Peering in mature, captive bonobos (Pan paniscus)

“Peering”—close-proximity staring at the mouth of another—was observed in ten (three males and seven females) mature (at least 7 years old) bonobos (Pan paniscus) living in three social groups at the San Diego Zoo and Wild Animal Park. Instantaneous scan samples, taken at 2-min intervals, over a three-and-a-half year period, yielded 617 observations of peering (1.4 per observation hour). Food was exchanged in only 15 of these scans. Peering was most often performed by younger animals and was primarily directed toward older females (“matrons”). In a given dyad, the animal more likely to peer at the other was also more like to both peer and be peered at if they frequently groomed and infrequently displayed aggression at a given female. An adolescent male showed the highest frequency of peering when living with two older females, but dropped to adult male levels when later housed with two younger (albeit mature) females. A reversal in which animal was more likely to peer, follow, and groom occurred in one female dyad, after the birth of the younger animal's first infant. After a similar birth in the other group, no such changes were observed. We discuss how these and related findings, in conjunction with what is known of the social structure of this species, suggest that one possible function of peering in bonobos may be as a signal acknowledging female status.     

Peering is not a formal indicator of subordination in bonobos (Pan paniscus)

It has been suggested that peering behavior in bonobos is a formal signal acknowledging social dominance status. We investigated whether peering meets the published criteria for a formal signal of subordination in five captive groups of bonobos. The degree of linearity in the set of peering relationships was significantly high in all study groups, and a linear rank order was found. However, unidirectionality was low, and there was little correspondence between the peering order and the agonistic dominance rank. Therefore, peering does not satisfy the criteria of a formal subordination indicator. We also studied the relation between peering and agonistic dominance rank, age, and sex. Animals directed peering significantly more often at high-ranking animals in four of the groups. We suggest that peering is indirectly related to dominance rank by the resource-holding potential of individuals. In contexts where dominant individuals can monopolize resources, peerers may direct their attention at those high-ranking animals. When resources are distributed more evenly, high-ranking animals may peer down the hierarchy. We speculate on the reasons why a formal dominance or subordination signal appears to be absent in bonobos.     

Peering deeply inside the branch

The actin-related protein 2/3 (Arp2/3) story has captivated the cytoskeleton community for over a decade. Not only does this complex nucleate new actin filaments, but it also anchors them into a dendritic meshwork that is used in many cellular contexts such as lamellipodial protrusion, endosome rocketing, and the movement of pathogens. One key piece of this puzzle that has been missing is a detailed structure of the Arp2/3-actin branch. Using electron tomography and computational docking, Rouiller et al. (Rouiller, I., X.-P. Xu, K.J. Amann, C. Egile, S. Nickell, D. Nicastro, R. Li, T.D. Pollard, N. Volkmann, and D. Hanein. 2008. J. Cell Biol. 180:887-895) present an elegant and intriguing structure of the Arp2/3 complex-mediated actin branch.     

A cautiously optimistic vision for marker-assisted breeding

Even though marker-assisted selection now plays a prominent role in the field of plant breeding, examples of successful, practical outcomes are rare. It is clear that DNA markers hold great promise, but realizing that promise remains elusive. Despite innovations like better marker systems and improved genetic mapping strategies, most marker associations are not sufficiently robust for successful marker-assisted selection. In large part this is due to inadequate experimental design. Molecular breeders must reassess their research programs so that DNA marker work leads to useful selection tools and valuable germplasm. As molecular breeders adopt more rigorous experimental guidelines and ambitious goals, they also need to integrate the growing body of knowledge from genomics and bioinformatics.     

Peering inside lipid rafts and caveolae

Clustering of proteins into membrane microdomains, such as lipid rafts and caveolae, could act as a mechanism for regulating cell signaling and other cellular functions. Certain lipid modifications are hypothesized to target proteins to these domains on the cytoplasmic leaflet of the plasma membrane. This concept has now been tested in living cells using an assay sensitive to the lateral distribution of proteins in membranes over sub-micron distances.     

Forging ahead

A large percentage of the world’s population have seen science fiction movies depicting biometric systems that can be circumvented by criminals using sophisticated devices. Such misleading information may prove to be a box office winner, but it can lead to a high amount of confusion about how a biometric device assesses whether a person is who he or she claims to be. While the marketing departments of many biometrics companies address the PR issues associated with inaccurate information, the technical divisions are also working hard to eliminate problems associated with ‘live and well’ checks. However, to my knowledge, in spite of the steps taken by many fingerprint companies, no fingerprint system — currently on the market — is 100% foolproof.     

Peering into tunneling nanotubes—The path forward

The identification of Tunneling Nanotubes (TNTs) and TNT‐like structures signified a critical turning point in the field of cell‐cell communication. With hypothesized roles in development and disease progression, TNTs’ ability to transport biological cargo between distant cells has elevated these structures to a unique and privileged position among other mechanisms of intercellular communication. However, the field faces numerous challenges—some of the most pressing issues being the demonstration of TNTs in vivo and understanding how they form and function. Another stumbling block is represented by the vast disparity in structures classified as TNTs. In order to address this ambiguity, we propose a clear nomenclature and provide a comprehensive overview of the existing knowledge concerning TNTs. We also discuss their structure, formation‐related pathways, biological function, as well as their proposed role in disease. Furthermore, we pinpoint gaps and dichotomies found across the field and highlight unexplored research avenues. Lastly, we review the methods employed to date and suggest the application of new technologies to better understand these elusive biological structures.     

Peering into the birth canal during ion channel parturition

Recent studies have provided detailed structures of the N-terminal T1 domain of Kv channel alpha subunits that mediates contranslational subunit assembly. In this issue of Neuron, Kosolapov et al. probe T1 domain structure within the ribosomal tunnel. They find that the T1 domain forms secondary structure within the tunnel, in preparation for its immediate role in governing channel assembly upon exit.