Mutation and selection explain why many eukaryotic centromeric DNA sequences are often A + T rich.

We have used chromosome engineering to replace native centromeric DNA with different test sequences at native centromeres in two different strains of the fission yeast Schizosaccharomyces pombe and have discovered that A + T rich DNA, whether synthetic or of bacterial origin, will function as a centromere in this species. Using genome size as a surrogate for the inverse of effective population size (Ne) we also show that the relative A + T content of centromeric DNA scales with Ne across 43 animal, fungal and yeast (Opisthokonta) species. This suggests that in most of these species the A + T content of the centromeric DNA is determined by a balance between selection and mutation. Combining the experimental results and the evolutionary analyses allows us to conclude that A + T rich DNA of almost any sequence will function as a centromere in most Opisthokonta species. The fact that many G/C to A/T substitutions are unlikely to be selected against may contribute to the rapid evolution of centromeric DNA. We also show that a neo-centromere sequence is not simply a weak version of native centromeric DNA and suggest that neo-centromeres require factors either for their propagation or establishment in addition to those required by native centromeres.

The Citizen Psychologist Curriculum-Preparing psychologists for public service: The 2018 American Psychological Association Presidential Initiative.

This article describes a curriculum developed as part of the American Psychological Association President Jessica Henderson Daniel's, 2018 Presidential Initiative-The Citizen Psychologist. The curriculum is designed to prepare the next generation of Citizen Psychologists to provide the broadest sense of service as leaders in their communities and in public service psychology. The curriculum prepares the learner to bring psychological knowledge, science, and expertise to bear on existing challenges to improve community well-being locally, nationally, and globally. This includes addressing the services needs of various vulnerable populations such as veterans, prisoners, the seriously mentally ill, those with substance abuse problems, children, and older adults. Competency-based curricula are presented in a series of modules, each dedicated to a level of education and training from high school through lifelong learning. Each module presents learning outcomes, activities, and resources designed to develop level-specific competencies. Steps for implementation and recommendations at the local and national level are provided. Implications of incorporating the Citizen Psychologist curriculum in education and training programs are discussed including encouraging students to explore volunteer and career opportunities in public service psychology. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Development and validation of the Internalized Racial Oppression Scale for Black individuals.

This article describes the development and validation of the Internalized Racial Oppression Scale (IROS) for Black individuals in 2 studies using a total sample of 468 Black college students. The IROS is intended to measure the degree to which racial oppression is internalized and replicated by Black individuals in the United States. An exploratory factor analysis suggested a five-factor solution: Belief in the Biased Representation of History (BRH), Devaluation of the African Worldview and Motifs (DAW), Alteration of Physical Appearance (APA), Internalization of Negative Stereotypes (INS), and Hair Change (HC). Confirmatory factory analysis supported an adequate model fit of a four-factor model: BRH, APA, INS, and HC. All factors of the IROS were positively correlated with the Pre-Encounter subscale of the Racial Identity Attitude Scale (RIAS-B; J. E. Helms & T. A. Parham, 1996), and 4 of the factors were negatively correlated with the Immersion/Emersion subscale of the RIAS-B. Four factors of the IROS were negatively correlated with all subscales and total scores of the African Self-Consciousness Scale (J. A. Baldwin & Y. R. Bell, 1985). These results provide some support of the validity of the IROS.