Single-cell transcriptomics on mouse nociceptors has transformed our understanding of pain mechanisms. Equivalent information from human nociceptors is lacking. We used spatial transcriptomics to molecularly characterize transcriptomes of single dorsal root ganglion (DRG) neurons from 8 organ donors. We identified 10 clusters of human sensory neurons, 6 of which are C nociceptors, 1 Aβ nociceptor, 1 Aδ, and 2 Aβ subtypes. These neuron subtypes have distinct expression profiles from rodents and non-human primates and we identify new markers for each of these subtypes that can be applied broadly in human studies. We also identify sex differences, including a marked increase in CALCA expression in female putative itch nociceptors. Our data open the door to new pain targets and unparalleled molecular characterization of clinical sensory disorders.
Through the processes of natural selection and genetic drift, allopatric populations diverge genetically and may ultimately become reproductively incompatible. In cases of prezygotic reproductive isolation, candidate systems for speciation genes logically include genes involved in mate or gamete recognition. However, where only postzygotic isolation exists, candidate speciation genes could include any genes that affect hybrid performance. We hypothesize that because mitochondrial genes frequently evolve more rapidly than the nuclear genes with which they interact, interpopulation hybridization might be particularly disruptive to mitochondrial function. Understanding the potential impact of intergenomic (nuclear and mitochondrial) coadaptation on the evolution of allopatric populations of the intertidal copepod Tigriopus californicus has required a broadly integrative research program; here we present the results of experiments spanning the spectrum of biological organization in order to demonstrate the consequences of molecular evolution on physiological performance and organismal fitness. We suggest that disruption of mitochondrial function, known to result in a diverse set of human diseases, may frequently underlie reduced fitness in interpopulation and interspecies hybrids in animals.
Since Stack’s (1974) landmark ethnography of kin support in a close-knit group of poor black mothers in the Midwest, there has been ample research on social support among low-income black families. While this body of work has largely painted a picture of the cohesive and supportive nature of families in black communities, recent research has highlighted the limited nature of kin support, especially the support available to low-income black mothers. Much of this work, however, has focused primarily on urban black mothers and paid less attention to the conditions that poor rural black mothers face when seeking and giving family support. Using longitudinal ethnographic data from a sample of 16 low-income black mothers in the rural South, we draw on social exchange, negotiated-order, and social capital perspectives to scrutinize the nature and costs of kin support in family networks marked by limited resources, instability, and chronic need. Our findings reveal the centrality of problematic resources and unpredictable family networks as conditions that diminish mothers’ autonomy and compromise important "side bets" as mothers seek out, manage, and repay support. Implications of this study for theories of social support and social capital are also discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.