Rapid adaptive evolution of colour vision in the threespine stickleback radiation.

Vision is a sensory modality of fundamental importance for many animals, aiding in foraging, detection of predators and mate choice. Adaptation to local ambient light conditions is thought to be commonplace, and a match between spectral sensitivity and light spectrum is predicted. We use opsin gene expression to test for local adaptation and matching of spectral sensitivity in multiple independent lake populations of threespine stickleback populations derived since the last ice age from an ancestral marine form. We show that sensitivity across the visual spectrum is shifted repeatedly towards longer wavelengths in freshwater compared with the ancestral marine form. Laboratory rearing suggests that this shift is largely genetically based. Using a new metric, we found that the magnitude of shift in spectral sensitivity in each population corresponds strongly to the transition in the availability of different wavelengths of light between the marine and lake environments. We also found evidence of local adaptation by sympatric benthic and limnetic ecotypes to different light environments within lakes. Our findings indicate rapid parallel evolution of the visual system to altered light conditions. The changes have not, however, yielded a close matching of spectrum-wide sensitivity to wavelength availability, for reasons we discuss

Genes, Education, and Labor Market Outcomes: Evidence from the Health and Retirement Study

Recent advances have led to the discovery of specific genetic variants that predict educational attainment. We study how these variants, summarized as a genetic score variable, are associated with human capital accumulation and labor market outcomes in the Health and Retirement Study (HRS). We demonstrate that the same genetic score that predicts education is also associated with higher wages, but only among individuals with a college education. Moreover, the genetic gradient in wages has grown in more recent birth cohorts, consistent with interactions between technological change and labor market ability. We also show that individuals who grew up in economically disadvantaged households are less likely to go to college when compared to individuals with the same genetic score, but from higher socioeconomic status households. Our findings provide support for the idea that childhood socioeconomic status is an important moderator of the economic returns to genetic endowments. Moreover, the finding that childhood poverty limits the educational attainment of high-ability individuals suggests the existence of unrealized human potential

Can village savings and loan groups be a potential tool in the malnutrition fight? Mixed method findings from Mozambique

Child malnutrition is a pervasive problem in sub-Saharan Africa that affects individual and national development. This article examines the impact of participation in village savings and loan (VSL) groups, alone and in combination with a rotating labor scheme called Ajuda Mútua (AM), on household and child nutritional outcomes in Nampula Province in Mozambique. It combines findings from an impact evaluation and a qualitative exploration of the dynamics underlying nutritional outcomes.Three pairs of districts were randomly allocated to two interventions (VSL or VSL. +. AM) or control. The impact evaluation utilized a prospective, longitudinal design. In total, 1276 households were surveyed at baseline in 2009 and three years later. Difference-in-difference propensity score matching models estimated program impacts on months of food sufficiency and household dietary diversity scores (HDDS) at the household level, and on individual dietary diversity scores (IDDS) and weight-for-age at the child level. In the qualitative study, in-depth interviews (IDIs) were completed with a subset of 36 VSL and 36 VSL. +. AM participants from two districts who had taken part in the two surveys. Transcripts were analyzed using thematic analysis.Survey data indicate that both interventions had a statistically significant, positive effect on months of food sufficiency. The HDDS increased for VSL. +. AM households and their matched controls; however, the increase was smaller for the VSL. +. AM group. The difference in increase between the two groups was statistically significant. At the child level, participation in VSL only was found to increase the IDDS. There was no significant effect for weight-for-age. Mean values for both the HDDS and the IDDS remained low. IDIs confirmed that there were improvements in seasonal and transitory food insecurity, which occur when recurring periods of extreme scarcity or sporadic crises are experienced. Due to the timing of the cycle, VSLs provided participants with an infusion of cash to purchase food during the hunger season. VSLs and AMs also offered mechanisms to cope with unexpected events through loans and social support. However, IDIs highlighted lack of money as a persistent challenge in accessing foods to supplement home-grown staples for a diversified nutritional intake. Though parents tended to be aware of the nutritional needs of children, they faced financial constraints in meeting them. There were also indications of a sex gap between control over resources by men and the role played by women in child nutrition.Findings underscore the potential of economic-strengthening activities such as VSLs for improving seasonal and transitory food security, but highlight the need for additional supporting interventions in order to overcome chronic nutritional challenges

