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Understanding and predicting the relationships between genotype and phenotype is often challenging, largely due to the complex nature of eukaryotic gene regulation. A step towards this goal is to map how phenotypic diversity evolves through genomic changes that modify gene regulatory interactions. Using the Prairie Rattlesnake (Crotalus viridis) and related species, we integrate mRNA-seq, proteomic, ATAC-seq and whole-genome resequencing data to understand how specific evolutionary modifications to gene regulatory network components produce differences in venom gene expression. Through comparisons within and between species, we find a remarkably high degree of gene expression and regulatory network variation across even a shallow level of evolutionary divergence. We use these data to test hypotheses about the roles of specific trans-factors and cis-regulatory elements, how these roles may vary across venom genes and gene families, and how variation in regulatory systems drive diversity in venom phenotypes. Our results illustrate that differences in chromatin and genotype at regulatory elements play major roles in modulating expression. However, we also find that enhancer deletions, differences in transcription factor expression, and variation in activity of the insulator protein CTCF also likely impact venom phenotypes. Our findings provide insight into the diversity and gene-specificity of gene regulatory features and highlight the value of comparative studies to link gene regulatory network variation to phenotypic variation. [ABSTRACT FROM AUTHOR]

Tri-axial accelerometers (ACTs) are becoming increasingly common in studies of animal behavior wherein direct observation of subjects in nature is constrained or impossible. ACTs are small (< 1 g) piezo-electric (spring-like) sensors that measure three-dimensional acceleration (upward, downward, and side-to-side) derived from subject motion. When leveraged with advanced machine learning techniques, these data can enable precise automated classification of a wide range of movement-mediated behaviors. Until recently, ACTs were largely reserved for larger-bodied organisms or those most amenable to the temporary external attachment of devices. Ongoing ACT miniaturization has now expanded the breadth of organisms amenable to these methods. This project aims to expand on a recently developed framework for ACT monitoring in wild-ranging snakes, a group that has been mostly overlooked in biologging applications. We have completed extensive captive ACT validation trials with timber rattlesnakes (Crotalus horridus) and have used these datasets in the training and testing of robust classification models of foraging behaviors, i.e. strike and swallowing of prey items. Using AcceleRater, a free online service available to the community, we trained, tested and compared linear SVM, decision tree, and random forest classification models for strike, movement, and stillness using a window size of 0.4 seconds. Separate linear SVM, decision tree and random forest models were trained, tested, and compared with a window size of three seconds for swallowing behaviors. Following validation of these models, we translated this method to the field with a population of C. horridus in the lower Piedmont of middle Georgia to evaluate the efficacy of externally attached ACTs for remote and continuous monitoring of predatory behaviors by wild-ranging vipers., Acknowledgements Georgia College & State University Recommended Citation Authors Morgan L. Thompson, Georgia College & State University Follow Richard H. Adams, Georgia College & State University Follow Anna F. Tipton, [...]

