Chromatin Organization in Sperm May Be the Major Functional Consequence of Base Composition Variation in the Human Genome

Chromatin in sperm is different from that in other cells, with most of the genome packaged by protamines not nucleosomes. Nucleosomes are, however, retained at some genomic sites, where they have the potential to transmit paternal epigenetic information. It is not understood how this retention is specified. Here we show that base composition is the major determinant of nucleosome retention in human sperm, predicting retention very well in both genic and non-genic regions of the genome. The retention of nucleosomes at GC-rich sequences with high intrinsic nucleosome affinity accounts for the previously reported retention at transcription start sites and at genes that regulate development. It also means that nucleosomes are retained at the start sites of most housekeeping genes. We also report a striking link between the retention of nucleosomes in sperm and the establishment of DNA methylation-free regions in the early embryo. Taken together, this suggests that paternal nucleosome transmission may facilitate robust gene regulation in the early embryo. We propose that chromatin organization in the male germline, rather than in somatic cells, is the major functional consequence of fine-scale base composition variation in the human genome. The selective pressure driving base composition evolution in mammals could, therefore, be the need to transmit paternal epigenetic information to the zygote

Evolution of sex-specific pace-of-life syndromes: genetic architecture and physiological mechanisms

Sex differences in life history, physiology, and behavior are nearly ubiquitous across taxa, owing to sex-specific selection that arises from different reproductive strategies of the sexes. The pace-of-life syndrome (POLS) hypothesis predicts that most variation in such traits among individuals, populations, and species falls along a slow-fast pace-of-life continuum. As a result of their different reproductive roles and environment, the sexes also commonly differ in pace-of-life, with important consequences for the evolution of POLS. Here, we outline mechanisms for how males and females can evolve differences in POLS traits and in how such traits can covary differently despite constraints resulting from a shared genome. We review the current knowledge of the genetic basis of POLS traits and suggest candidate genes and pathways for future studies. Pleiotropic effects may govern many of the genetic correlations, but little is still known about the mechanisms involved in trade-offs between current and future reproduction and their integration with behavioral variation. We highlight the importance of metabolic and hormonal pathways in mediating sex differences in POLS traits; however, there is still a shortage of studies that test for sex specificity in molecular effects and their evolutionary causes. Considering whether and how sexual dimorphism evolves in POLS traits provides a more holistic framework to understand how behavioral variation is integrated with life histories and physiology, and we call for studies that focus on examining the sex-specific genetic architecture of this integration

Advancing selection in an SME: Is best practice methodology applicable?

Effective selection tools are important for identifying high caliber employees in SMEs, yet few SMEs use tools created using ‘best practice’ methodology. Selection literature tends to focus on large organizations and is conceptual rather than empirical; which may make it difficult for SMEs to use a best practice approach. This article addresses this by providing an empirical account of the design and validation of two selection tools in a medium-sized recruitment consultancy using a best practice selection methodology. Two work sample tests were developed using critical incident technique interviews, and validated using a concurrent design with existing recruitment consultants who were ‘high’ or ‘low’ performers according to sales output. Results indicated that the tools significantly differentiated between high and low performers, and there was a significant correlation between test performance and individual sales output. Findings are discussed in relation to implications for research and practice in SMEs and selection

The Diana project: pioneering women studying pioneering women

The 2007 winner of the International Award for Entrepreneurship and Small Business Research is the Diana Project team (Candida Brush, Nancy Carter, Elizabeth Gatewood, Patricia Greene and Myra Hart). The Diana Project builds on the vast experience of the team in the field of entrepreneurship in general and women entrepreneurship, business growth and venture capital in particular. The Diana Project has investigated the supply and demand side of growth capital for women entrepreneurs. The research contributes to entrepreneurship theory as well as to practice, filling a void in knowledge on growth-oriented women entrepreneurship. In this article we present and discuss the research contribution of the Diana Project, in the areas of entrepreneurship, women entrepreneurship and venture capital. We specifically discuss the value of researching a specific group of women entrepreneurs, those who want to grow their businesses, that very clearly demonstrates the positive potential of female entrepreneurship. The Diana Project has also moved research on women's entrepreneurship forward since its framework does not treat women entrepreneurs as 'other,' i.e., the project does not presuppose that women's entrepreneurship is similar to or different from men's entrepreneurship. It assumes that women's entrepreneurship is entrepreneurship and studies it from that point of view