Social and cognitive characteristics of adults with intellectual disabilities (ID) place them at risk for inappropriate inclusion in or exclusion from research participation. As we grapple with how to include adults with ID in research in order to secure their right to contribute to scientific advancements and be positioned to derive benefit from ensuing knowledge, it is critical to consider scientific gatekeepers' perspectives on risks of and protections for including adults with ID in research. We surveyed 199 Institutional Review Board members and intellectual disability researchers in the United States to identify their perceptions of specific risks and necessary protections in (hypothetical) research studies. The research studies varied as to whether they included adults with ID in the research sample and the level of harm to which research participants were exposed. Results suggest that identification of psychological, social, and legal risks and necessary protections varied by the disability status of the sample, the level of risk, and the role of the person reviewing the study. For example, participants identified more psychological, information control, legal, and social risks in higher harm research studies. Participants reported a need for more protections in high-harm studies as well as studies that included adults with ID. In some instances the nature of identified risks and protections and respondents' characterization of these risks and necessary protections suggested concerns related specifically to adults with ID. Implications for practice, policy, and future research related to access to research participation are discussed.

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Extensive sequencing of modern and ancient human genomes has revealed that contemporary populations can be explained as the result of recent mixing of a few distinct ancestral genetic lineages1. But the small number of aDNA samples that predate the Last Glacial Maximum means that the origins of these lineages are not well understood. Here, we circumvent the limited sampling by modelling explicitly the effect of climatic changes and terrain on population demography and migrations through time and space, and show that these factors are sufficient to explain the divergence among ancestral lineages. Our reconstructions show that the sharp separation between African and Eurasian lineages is a consequence of only a few limited periods of connectivity through the arid Arabian peninsula, which acted as the gate out of the Arican continent. The subsequent spread across Eurasia was then mostly shaped by mountain ranges, and to a lesser extent deserts, leading to the split of European and Asians, and the further diversification of these two groups. A high tolerance to cold climates allowed the persistence at high latitudes even during the Last Glacial Maximum, maintaining a pocket in Beringia that led to the later, rapid colonisation of the Americas. The advent of food production was associated with an increase in movement2, but mountains and climate have been shown to still play a major role even in this latter period3,4, affecting the mixing of the ancestral lineages that we have shown to be shaped by those two factors in the first place.

Species range contractions both contribute to, and result from, biological annihilation, yet do not receive the same attention as extinctions. Range contractions can lead to marked impacts on populations but are usually characterized only by reduction in extent of range. For effective conservation, it is critical to recognize that not all range contractions are the same. We propose three distinct patterns of range contraction: shrinkage, amputation, and fragmentation. We tested the impact of these patterns on populations of a generalist species using forward-time simulations. All three patterns caused 86–88% reduction in population abundance and significantly increased average relatedness, with differing patterns in declines of nucleotide diversity relative to the contraction pattern. The fragmentation pattern resulted in the strongest effects on post-contraction genetic diversity and structure. Defining and quantifying range contraction patterns and their consequences for Earth’s biodiversity would provide useful and necessary information to combat biological annihilation.

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