Browsing by Author "Ashwell,C. M."
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Item Genomic analysis of Ugandan and Rwandan chicken ecotypes using a 600 k genotyping array(Biomed Central Ltd, 5/26/16) Fleming,D. S.; Koltes,J. E.; Markey,A. D.; Schmidt,C. J.; Ashwell,C. M.; Rothschild,M. F.; Persia,M. E.; Reecy,J. M.; Lamont,S. J.; D. S. Fleming, J. E. Koltes, A. D. Markey, C. J. Schmidt, C. M. Ashwell, M. F. Rothschild, M. E. Persia, J. M. Reecy and S. J. Lamont; Schmidt, Carl JBackground: Indigenous populations of animals have Developmenteloped unique adaptations to their local environments, which may include factors such as response to thermal stress, drought, pathogens and suboptimal nutrition. The survival and subsequent evolution within these local environments can be the result of both natural and artificial selection driving the acquisition of favorable traits, which over time leave genomic signatures in a population. This study's goals are to characterize genomic diversity and identify selection signatures in chickens from equatorial Africa to identify genomic regions that may confer adaptive advantages of these ecotypes to their environments. Results: Indigenous chickens from Uganda (n = 72) and Rwanda (n = 100), plus Kuroilers (n = 24, an Indian breed imported to Africa), were genotyped using the Axiom (R) 600 k Chicken Genotyping Array. Indigenous ecotypes were defined based upon location of sampling within Africa. The results revealed the presence of admixture among the Ugandan, Rwandan, and Kuroiler populations. Genes within runs of homozygosity consensus regions are linked to gene ontology (GO) terms related to lipid metabolism, immune functions and stress-mediated responses (FDR < 0. 15). The genes within regions of signatures of selection are enriched for GO terms related to health and oxidative stress processes. Key genes in these regions had anti-oxidant, apoptosis, and inflammation functions. Conclusions: The study suggests that these populations have alleles under selective pressure from their environment, which may aid in adaptation to harsh environments. The correspondence in gene ontology terms connected to stress-mediated processes across the populations could be related to the similarity of environments or an artifact of the detected admixture.Item Single nucleotide variant discovery of highly inbred Leghorn and Fayoumi chicken breeds using pooled whole genome resequencing data reveals insights into phenotype differences(Biomed Central Ltd, 10/19/16) Fleming,D. S.; Koltes,J. E.; Fritz-Waters,E. R.; Rothschild,M. F.; Schmidt,C. J.; Ashwell,C. M.; Persia,M. E.; Reecy,J. M.; Lamont,S. J.; D. S. Fleming, J. E. Koltes, E. R. Fritz-Waters, M. F. Rothschild, C. J. Schmidt, C. M. Ashwell, M. E. Persia, J. M. Reecy and S. J. Lamont; Schmidt, Carl JBackground: Analyses of sequence variants of two distinct and highly inbred chicken lines allowed characterization of genomic variation that may be associated with phenotypic differences between breeds. These lines were the Leghorn, the major contributing breed to commercial white-egg production lines, and the Fayoumi, representative of an outbred indigenous and robust breed. Unique within-and between-line genetic diversity was used to define the genetic differences of the two breeds through the use of variant discovery and functional annotation. Results: Downstream fixation test (FST) analysis and subsequent gene ontology (GO) enrichment analysis elucidated major differences between the two lines. The genes with high FST values for both breeds were used to identify enriched gene ontology terms. Over-enriched GO annotations were uncovered for functions indicative of breed-related traits of pathogen resistance and reproductive ability for Fayoumi and Leghorn, respectively. Conclusions: Variant analysis elucidated GO functions indicative of breed-predominant phenotypes related to genomic variation in the lines, showing a possible link between the genetic variants and breed traits.