A novel G-quadruplex-forming GGA repeat region in the c-myb promoter is a critical regulator of promoter activity

The c-myb promoter contains multiple GGA repeats beginning 17 bp downstream of the transcription initiation site. GGA repeats have been previously shown to form unusual DNA structures in solution. Results from chemical footprinting, circular dichroism and RNA and DNA polymerase arrest assays on oligonucleotides representing the GGA repeat region of the c-myb promoter demonstrate that the element is able to form tetrad:heptad:heptad:tetrad (T:H:H:T) G-quadruplex structures by stacking two tetrad:heptad G-quadruplexes formed by two of the three (GGA)4 repeats. Deletion of one or two (GGA)4 motifs destabilizes this secondary structure and increases c-myb promoter activity, indicating that the G-quadruplexes formed in the c-myb GGA repeat region may act as a negative regulator of the c-myb promoter. Complete deletion of the c-myb GGA repeat region abolishes c-myb promoter activity, indicating dual roles of the c-myb GGA repeat element as both a transcriptional repressor and an activator. Furthermore, we demonstrated that Myc-associated zinc finger protein (MAZ) represses c-myb promoter activity and binds to the c-myb T:H:H:T G-quadruplexes. Our findings show that the T:H:H:T G-quadruplex-forming region in the c-myb promoter is a critical cis-acting element and may repress c-myb promoter activity through MAZ interaction with G-quadruplexes in the c-myb promoter

Data from: Rapid adaptive evolution of colour vision in the threespine stickleback radiation

Vision is a sensory modality of fundamental importance for many animals, aiding in foraging, detection of predators, and mate choice. Adaptation to local ambient light conditions is thought to be commonplace, and a match between spectral sensitivity and light spectrum is predicted. We use opsin gene expression to test for local adaptation and matching of spectral sensitivity in multiple independent lake populations of threespine stickleback populations derived since the last ice age from an ancestral marine form. We show that sensitivity across the visual spectrum is shifted repeatedly towards longer wavelengths in freshwater compared with the ancestral marine form. Laboratory rearing suggests this shift is largely genetically based. Using a new metric, we found that the magnitude of shift in spectral sensitivity in each population corresponds strongly to the transition in the availability of different wavelengths of light between the marine and lake environment. We also found evidence of local adaptation by sympatric benthic and limnetic ecotypes to different light environments within lakes. Our findings indicate rapid parallel evolution of the visual system to altered light conditions. The changes have not, however, yielded a close matching of spectrum-wide sensitivity to wavelength availability, for reasons we discuss

DISSERTATION PROPOSAL: PATTERNS OF EMERGENT LEADERSHIP IN AD HOC VIRTUAL TEAMS Committee:

Ad hoc virtual teams are the most ubiquitous type of virtual team found in organizations today. These are fast-forming teams that are assembled to perform short-term tasks, after which they are dissolved. These teams are more-often-than-not composed of peers, in that members are drawn from similar levels of organizations. They also tend to be self-managing, in that there is no formal or appointed leader. Recent research in the virtual teams literature indicates leadership in these types of teams can take more than one form. Although research on co-located teams has tended to focus on the emergence of a single individual as a team leader, evidence from the virtual teams literature and new theories of team leadership have raised the possibility that the leadership structure that emerges from team interaction can take more than one form. Leadership may be centralized in a single individual or it may be distributed (i.e., shared) among team members, with different team members taking on leadership roles as the team performs its task. As such, this study is guided by a single research question: What patterns o

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