Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)

Acoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication

Phonetische und korpus-linguistische Methoden bei der Analyse vokaler Kommunikation von freilebenden Schimpansen im Tai National Forest

Über die letzten Jahrzehnte haben sich unsere Kenntnisse über die vokalen Kommunikationssysteme bei Menschenaffen enorm erweitert und aber auch das Verständnis zur Evolution des Kommunikationssystems unserer eigenen Spezies stark gewandelt. Allein nur die Studien zur Kommunikation unter Schim- pansen haben gezeigt, dass es eine Reihe von gruppenspezifische und kontexts- pezifischen Lautäußerungen gibt. Es ist klar geworden, dass die Komplexität der Strukturen und ihrer kommunikativen wie sozialen Funktionen lange unterschätzt wurde und selbst auch die akustischen und artikulatorischen Vorgänge noch nicht vollständig verstanden sind. Die dramatische Abnahme der verbliebenen Popula- tionen ist allerdings wenig hilfreich und wirkt sich ebenso auf die Bedingungen für deren Erforschung und die Anforderung (z.B. an Software) an sie aus. Für diesen Beitrag werden anhand einer aktuellen Studie zu akustischen und artikulatorischen Charakteristika von Vokalisierungen bei freilebenden Schimpansen im Taï National Forest (Elfenbeinküste) grundlegende Probleme analysiert wie sie sich aus Sicht der Erforschung des Sprechens beim Menschen ergeben. Das vorgestellte Projekt fokussiert die individuelle und gruppenspezifische Ausprägung kontextsensitiver Laute unter besonderer Berücksichtigung der beobachtbaren oralen Artikulation. Hierbei möchten wir gerade die Desiderata im methodisch-technischen Bereich (Datenerhebung, Transkription und Annotation, akustische und artikulatorische Pa- rametrisierung von Audio und Video, Datenverwaltung) aufzeigen und versuchen Lösungsvorschläge zu unterbreiten, aber auch Hilfe in der Community suche

Higher fundamental frequency in bonobos is explained by larynx morphology

Acoustic signals, shaped by natural and sexual selection, reveal ecological and social selection pressures [1]. Examining acoustic signals together with morphology can be particularly revealing. But this approach has rarely been applied to primates, where clues to the evolutionary trajectory of human communication may be found. Across vertebrate species, there is a close relationship between body size and acoustic parameters, such as formant dispersion and fundamental frequency (f0). Deviations from this acoustic allometry usually produce calls with a lower f0 than expected for a given body size, often due to morphological adaptations in the larynx or vocal tract [2]. An unusual example of an obvious mismatch between fundamental frequency and body size is found in the two closest living relatives of humans, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Although these two ape species overlap in body size [3], bonobo calls have a strikingly higher f0 than corresponding calls from chimpanzees [4]. Here, we compare acoustic structures of calls from bonobos and chimpanzees in relation to their larynx morphology. We found that shorter vocal fold length in bonobos compared to chimpanzees accounted for species differences in f0, showing a rare case of positive selection for signal diminution in both bonobo sexes

Chimpanzee vowel-like sounds and voice quality suggest formant space expansion through the hominoid lineage

The origins of human speech are obscure; it is still unclear what aspects are unique to our species or shared with our evolutionary cousins, in part due to a lack of common framework for comparison. We asked what chimpanzee and human vocal production acoustics have in common. We examined visible supra-laryngeal articulators of four major chimpanzee vocalizations (hoos, grunts, barks, screams) and their associated acoustic structures, using techniques from human phonetic and animal communication analysis. Data were collected from wild adult chimpanzees, Taï National Park, Ivory Coast. Both discriminant and principal component classification procedures revealed classification of call types. Discriminating acoustic features include voice quality and formant structure, mirroring phonetic features in human speech. Chimpanzee lip and jaw articulation variables also offered similar discrimination of call types. Formant maps distinguished call types with different vowel-like sounds. Comparing our results with published primate data, humans show less F1–F2 correlation and further expansion of the vowel space, particularly for [i] sounds. Unlike recent studies suggesting monkeys achieve human vowel space, we conclude from our results that supra-laryngeal articulatory capacities show moderate evolutionary change, with vowel space expansion continuing through hominoid evolution. Studies on more primate species will be required to substantiate this.This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’

Radiation-hypersensitive cancer patients do not manifest protein expression abnormalities in components of the nonhomologous end-joining (NHEJ) pathway

Radiation therapy (RT) is utilised for the treatment of around half of all oncology patients during the course of their illness. Despite great clinical progress in the rational deployment of RT, the underlying molecular basis for its efficacy and toxicity are currently imperfectly understood. In this study, we took a biochemical approach to evaluate the potential role of key ionising radiation repair proteins in the treatment outcomes of patients with severe acute or late RT side effects. Lymphoblastoid cell lines were established from blood samples from 36 radiosensitive cases and a number of controls (the latter had had RT but did not develop significant toxicity). The expression level and migration of key proteins from the nonhomologous end-joining (NHEJ) pathway was evaluated by Western blot analysis on cases and controls. We did not observe any abnormalities in expression level or migration pattern of the following NHEJ proteins in radiosensitive cancer cases: Ku70, Ku80, XRCC4, DNA Ligase IV. These important negative results provide evidence that mutations that affect protein expression of these NHEJ components are unlikely to underlie clinical radiation sensitivity