The evolutionary dynamics of simple sequence repeats (SSRs or microsatellites) across the vertebrate tree of life remain largely undocumented and poorly understood. In this study, we analyzed patterns of genomic microsatellite abundance and evolution across 71 vertebrate genomes. The highest abundances of microsatellites exist in the genomes of ray-finned fishes, squamate reptiles, and mammals, while crocodilian, turtle, and avian genomes exhibit reduced microsatellite landscapes. We used comparative methods to infer evolutionary rates of change in microsatellite abundance across vertebrates and to highlight particular lineages that have experienced unusually high or low rates of change in genomic microsatellite abundance. Overall, most variation in microsatellite content, abundance, and evolutionary rate is observed among major lineages of reptiles, yet we found that several deeply divergent clades (i.e., squamate reptiles and mammals) contained relatively similar genomic microsatellite compositions. Archosauromorph reptiles (turtles, crocodilians, and birds) exhibit reduced genomic microsatellite content and the slowest rates of microsatellite evolution, in contrast to squamate reptile genomes that have among the highest rates of microsatellite evolution. Substantial branch-specific shifts in SSR content in primates, monotremes, rodents, snakes, and fish are also evident. Collectively, our results support multiple major shifts in microsatellite genomic landscapes among vertebrates. Key words: comparative genomics, microsatellite seeding, repeat elements, tandem repeats, simple sequence repeats. La dynamique evolutive des sequences simples repetees (SSR ou microsatellites) au sein des vertebres demeure largement non-documentee et mal connue. Dans ce travail, les auteurs ont analyse l'abondance et revolution des microsatellites chez 71 genomes de vertebres. Les abondances de microsatellites les plus grandes ont ete rencontrees au sein des genomes des poissons dotes de nageoires a rayons, des reptiles a ecailles et des mammiferes, tandis que les genomes des crocodiliens, des tortues et des oiseaux presentaient le moins de microsatellites. Les auteurs ont employe des methodes comparatives pour inferer les taux de changements evolutifs en matiere d'abondance des microsatellites parmi les vertebres et pour mettre en evidence des lignages qui ont connu des taux exceptionnellement eleves ou faibles. Globalement, la majeure partie de la variation en matiere de contenu, d'abondance et de taux d'evolution des microsatellites a ete observee au sein des grands groupes de reptiles, et pourtant, les auteurs ont note que certains clades tres distants (p. ex. les reptiles a ecailles et les mammiferes) presentaient des compositions genomiques semblables en matiere de microsatellites. Les reptiles archosauromorphes (tortues, crocodiliens et oiseaux) affichaient une teneur reduite en microsatellites et les plus faibles taux evolutifs au sein des microsatellites, tandis que les genomes des reptiles a ecailles avaient des taux parmi les plus eleves. Des variations substantielles limitees a certaines branches specifiques ont egalement ete observees chez les primates, les monotremes, les rongeurs, les serpents et les poissons. Ensemble, ces resultats appuient l'hypothese de multiples changements importants dans le paysage des microsatellites chez les vertebres. [Traduit par la Redaction] Mots-cles: genomique comparee, ensemencement de microsatellites, elements repetes, repetitions en tandem, sequences simples repetees., Introduction Microsatellites, also known as simple sequence repeats (SSRs), are 2-6 base pair (bp) nucleotide motifs that are tandemly repeated to form larger DNA stretches usually between 20 and 100 [...]

The ubiquitous cellular heterogeneity underlying many organism-level phenotypes raises questions about what factors drive this heterogeneity and how these complex heterogeneous systems evolve. Here, we use single-cell expression data from a Prairie rattlesnake (Crotalus viridis) venom gland to evaluate hypotheses for signaling networks underlying snake venom regulation and the degree to which different venom gene families have evolutionarily recruited distinct regulatory architectures. Our findings suggest that snake venom regulatory systems have evolutionarily co-opted trans -regulatory factors from extracellular signal-regulated kinase and unfolded protein response pathways that specifically coordinate expression of distinct venom toxins in a phased sequence across a single population of secretory cells. This pattern of co-option results in extensive cell-to-cell variation in venom gene expression, even between tandemly duplicated paralogs, suggesting this regulatory architecture has evolved to circumvent cellular constraints. While the exact nature of such constraints remains an open question, we propose that such regulatory heterogeneity may circumvent steric constraints on chromatin, cellular physiological constraints (e.g. endoplasmic reticulum stress or negative protein–protein interactions), or a combination of these. Regardless of the precise nature of these constraints, this example suggests that, in some cases, dynamic cellular constraints may impose previously unappreciated secondary constraints on the evolution of gene regulatory networks that favors heterogeneous expression. [ABSTRACT FROM AUTHOR]

Few studies have examined the impact of international migration and remittances on poverty in the developing world. This paper fills this lacuna by constructing and analyzing a new data set on international migration, remittances, inequality, and poverty from 71 developing countries. The results show that both international migration and remittances significantly reduce the level, depth, and severity of poverty in the developing world. After instrumenting for the possible endogeneity of international migration, and controlling for various factors, results suggest that, on average, a 10% increase in the share of international migrants in a country's population will lead to a 2.1% decline in the share of people living on less than $1.00 per person per day. After instrumenting for the possible endogeneity of international remittances, a similar 10% increase in per capita official international remittances will lead to a 3.5% decline in the share of people living in poverty. Key words--international migration, remittances, poverty

