Functional genomics in chickens:development of integrated-systems microarrays for transcriptional profiling and discovery of regulatory pathways

The genetic networks that govern the differentiation and growth of major tissues of economic importance in the chicken are largely unknown. Under a functional genomics project, our consortium has generated 30 609 expressed sequence tags (ESTs) and developed several chicken DNA microarrays, which represent the Chicken Metabolic/Somatic (10 K) and Neuroendocrine/Reproductive (8 K) Systems (http://udgenome.ags.udel.edu/cogburn/). One of the major challenges facing functional genomics is the development of mathematical models to reconstruct functional gene networks and regulatory pathways from vast volumes of microarray data. In initial studies with liver-specific microarrays (3.1 K), we have examined gene expression profiles in liver during the peri-hatch transition and during a strong metabolic perturbation—fasting and re-feeding—in divergently selected broiler chickens (fast vs. slow-growth lines). The expression of many genes controlling metabolic pathways is dramatically altered by these perturbations. Our analysis has revealed a large number of clusters of functionally related genes (mainly metabolic enzymes and transcription factors) that control major metabolic pathways. Currently, we are conducting transcriptional profiling studies of multiple tissues during development of two sets of divergently selected broiler chickens (fast vs. slow growing and fat vs. lean lines). Transcriptional profiling across multiple tissues should permit construction of a detailed genetic blueprint that illustrates the developmental events and hierarchy of genes that govern growth and development of chickens. This review will briefly describe the recent acquisition of chicken genomic resources (ESTs and microarrays) and our consortium's efforts to help launch the new era of functional genomics in the chicken

Transcriptional analysis of abdominal fat in chickens divergently selected on bodyweight at two ages reveals novel mechanisms controlling adiposity: validating visceral adipose tissue as a dynamic endocrine and metabolic organ

Decades of intensive genetic selection in the domestic chicken (Gallus gallus domesticus) have enabled the remarkable rapid growth of today’s broiler (meat-type) chickens. However, this enhanced growth rate was accompanied by several unfavorable traits (i.e., increased visceral fatness, leg weakness, and disorders of metabolism and reproduction). The present descriptive analysis of the abdominal fat transcriptome aimed to identify functional genes and biological pathways that likely contribute to an extreme difference in visceral fatness of divergently selected broiler chickens. We used the Del-Mar 14 K Chicken Integrated Systems microarray to take time-course snapshots of global gene transcription in abdominal fat of juvenile [1-11 weeks of age (wk)] chickens divergently selected on bodyweight at two ages (8 and 36 wk). Further, a RNA sequencing analysis was completed on the same abdominal fat samples taken from high-growth (HG) and low-growth (LG) cockerels at 7 wk, the age with the greatest divergence in body weight (3.2-fold) and visceral fatness (19.6-fold). Time-course microarray analysis revealed 312 differentially expressed genes (FDR ≤ 0.05) as the main effect of genotype (HG versus LG), 718 genes in the interaction of age and genotype, and 2918 genes as the main effect of age. The RNA sequencing analysis identified 2410 differentially expressed genes in abdominal fat of HG versus LG chickens at 7 wk. The HG chickens are fatter and over-express numerous genes that support higher rates of visceral adipogenesis and lipogenesis. In abdominal fat of LG chickens, we found higher expression of many genes involved in hemostasis, energy catabolism and endocrine signaling, which likely contribute to their leaner phenotype and slower growth. Many transcription factors and their direct target genes identified in HG and LG chickens could be involved in their divergence in adiposity and growth rate. The present analyses of the visceral fat transcriptome in chickens divergently selected for a large difference in growth rate and abdominal fatness clearly demonstrate that abdominal fat is a very dynamic metabolic and endocrine organ in the chicken. The HG chickens overexpress many transcription factors and their direct target genes, which should enhance in situ lipogenesis and ultimately adiposity. Our observation of enhanced expression of hemostasis and endocrine-signaling genes in diminished abdominal fat of LG cockerels provides insight into genetic mechanisms involved in divergence of abdominal fatness and somatic growth in avian and perhaps mammalian species, including humans.https://doi.org/10.1186/s12864-017-4035-

Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes

BACKGROUND: Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible association between prevalence of adolescent idiopathic scoliosis and age at menarche among normal girls in various geographic latitudes. An attempt is also made to implicate a possible role of melatonin in the above association. MATERIAL-METHODS: 20 peer-reviewed published papers reporting adolescent idiopathic scoliosis prevalence and 33 peer-reviewed papers reporting age at menarche in normal girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included regression of the adolescent idiopathic scoliosis prevalence and age at menarche by latitude. RESULTS: The regression of prevalence of adolescent idiopathic scoliosis and age at menarche by latitude is statistically significant (p < 0.001) and are following a parallel declining course of their regression curves, especially in latitudes northern than 25 degrees. CONCLUSION: Late age at menarche is parallel with higher prevalence of adolescent idiopathic scoliosis. Pubarche appears later in girls that live in northern latitudes and thus prolongs the period of spine vulnerability while other pre-existing or aetiological factors are contributing to the development of adolescent idiopathic scoliosis. A possible role of geography in the pathogenesis of idiopathic scoliosis is discussed, as it appears that latitude which differentiates the sunlight influences melatonin secretion and modifies age at menarche, which is associated to the prevalence of idiopathic scoliosis

Racism as a determinant of health: a systematic review and meta-analysis

Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /

Boosting scientific publications in Africa: which IPRs protection channels matter?

