Browsing by Author "Schmidt, Carl J"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
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 Heat Stress and Lipopolysaccharide Stimulation of Chicken Macrophage-Like Cell Line Activates Expression of Distinct Sets of Genes(Public Library Science, 10/13/16) Slawinska,Anna; Hsieh,John C.; Schmidt,Carl J.; Lamont,Susan J.; Anna Slawinska, John C. Hsieh, Carl J. Schmidt, Susan J. Lamont; Schmidt, Carl JAcute heat stress requires immediate adjustment of the stressed individual to sudden changes of ambient temperatures. Chickens are particularly sensitive to heat stress due to Developmentelopment of insufficient physiological mechanisms to mitigate its effects. One of the symptoms of heat stress is endotoxemia that results from release of the lipopolysaccharide (LPS) from the guts. Heat-related cytotoxicity is mitigated by the innate immune system, which is comprised mostly of phagocytic cells such as monocytes and macrophages. The objective of this study was to analyze the molecular responses of the chicken macrophage-like HD11 cell line to combined heat stress and lipopolysaccharide treatment in vitro. The cells were heat-stressed and then allowed a temperature-recovery period, during which the gene expression was investigated. LPS was added to the cells to mimic the heat-stress-related endotoxemia. Semi high-throughput gene expression analysis was used to study a gene panel comprised of heat shock proteins, stress-related genes, signaling molecules and immune response genes. HD11 cell line responded to heat stress with increased mRNA abundance of the HSP25, HSPA2 and HSPH1 chaperones as well as DNAJA4 and DNAJB6 co-chaperones. The anti-apoptotic gene BAG3 was also highly up-regulated, providing evidence that the cells expressed pro-survival processes. The immune response of the HD11 cell line to LPS in the heat stress environment (up-regulation of CCL4, CCL5, IL1B, IL8 and iNOS) was higher than in thermoneutral conditions. However, the peak in the transcriptional regulation of the immune genes was after two hours of temperature-recovery. Therefore, we propose the potential influence of the extracellular heat shock proteins not only in mitigating effects of abiotic stress but also in triggering the higher level of the immune responses. Finally, use of correlation networks for the data analysis aided in discovering subtle differences in the gene expression (i.e. the role of the CASP3 and CASP9 genes).Item Quantitative trait loci identified for blood chemistry components of an advanced intercross line of chickens under heat stress(Biomed Central Ltd, 4/14/16) Van Goor,Angelica; Ashwell,Christopher M.; Persia,Michael E.; Rothschild,Max F.; Schmidt,Carl J.; Lamont,Susan J.; Angelica Van Goor, Christopher M. Ashwell, Michael E. Persia, Max F. Rothschild, Carl J. Schmidt and Susan J. Lamont; Schmidt, Carl JBackground: Heat stress in poultry results in considerable economic losses and is a concern for both animal health and welfare. Physiological changes occur during periods of heat stress, including changes in blood chemistry components. A highly advanced intercross line, created from a broiler (heat susceptible) by Fayoumi (heat resistant) cross, was exposed to daily heat cycles for seven days starting at 22 days of age. Blood components measured pre-heat treatment and on the seventh day of heat treatment included pH, pCO(2), pO(2), base excess, HCO3, TCO2, K, Na, ionized Ca, hematocrit, hemoglobin, sO(2), and glucose. A genome-wide association study (GWAS) for these traits and their calculated changes was conducted to identify quantitative trait loci (QTL) using a 600 K SNP panel. Results: There were significant increases in pH, base excess, HCO3, TCO2, ionized Ca, hematocrit, hemoglobin, and sO(2), and significant decreases in pCO(2) and glucose after 7 days of heat treatment. Heritabilities ranged from 0.01-0.21 for pre-heat measurements, 0.01-0.23 for measurements taken during heat, and 0.00-0.10 for the calculated change due to heat treatment. All blood components were highly correlated within measurement days, but not correlated between measurement days. The GWAS revealed 61 QTL for all traits, located on GGA (Gallus gallus chromosome) 1, 3, 6, 9, 10, 12-14, 17, 18, 21-28, and Z. A functional analysis of the genes in these QTL regions identified the Angiopoietin pathway as significant. The QTL that co-localized for three or more traits were on GGA10, 22, 26, 28, and Z and revealed candidate genes for birds' response to heat stress. Conclusions: The results of this study contribute to our knowledge of levels and heritabilities of several blood components of chickens under thermoneutral and heat stress conditions. Most components responded to heat treatment. Mapped QTL may serve as markers for genomic selection to enhance heat tolerance in poultry. The Angiopoietin pathway is likely involved in the response to heat stress in chickens. Several candidate genes were identified, giving additional insight into potential mechanisms of physiologic response to high ambient temperatures.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.