BioEssays

doi: 10.1002/bies.201090055pmid: N/A

doi: 10.1002/bies.201090054pmid: N/A

doi: 10.1002/bies.201090053pmid: N/A

Cover Photograph: Controlling the mitochondrial collective. On pages 958–966 of this issue Emelie Braschi and Heidi McBride draw comparisons between mitochondria and the Borg, a fictional humanoid species from the Star Trek television series. Both entities constitute a unified collective (or interconnected reticulum) where decisions are either made locally within their network (or “hive”) or globally within the “subspace domain”. For mitochondria, local control involves fusion, regulated by distinct GTPases, and fi ssion leading to depolarization of one of the “daughter” mitochondria and hyperpolarization of the other. On the other hand, the reticulum is highly responsive to the subspace domain, taking into account signaling pathways and coupling them with complex cellular transitions including developmental cues, mitosis and apoptosis. The cover photograph shows a photomontage of labeled mitochondria of a COS7 cell on a stellar background.

Moore, Andrew

doi: 10.1002/bies.201090050pmid: 21061453

doi: 10.1002/bies.201090051pmid: N/A

doi: 10.1002/bies.201090052pmid: N/A

Draghia‐Akli, Ruxandra

doi: 10.1002/bies.201000059pmid: 20824656

de Lorenzo, Victor

doi: 10.1002/bies.201000099pmid: 20936643

Gagnidze, Khatuna; Weil, Zachary M.; Pfaff, Donald W.

doi: 10.1002/bies.201000064pmid: 20836091

Expression of sexually dimorphic behaviors critical for reproduction depends on the organizational actions of steroid hormones on the developing brain. We offer the new hypothesis that transcriptional activities in brain regions executing these sexually dimorphic behaviors are modulated by estrogen‐induced modifications of histone proteins. Specifically, in preoptic nerve cells responsible for facilitating male sexual behavior in rodents, gene expression is fostered by increased histone acetylation and reduced methylation (Me), and, that the opposite set of histone modifications will be found in females. Conversely, in ventromedial hypothalamic neurons that are responsible for coordinating female sexual behavior, transcriptional activities in genetic females are fostered by increased histone acetylation and reduced Me, and, further, that the opposite set of histone modifications will be found in males. Thus, these epigenetic events will guarantee that effects of sex hormone exposure during the neonatal critical period will be translated into lasting sex differences in adult reproductive behaviors.

Setchell, Joanna M.; Huchard, Elise

doi: 10.1002/bies.201000066pmid: 20827785

Major histocompatibility complex (MHC)‐associated mate choice is thought to give offspring a fitness advantage through disease resistance. Primates offer a unique opportunity to understand MHC‐associated mate choice within our own zoological order, while their social diversity provides an exceptional setting to examine the genetic determinants and consequences of mate choice in animal societies. Although mate choice is constrained by social context, increasing evidence shows that MHC‐dependent mate choice occurs across the order in a variety of socio‐sexual systems and favours mates with dissimilar, diverse or specific genotypes non‐exclusively. Recent research has also identified phenotypic indicators of MHC quality. Moreover, novel findings rehabilitate the importance of olfactory cues in signalling MHC genes and influencing primate mating decisions. These findings underline the importance to females of selecting a sexual partner of high genetic quality, as well as the generality of the role of MHC genes in sexual selection.