This paper examines how Africa’s share in the contribution to global scientific knowledge can be boosted with existing Intellectual Property Rights (IPRs) mechanisms. The findings which broadly indicate that tight IPRs are correlated with knowledge contribution can be summarized in two main points. First, the enshrinement of IPRs laws in a country’s Constitution is a good condition for knowledge economy. Secondly, while Main IP laws, WIPO treaties and Bilateral treaties are positively correlated with scientific publications, the IPRs law channel have a negative correlation. Whereas the study remains expositional, it does however offer interesting insights into the need for IPRs in the promotion of knowledge contribution within sampled countries of the continent. Other policy implications are discussed

The Role of Lifelong Learning in Political Stability and Non-Violence: Evidence from Africa

Purpose – Education as a weapon in the fight against conflict and violence remains widely debated in policy and academic circles. Against the background of growing political instability in Africa and the central role of the knowledge economy in 21st century development, this paper provides three contributions to existing literature. It assesses how political stability/ non-violence is linked to the incremental, synergy and lifelong learning effects of education. Design/methodology/approach – We define lifelong learning as the combined knowledge acquired during primary, secondary and tertiary education. Principal component analysis is used to reduce the dimensions of educational and political indicators. An endogeneity robust dynamic system Generalized Methods of Moments is used for the estimations. Findings – We establish three main findings. First, education is a useful weapon in the fight against political instability. Second, there is an incremental effect of education in the transition from secondary to tertiary schools. Third, lifelong learning also has positive and synergy effects. This means that the impact of lifelong learning is higher than the combined independent effects of various educational levels. The empirical evidence is based on 53 African countries for the period 1996-2010. Practical implications – A plethora of policy implications are discussed, inter alia: how the drive towards increasing the knowledge economy through lifelong learning can be an effective tool in the fight against violence and political insurgency in Africa. Originality/value – As the continent is nursing knowledge economy ambitions, the paper is original in investigating the determinants of political stability/non violence from three dimensions of education attainment: the incremental, the lifelong learning and a synergy effect

The Comparative Economics of Knowledge Economy in Africa: Policy Benchmarks, Syndromes and Implications

The paper complements the scarce literature on knowledge economy (KE) in Africa by comparing KE dynamics within Africa in order to assess best and worst performers based on fundamental characteristics of the continent’s development. The five dimensions of the World Bank’s knowledge economy index (KEI) are employed, notably: education, information and communication technology, innovation and, economic incentives and institutional regime. The empirical evidence is based on a five-step novel approach with data from 53 African countries for the period 1996-2010. Limitations of the beta catch-up approach are complemented with the sigma convergence strategy. Based on the determined fundamental characteristics, computed dynamic benchmarks, policy syndromes and syndrome free scenarios we establish that: Landlocked, Low-income, Conflict-affected, sub-Saharan African, Non-oil-exporting and French civil law countries are generally more predisposed to lower levels of KE whereas; English common-law, Notlandlocked, Conflict-free, North African and middle-income countries are characteristics that predispose certain nations to higher KE. Broad and specific policy implications are discussed in detail

Globalization, Peace & Stability, Governance, and Knowledge Economy

A previous analysis of the impact of formal institutions on the knowledge economy of 22 Middle-Eastern and Sub-Sahara African countries during the 1996-2010 time period concluded that formal institutions were necessary, but inadequate, determinants of the knowledge economy. To extend that study, this paper claims that globalization induces peace and stability, which affects governance and through governance the knowledge economy. The claim addresses one weakness of previous research that did not consider the effects on the knowledge economy of globalization. We model the proposition as a three-stage process in four hypotheses, and estimate each hypothesis using robust estimators that are capable of dealing with the usual statistical problems without sacrificing economic relevance and significance. The results indicate that globalization has varying effects on peace and stability, and peace and stability affect governance differently depending on what kind of globalization induces it. For instance, the effects on governance induced by globalization defined as trade are stronger than those resulting from globalization taken to be foreign direct investment. Hence, we conclude that foreign direct investment is not a powerful mechanism for stimulating and sustaining the knowledge economy in our sample of countries. However, since globalization-induced peace and stability have both positive and negative effects on governance simultaneously, we also conclude that while the prospect for knowledge economy in African countries is dim, it is still realistic and attainable as long as these countries continue to engage in the kind of globalization that does indeed induce peace and stability. We further conclude that there is a need for a sharper focus on economic and institutional governance than on general governance as one possible extension of this paper

Trajectories in Knowledge Economy: Empirics from SSA and MENA countries

In the first critical assessment of knowledge economy dynamic paths in Africa and the Middle East, but for a few exceptions, we find overwhelming support for diminishing cross-country disparities in knowledge-base-economy dimensions. The paper employs all the four components of the World Bank’s Knowledge Economy Index (KEI): economic incentives, innovation, education, and information infrastructure. The main finding suggests that sub-Saharan African (SSA) and the Middle East and North African (MENA) countries with low levels in KE dynamics and catching-up their counterparts of higher KE levels. We provide the speeds of integration and time necessary to achieve full (100%) integration. Policy implications are discussed