Demographic Expansions and the Emergence of Host Specialization in Genetically Distinct Ecotypes of the Tick-Transmitted Bacterium Anaplasma phagocytophilum.

In Europe, genetically distinct ecotypes of the tick-vectored bacterium Anaplasma phagocytophilum circulate among mammals in three discrete enzootic cycles. To date, potential ecological factors that contributed to the emergence of these divergent ecotypes have been poorly studied. Here, we show that the ecotype that predominantly infects roe deer (Capreolus capreolus) is evolutionarily derived. Its divergence from a host generalist ancestor occurred after the last glacial maximum as mammal populations, including roe deer, recolonized the European mainland from southern refugia. We also provide evidence that this host specialist ecotype's effective population size (Ne) has tracked changes in the population of its roe deer host. Specifically, both host and bacterium have undergone substantial increases in Ne over the past 1,500 years. In contrast, we show that while it appears to have undergone a major population expansion starting ~3,500 years ago, in the past 500 years, the contemporary host generalist ecotype has experienced a substantial reduction in genetic diversity levels, possibly as a result of reduced opportunities for transmission between competent hosts. IMPORTANCE The findings of this study reveal specific events important for the evolution of host specialization in a naturally occurring, obligately intracellular bacterial pathogen. Specifically, they show that host range shifts and the emergence of host specialization may occur during periods of population growth in a generalist ancestor. Our results also demonstrate the close correlation between demographic patterns in host and pathogen for a specialist system. These findings have important relevance for understanding the evolution of host range diversity. They may inform future work on host range dynamics, and they provide insights for understanding the emergence of pathogens that have human and veterinary health implications.

Self-Conscious Emotions and the Right Fronto-Temporal and Right Temporal Parietal Junction.

For more than two decades, research focusing on both clinical and non-clinical populations has suggested a key role for specific regions in the regulation of self-conscious emotions. It is speculated that both the expression and the interpretation of self-conscious emotions are critical in humans for action planning and response, communication, learning, parenting, and most social encounters. Empathy, Guilt, Jealousy, Shame, and Pride are all categorized as self-conscious emotions, all of which are crucial components to one's sense of self. There has been an abundance of evidence pointing to the right Fronto-Temporal involvement in the integration of cognitive processes underlying the expression of these emotions. Numerous regions within the right hemisphere have been identified including the right temporal parietal junction (rTPJ), the orbitofrontal cortex (OFC), and the inferior parietal lobule (IPL). In this review, we aim to investigate patient cases, in addition to clinical and non-clinical studies. We also aim to highlight these specific brain regions pivotal to the right hemispheric dominance observed in the neural correlates of such self-conscious emotions and provide the potential role that self-conscious emotions play in evolution.