Genetic Evidence That the Non-Homologous End-Joining Repair Pathway Is Involved in LINE Retrotransposition

Long interspersed elements (LINEs) are transposable elements that proliferate within eukaryotic genomes, having a large impact on eukaryotic genome evolution. LINEs mobilize via a process called retrotransposition. Although the role of the LINE-encoded protein(s) in retrotransposition has been extensively investigated, the participation of host-encoded factors in retrotransposition remains unclear. To address this issue, we examined retrotransposition frequencies of two structurally different LINEs—zebrafish ZfL2-2 and human L1—in knockout chicken DT40 cell lines deficient in genes involved in the non-homologous end-joining (NHEJ) repair of DNA and in human HeLa cells treated with a drug that inhibits NHEJ. Deficiencies of NHEJ proteins decreased retrotransposition frequencies of both LINEs in these cells, suggesting that NHEJ is involved in LINE retrotransposition. More precise characterization of ZfL2-2 insertions in DT40 cells permitted us to consider the possibility of dual roles for NHEJ in LINE retrotransposition, namely to ensure efficient integration of LINEs and to restrict their full-length formation

Cellular Radiosensitivity: How much better do we understand it?

Purpose: Ionizing radiation exposure gives rise to a variety of lesions in DNA that result in genetic instability and potentially tumorigenesis or cell death. Radiation extends its effects on DNA by direct interaction or by radiolysis of H2O that generates free radicals or aqueous electrons capable of interacting with and causing indirect damage to DNA. While the various lesions arising in DNA after radiation exposure can contribute to the mutagenising effects of this agent, the potentially most damaging lesion is the DNA double strand break (DSB) that contributes to genome instability and/or cell death. Thus in many cases failure to recognise and/or repair this lesion determines the radiosensitivity status of the cell. DNA repair mechanisms including homologous recombination (HR) and non-homologous end-joining (NHEJ) have evolved to protect cells against DNA DSB. Mutations in proteins that constitute these repair pathways are characterised by radiosensitivity and genome instability. Defects in a number of these proteins also give rise to genetic disorders that feature not only genetic instability but also immunodeficiency, cancer predisposition, neurodegeneration and other pathologies. Conclusions: In the past fifty years our understanding of the cellular response to radiation damage has advanced enormously with insight being gained from a wide range of approaches extending from more basic early studies to the sophisticated approaches used today. In this review we discuss our current understanding of the impact of radiation on the cell and the organism gained from the array of past and present studies and attempt to provide an explanation for what it is that determines the response to radiation

CsA can induce DNA double-strand breaks: implications for BMT regimens particularly for individuals with defective DNA repair

Several human disorders mutated in core components of the major DNA double-strand break (DSB) repair pathway, non-homologous end joining (NHEJ), have been described. Cell lines from these patients are characterized by sensitivity to DSB-inducing agents. DNA ligase IV syndrome (LIG4) patients specifically, for unknown reasons, respond particularly badly following treatment for malignancy or BMT. We report the first systematic evaluation of the response of LIG4 syndrome to compounds routinely employed for BMT conditioning. We found human pre-B lymphocytes, a key target population for BMT conditioning, when deficient for DNA ligase IV, unexpectedly exhibit significant sensitivity to CsA the principal prophylaxis for GVHD. Furthermore, we found that CsA treatment alone or in combination with BU and fludarabine resulted in increased levels of DSBs specifically in LIG4 syndrome cells compared to wild-type or Artemis-deficient cells. Our study shows that CsA can induce DSBs and that LIG4 syndrome patient's fail to adequately repair this damage. These DSBs likely arise as a consequence of DNA replication in the presence of CsA. This work has implications for BMT and GVHD management in general and specifically for LIG4 syndrome

Single Molecule PCR Reveals Similar Patterns of Non-Homologous DSB Repair in Tobacco and Arabidopsis

DNA double strand breaks (DSBs) occur constantly in eukaryotes. These potentially lethal DNA lesions are repaired efficiently by two major DSB repair pathways: homologous recombination and non-homologous end joining (NHEJ). We investigated NHEJ in Arabidopsis thaliana and tobacco (Nicotiana tabacum) by introducing DNA double-strand breaks through inducible expression of I-SceI, followed by amplification of individual repair junction sequences by single-molecule PCR. Using this process over 300 NHEJ repair junctions were analysed in each species. In contrast to previously published variation in DSB repair between Arabidopsis and tobacco, the two species displayed similar DSB repair profiles in our experiments. The majority of repair events resulted in no loss of sequence and small (1–20 bp) deletions occurred at a minority (25–45%) of repair junctions. Approximately ∼1.5% of the observed repair events contained larger deletions (>20 bp) and a similar percentage contained insertions. Strikingly, insertion events in tobacco were associated with large genomic deletions at the site of the DSB that resulted in increased micro-homology at the sequence junctions suggesting the involvement of a non-classical NHEJ repair pathway. The generation of DSBs through inducible expression of I-SceI, in combination with single molecule PCR, provides an effective and efficient method for analysis of individual repair junctions and will prove a useful tool in the analysis of NHEJ