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Abstract Classical genetic studies have identified many cases of pleiotropy where mutations in individual genes alter many different phenotypes. Quantitative genetic studies of natural genetic variants frequently examine one or a few traits, limiting their potential to identify pleiotropic effects of natural genetic variants. Widely adopted community association panels have been employed by plant genetics communities to study the genetic basis of naturally occurring phenotypic variation in a wide range of traits. High-density genetic marker data—18M markers—from 2 partially overlapping maize association panels comprising 1,014 unique genotypes grown in field trials across at least 7 US states and scored for 162 distinct trait data sets enabled the identification of of 2,154 suggestive marker-trait associations and 697 confident associations in the maize genome using a resampling-based genome-wide association strategy. The precision of individual marker-trait associations was estimated to be 3 genes based on a reference set of genes with known phenotypes. Examples were observed of both genetic loci associated with variation in diverse traits (e.g., above-ground and below-ground traits), as well as individual loci associated with the same or similar traits across diverse environments. Many significant signals are located near genes whose functions were previously entirely unknown or estimated purely via functional data on homologs. This study demonstrates the potential of mining community association panel data using new higher-density genetic marker sets combined with resampling-based genome-wide association tests to develop testable hypotheses about gene functions, identify potential pleiotropic effects of natural genetic variants, and study genotype-by-environment interaction.
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Pinter-Wollman, Noa (Ed.)Abstract Fission–fusion dynamics have evolved in a broad range of animal taxa and are thought to allow individuals to mitigate feeding competition. While this is the principal benefit of fission–fusion, few studies have evaluated its costs. We compared gregariousness, foraging budgets, and social budgets between lactating bonobos and chimpanzees from wild populations to evaluate potential costs. Both species exhibit fission–fusion dynamics, but chimpanzees, particularly in East African populations, appear to experience higher feeding competition than bonobos. We expected lactating chimpanzees to be less gregarious than lactating bonobos; reduced gregariousness should allow lactating chimpanzees to mitigate the costs of higher feeding competition without requiring more foraging effort. However, we expected the reduced gregariousness of lactating chimpanzees to limit their time available for affiliative interactions. Using long-term data from LuiKotale bonobos and Gombe chimpanzees, we found that lactating chimpanzees were indeed less gregarious than lactating bonobos, while feeding and travel time did not differ between species. Contrary to our predictions, lactating females did not differ in social interaction time, and lactating chimpanzees spent proportionately more time interacting with individuals other than their immature offspring. Our results indicate that lactating chimpanzees can maintain social budgets comparable to lactating bonobos despite reduced gregariousness and without incurring additional foraging costs. We discuss potential explanations for why lactating bonobos are more gregarious.more » « less
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Abstract Objectives The prolonged juvenile period exhibited by primates is an evolutionary conundrum. Here we examine wild chimpanzee feeding development in the context of two hypotheses regarding prolonged development in primates: the needing‐to‐learn hypothesis and the expensive brain hypothesis.
Material and Methods We studied wild chimpanzee (
Pan troglodytes schweinfurthii ) offspring at Gombe National Park, Tanzania. We analyzed 41 years of observational behavioral data collected between 1975 and 2016 from 81 offspring. We characterized feeding development in the first 10 years of life via four different measures: (1) proportion of observation time spent feeding; (2) diet composition; (3) diet breadth; and (4) diet maturity as measured by similarity to maternal diet. We used mixed effects models to examine changes with age and by sex, while controlling for season.Results Feeding time, diet breadth, and diet maturity exhibited the most substantial increases with age in the first 6 years, with no significant change thereafter. Males and females showed different patterns of change in diet breadth by age, but did not differ by age 10. Diet composition did not change significantly with age and did not differ by sex.
Discussion We found that chimpanzee offspring attained adult‐like feeding behaviors between 4 and 6 years of age, concomitant with the completion of weaning. Thus, our data do not support the needing‐to‐learn feeding skills hypothesis of a prolonged juvenile period, but additional data are needed to evaluate how and when adolescent chimpanzees are able to make foraging decisions independent of their mothers. Existing data on growth provides support for the expensive brain hypothesis, however, these hypotheses are not necessarily mutually exclusive. As more studies across taxa accumulate sufficient datasets on a range of developmental metrics, we will be able to achieve a more robust understanding of prolonged development in primates.
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Abstract Objectives A key feature of human life history evolution is that modern humans wean their infants 2–4 years earlier on average than African apes. However, our understanding of weaning variation in apes remains limited. Here we provide the first such report in chimpanzees by examining weaned age variation using long‐term data from Gombe National Park, Tanzania.
Material and Methods We analyzed 41 years of observational behavioral data from 65 offspring of 29 mothers to examine the relationships between weaned age (defined as cessation of suckling) in wild chimpanzees and maternal age, dominance rank and parity, and offspring sex. We used Cox proportional hazards regression with mixed effects to model time to weaning and to examine potential sources of variation in offspring weaned age.
Results We found that male offspring were less likely than female offspring to wean by a given age and that weaned age of males varied more than weaned age of females. In addition, maternal dominance rank interacted with offspring age, such that low‐ranking mothers were less likely to wean offspring early, but this effect decreased with offspring age.
Discussion We found that male offspring and offspring of low‐ranking females were less likely to wean early, but did not find evidence for variable weaning according to maternal age or parity. As more data accumulate, we will be better able to disentangle the effects of maternal dominance rank, age and parity. Such studies will not only provide a richer understanding of living ape life history characteristics, but will also provide an important framework for understanding the evolution of early weaning in humans.
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Abstract Anticoagulants are commonly utilized during surgeries and to treat thrombotic diseases like stroke and deep vein thrombosis. However, conventional anticoagulants have serious side‐effects, narrow therapeutic windows, and lack safe reversal agents (antidotes). Here, an alternative RNA origami displaying RNA aptamers as target‐specific anticoagulant is described. Improved design and construction techniques for self‐folding, single‐molecule RNA origami as a platform for displaying pre‐selected RNA aptamers with precise orientational and spatial control are reported. Nuclease resistance is added using 2′‐fluoro‐modified pyrimidines during in vitro transcription. When four aptamers are displayed on the RNA origami platform, the measured thrombin inhibition and anticoagulation activity is higher than observed for free aptamers, ssRNA‐linked RNA aptamers, and RNA origami displaying fewer aptamers. Importantly, thrombin inhibition is immediately switched off by addition of specific reversal agents. Results for single‐stranded DNA (ssDNA) and single‐stranded peptide nucleic acid (PNA) antidotes show restoration of 63% and 95% coagulation activity, respectively. To demonstrate potential for practical, long‐term storage for clinical use, RNA origami is freeze‐dried, and stored at room temperature. Freshly produced and freeze‐dried RNA show identical levels of activity in coagulation assays. Compared to current commercial intravenous anticoagulants, RNA origami‐based molecules show promise as safer alternatives with rapid activity switching for future therapeutic applications.