This paper uses a new data set of 126 intervals from 60 developing countries to analyze the growth elasticity of poverty, that is, how much does poverty decline in percentage terms with a given percentage rise in economic growth. The data set is both broader in coverage and more selective in terms of quality controls than those used in the past. The study finds that while economic growth does reduce poverty in developing countries, the rate of poverty reduction depends very much on how economic growth is defined. Controlling for changes in income inequality, when economic growth is measured by changes in survey mean income (consumption), the growth elasticity of poverty (excluding Eastern Europe and Central Asia) is -2.79; that is, a 10% increase in the survey mean will reduce poverty ($1.00/person/day) by 27.9%. But, when growth is measured by changes in GDP per capita, the growth elasticity of poverty is a statistically insignificant -2.27, which is lower than has previously been estimated. Key words--poverty, inequality, economic growth, growth elasticity of poverty

This paper uses crosscountry data and country-case studies to analyze trends in poverty, inequality and economic growth in the Middle East and North Africa (MENA) region. Compared to other regions, the MENA region has a low incidence of poverty and income inequality. Two factors account for this situation: international migration/remittances and public sector (government) employment. Since the early 1980s international migration to the Persian Gulf and Europe has helped boost the incomes of the poor in the Middle East. At the same time, many MENA countries have used government employment as a means of keeping people employed and out of poverty. Regression analysis of crosscountry data shows that both of these factors have a statistically significant impact on reducing the level and depth of poverty in the MENA region. Key words--Middle East, poverty, income distribution, migration, remittances, government, employment

Remittance and asset relationships in rural Pakistan exhibit distinct characteristics. External remittances have a significant impact on physical asset accumulation, particularly rainfed and irrigated lands. Internal remittances, however, have little impact on any aspect of asset accumulation. While external remittances tend to be invested, internal remittances are used for investment and consumption.

A study was conducted on rural income inequality using a three-year panel data set from Pakistan. Income decomposition techniques and Cobb-Douglas production functions were used. Results showed that agricultural income was the major contributor of overall income inequality among the five sources of rural income. It was also suggested that Pakistan deemphasize on sugarcane production and instead focus on improving technologies for main food and livestock crops.

This article uses three-year panel data to analyse the impact of non-farm income on income inequality in rural Pakistan. After pinpointing the importance of rural non-farm income for the poor, the article decomposes total rural income among five sources: non-farm. agricultural, livestock, rental and transfer. This decomposition shows that non-farm income represents an inequality-decreasing source of income. The study then decomposes the sources of non-farm income. This analysis reveals that while non-farm unskilled labour income has an equalising effect on income distribution, non-farm government income has a disequalising effect., In the past many researchers and policy-makers have viewed the rural economy of the Third World as being synonymous with agriculture. According to this view, rural households receive the bulk [...]

This study uses data collected in rural Egypt to estimate a micro-level model of the economic and demographic determinants of international migration. This model uses predicted income functions to establish origin incomes (incomes excluding remittances). Three findings are noteworthy. First, the results suggest that education may not necessarily be positively correlated with migration. Second, the data indicate that the relationship between income and migration is that of a flat, inverted U-shaped curve. Third, when the combined effects of income and land are considered, males from poor and landless households have the highest propensity to migrate. Poverty and landlessness combine to push rural Egyptians to work abroad., INTRODUCTION A high proportion of internal and international migration in the Third World is caused by individuals seeking better economic opportunities. Internal migrants, usually coming from rural areas, stream into [...]

Sources of income inequality in rural Pakistan is studied using a three-year panel data of 727 households. In agricultural income, the extent to which unequal landownership plays a part in income inequality is also studied. Results indicate that agricultural income contributes the most to equalizing income, while livestock income contributes the least. It also shows that with unaggregated data, returns to labor and crop profit is a greater source of income inequality than unequal landownership.