Primate sociality in evolutionary context

Much work has been done to further our understanding of the mechanisms that underlie the diversity of primate social organizations, but none has addressed the limits to that diversity or the question of what causes species to either form or not form social networks. The fact that all living primates typically live in social networks makes it highly likely that the last common ancestor of living primates already lived in social networks, and that sociality formed an integral part of the adaptive nature of primate origins. A characterization of primate sociality within the wider mammalian context is therefore essential to further our understanding of the adaptive nature of primate origins. Here we determine correlates of sociality and nonsociality in rodents as a model to infer causes of sociality in primates. We found sociality to be most strongly associated with large-bodied arboreal species that include a significant portion of fruit in their diet. Fruits and other plant products, such as flowers, seeds, and young leaves, are patchily distributed in time and space and are therefore difficult to find. These food resources are, however, predictable and dependable when their location is known. Hence, membership in a social unit can maximize food exploitation if information on feeding sites is shared. Whether sociality evolved in the primate stem lineage or whether it was already present earlier in the evolution of Euarchontoglires remains uncertain, although tentative evidence points to the former scenario. In either case, frugivory is likely to have played an important role in maintaining the presence of a social lifestyle throughout primate evolution.     

Molecular evidence of a reed warbler × great reed warbler hybrid ( Acrocephalus scirpaceus × A. arundinaceus) in Belgium

We report on the second case of a reed warbler × great reed warbler hybrid (Acrocephalus scirpaceus and A. arundinaceus). The bird was captured during a standardised ringing session in Belgium in autumn 1999, and fell between the parental species in all measurements. Molecular analyses of two microsatellite loci verified that the bird was a female that had a reed warbler father and a great reed warbler mother.     

同源四倍体高粱与约翰逊草杂交的细胞遗传学研究

对约翰逊草、人工诱变四倍体高粱品系四沈甜及二者杂交种中期Ⅰ染色体构型、后期Ⅰ染色体行为进行了观察,并对花粉育性与结实率关系进行了研究。结果表明：约翰逊草、四沈甜及杂交种的染色体构型分别是：0．49Ⅰ＋15．83Ⅱ＋0．15Ⅲ＋1．60Ⅳ、0．72Ⅰ＋15．23Ⅱ＋0．075Ⅲ十2．15Ⅳ、0．68Ⅰ＋17．00Ⅱ＋0．18Ⅲ＋0．95Ⅳ。双亲及杂交种都是不规则的四倍体遗传群体。约翰逊草与同源四倍体高粱的染色体组间存在一定程度的同源性,杂交容易成功。     

一种抗菌肽和aFGF融合蛋白的构建和表达

利用PCR技术扩增出带有凝血酶Xa因子切割位点的天蚕素蜂毒素杂合肽和aFGF的融合基因,插入大肠杆菌表达载体pET-3c中,构建出表达质粒pET-aF-CM,并转化至大肠杆菌BL21（DE3）中,氨苄青霉素抗性筛选重组转化子。IPTG诱导4h后,以包涵体形式表达的融合蛋白约占菌体总蛋白的17%。将包涵体溶解后透析复性,并利用肝素亲和层析纯化,得到电泳纯的融合蛋白。Western blot分析表明,该蛋白能与aFGF抗体产生免疫反应。MTT法检测显示,融合蛋白具有促3T3Bal/b细胞分裂活性,其比活为1.471×106IU/mg。利用凝血酶Xa因子裂解融合蛋白,可以获得抗菌肽和含凝血酶Xa因子裂解序列的aFGF蛋白。分子筛回收含杂合抗菌肽,抑菌活性检测表明其对大肠杆菌K12D31具有明显抑菌活性。微量稀释法检测结果表明,回收的抗菌肽对大肠杆菌DH5α、大肠杆菌K12D31、沙门氏菌、金黄色葡萄球菌、枯草芽孢杆菌和绿脓杆菌的MIC分别达6.25μg/ml、10μg/ml、2.5μg/ml、1.25μg/ml、0.625μg/ml和5μg/ml。     

Tumour suppression by immune system through stochastic oscillations

The well-known Kirschner-Panetta model for tumour-immune System interplay [Kirschner, D., Panetta, J.C., 1998. Modelling immunotherapy of the tumour-immune interaction. J. Math. Biol. 37 (3), 235-252] reproduces a number of features of this essential interaction, but it excludes the possibility of tumour suppression by the immune system in the absence of therapy. Here we present a hybrid-stochastic version of that model. In this new framework, we show that in reality the model is also able to reproduce the suppression, through stochastic extinction after the first spike of an oscillation.     

Formation of a new hybrid complex via coordination interaction between 5,10,15-tritolyl-20-(4- and 3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin and the α-[MSiW11O39] Keggin-type polyoxometalate (M = Co and Ni)

New complexes based on a coordination interaction between a pyridyl-porphyrin (namely 5,10,15-tritolyl-20-(4-pyridyl)porphyrin, 5,10,15-tritolyl-20-(3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin) and a Keggin-type polyoxometalate (α-[MSiW₁₁O₃₉]⁶⁻, M = Co²⁺ or Ni²⁺) are formed in solution. The formation of these complexes is clearly evidenced by steady-state and time-resolved luminescence measurements. A strong quenching of the porphyrin fluorescence, accompanied by an important shortening of the fluorescence lifetime, is observed upon addition of the POM and formation of the complexes. Using a variant of the Job’s method from the luminescence spectra, the association constants of the complexes have been estimated to be around 10⁶ L mol⁻¹. Paramagnetic ¹H NMR experiments confirm the formation of the complexes. Indeed, in addition to broadenings of the signals, the coordination binding of the POM to the porphyrin induces large high-frequency shifts for the protons of the pyridyl group coordinated to the paramagnetic metal, and low-frequency shifts for all the other resonances.     

