in a non-model fish species, revealing gene expression patterns that are similar to well-known vertebrate models but also distinct in certain aspects.
- Researchers observed significant vascularization in the fish's yolk prior to hatching and identified key cardiac transcription factors that are involved in other developmental processes like blood, limbs, and muscle formation.
- The findings suggest that this fish exhibits conserved molecular mechanisms of development, which may provide insights into how species adapt to extreme environmental conditions, especially in light of climate change.
Article Synopsis
- The correction addresses errors found in the original publication of the article.
- It clarifies specific data points or findings that were inaccurately presented.
- This is important for maintaining the integrity and accuracy of the research findings in the field.
Article Synopsis
- Schistosomiasis is a serious tropical disease caused by parasitic worms, and new diagnostic methods are needed to detect these parasites in the environment.
- Researchers developed qPCR assays to specifically identify the species Schistosoma mansoni, S. haematobium, and S. japonicum with high accuracy, despite some cross-reactivity issues.
- The use of environmental DNA (eDNA) proved effective in confirming the presence of these parasites in various freshwater sites, suggesting that eDNA monitoring could enhance disease control efforts.
Article Synopsis
- Schistosomiasis affects over 200 million people globally, and improved surveillance methods using environmental DNA (eDNA) could enhance control measures for this neglected tropical disease.
- A new xenomonitoring method was developed to detect schistosome infections in host snails by analyzing eDNA from water they are housed in, improving accuracy even when schistosome eDNA is rare in the environment.
- The results showed that this eDNA-based approach reliably identified S. mansoni infections in all tests and S. haematobium in 92% of tests, suggesting it could be a valuable tool for monitoring infections and guiding interventions in areas where schistosomiasis is endemic.
Article Synopsis
- Cichlids have diversified significantly across Africa, particularly in rivers and lakes, with a focus on the economically important oreochromine cichlids, or tilapia, which have unique adaptations to soda environments.
- This study presents a comprehensive DNA analysis of the Oreochromis genus and closely related Alcolapia, revealing discordance between nuclear and mitochondrial DNA, which may suggest complex evolutionary histories.
- The research indicates that adaptation to harsh conditions has occurred multiple times in Oreochromis, with extreme adaptations likely originating once, leading to a taxonomic revision that places Alcolapia as a subgenus of Oreochromis.
Hybridization between introduced and indigenous species can lead to loss of unique genetic resources and precipitate extinction. In Tanzania, the Nile tilapia () and blue-spotted tilapia () have been widely introduced to non-native habitats for aquaculture and development of capture fisheries. Here, we aimed to quantify interspecific hybridization between these introduced species and the indigenous species , and .
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- From the 1950s, East Africa has implemented aquaculture and fisheries programs focused on introduced species, though documentation in Tanzania has been lacking.
- A study conducted between 2011 and 2017 identified tilapia species across 123 locations, revealing 14 native taxa and three species, including one exotic (blue-spotted tilapia) that have expanded their range.
- Habitat modeling suggests that suitable conditions for these introduced species will persist and possibly expand due to changing climate projections, aiding in biodiversity management and informing future policies on aquaculture.
Article Synopsis
- Hybridization between invasive tilapia species and indigenous Wami tilapia in Tanzania poses significant genetic and morphological risks, as indicated by studies conducted at Mindu Reservoir and Kidatu.
- The research utilized genetic screening and morphological assessments and found hybrids displaying a diverse range of physical traits that overlap with both parent species.
- The findings suggest that the introduction of invasive tilapia has greatly affected the gene pool and traits of indigenous tilapia populations, leading to recommendations for caution in further invasive species introductions, especially when no clear benefits exist.