Yttrium containing head-on complexes of silico- and germanotungstate: Synthesis, structure and solution properties

Two dimeric head-on complexes of yttrium containing silico- and germanotungstate were isolated from the one-pot reaction of Y(NO₃)₃·6H₂O with the lacunary Na₁₀[MW₉O₃₄]·16H₂O (M = Si and Ge) building blocks in an acetate buffer at pH 4.5. Both polyanions were structurally characterized using various solid-state analytics, such as single-crystal X-ray diffraction, single-crystal X-ray analysis shows that both polyanions crystallize in the monoclinic crystal system (S.G. P2₁/c). FT-IR spectroscopy, or thermogravimetric analysis. The stability of the polyanion in aqueous solution was studied by multinuclear NMR spectroscopy (¹⁸³W, ⁸⁹Y, ²⁹Si, ¹³C, and ¹H). As expected, the ¹⁸³W NMR spectra display six peaks in the intensity ratio of 4:4:2:4:4:4 which indicates that both polyanions exist as dimeric entities in aqueous solution.     

GENOMICS IN THE LIGHT OF EVOLUTIONARY TRANSITIONS

Molecular biology has entrenched the gene as the basic hereditary unit and genomes are often considered little more than collections of genes. However, new concepts and genomic data have emerged, which suggest that the genome has a unique place in the hierarchy of life. Despite this, a framework for the genome as a major evolutionary transition has not been fully developed. Instead, genome origin and evolution are frequently considered as a series of neutral or nonadaptive events. In this article, we argue for a Darwinian multilevel selection interpretation for the origin of the genome. We base our arguments on the multilevel selection theory of hypercycles of cooperative interacting genes and predictions that gene‐level trade‐offs in viability and reproduction can help drive evolutionary transitions. We consider genomic data involving mobile genetic elements as a test case of our view. A new concept of the genome as a discrete evolutionary unit emerges and the gene–genome juncture is positioned as a major evolutionary transition in individuality. This framework offers a fresh perspective on the origin of macromolecular life and sets the scene for a new, emerging line of inquiry—the evolutionary ecology of the genome.     

Heterotachy and tree building: a case study with plastids and eubacteria

The nature of heterotachy at the center of recent controversy over the relative performance of tree-building methods is different from the form of heterotachy that has been inferred in empirical studies. The latter have suggested that proportions of variable sites (p(var)) vary among orthologues and among paralogues. However, the strength of this inference, describing what may be one of the most important evolutionary properties of sequence data, has remained weak. Consequently, other models of sequence evolution have been proposed to explain some long-branch attraction (LBA) problems that could be attributed to differences in p(var). For an empirical case with plastid and eubacterial RNA polymerase sequences, we confirm using capture-recapture estimates and simulations that p(var) can differ among orthologues in anciently diverged evolutionary lineages. We find that parsimony and a least squares distance method that implements an overly simple model of sequence evolution are susceptible to LBA induced by this form of heterotachy. Although homogeneous maximum likelihood inference was found to be robust to model misspecification in our specific example, we caution against assuming that it will always be so.     

UNIDIRECTIONAL INTROGREESION OF A SEXUALLY SELECTED TRAIT ACROSS AN AVIAN HYBRID ZONE: A ROLE FOR FEMALE CHOICE?

Hybridization can be an evolutionary creative force by forming new polyploid species, creating novel genetic variation or acting as conduits of potentially advantageous traits between hybridizing forms. Evidence for the latter is often difficult to find because alleles under positive selection can spread rapidly across a hybrid zone and sweep to fixation. In Western Panama, an avian hybrid zone between two species of manakins in the genus Manacus exists where the unidirectional introgression of bright, yellow plumage into a white population provides evidence for the importance of hybrid zones as conduits of advantageous traits. Several lines of indirect evidence suggest that sexual selection favoring yellow plumage drives this asymmetrical spread, but more direct evidence is lacking. Along the edge of the hybrid zone, both yellow- and white-collared manakins are found in the same mating arenas or leks and compete for the same females ("mixed leks"), providing us with a unique opportunity to understand the dynamics of yellow plumage introgression. We studied these mixed leks to determine whether yellow males have a mating advantage over white males and, if so, whether the mating advantage is driven by male-male interactions, female choice, or both. We found that yellow males mated more than white males, suggesting that sexual selection favoring yellow males can, indeed, explain the spread of yellow plumage. However, we found that this advantage occurred only in mixed leks where the frequency of yellow males is greater than white males. This suggests that the advantage of yellow males may depend on the presence of other yellow males, which may slow the rate of introgression in leks where yellow frequency is low such as in areas where yellow males are beginning to colonize the white population. This, along with the geographic barrier posed by major rivers in the hybrid zone, may initially limit or slow the spread of yellow plumage. Finally, we found that yellow and white males were similar in aggression and body size, and held comparable positions within leks. Because these traits or factors are often important in or dictated by aggressive male-male interactions, these comparisons indicate that male-male interaction is not the primary mechanism for the spread of yellow plumage. However, white and yellow males received similar numbers of courtship visits from females but differed in the number of matings, suggesting that females actively rejected white in favor of yellow males. Our results indicate that sexual selection by female choice has driven the unidirectional introgression of yellow plumage into the white population, providing a mechanism for how hybrid zones act as conduits of novel and advantageous traits.