Mitogenomic analysis of extant condor species provides insight into the molecular evolution of vultures

The evolution of large vultures linked to mountainous habitats was accompanied by extreme physiological and behavioral specializations for energetically efficient flights. However, little is known on the genetic traits associated with the evolution of these obligate soaring scavengers. Mitochondrial DNA plays a vital role in regulating oxidative stress and energy production, and hence may be an important target of selection for flight performance. Herein, we characterized the first mitogenomes of the Andean and California condors, the world’s heaviest flying birds and the only living representatives of the Vultur and Gymnogyps genus. We reconstructed the phylogenetic relationships and evaluated possible footprints of convergent evolution associated to the life-history traits and distributional range of vultures. Our phylogenomic analyses supported the independent evolution of vultures, with the origin of Cathartidae in the early Paleogene (~ 61 Mya), and estimated the radiation of extant condors during the late Miocene (~ 11 Mya). Selection analyses indicated that vultures exhibit signals of relaxation of purifying selection relative to other accipitrimorph raptors, possibly indicating the degeneration of flapping flight ability. Overall, our results suggest that the extreme specialization of vultures for efficient soaring flight has compensated the evolution of large body sizes mitigating the selection pressure on mtDNA.

Mitogenomic analysis of extant condor species provides insight into the molecular evolution of vultures

The evolution of large vultures linked to mountainous habitats was accompanied by extreme physiological and behavioral specializations for energetically efficient flights. However, little is known on the genetic traits associated with the evolution of these obligate soaring scavengers. Mitochondrial DNA plays a vital role in regulating oxidative stress and energy production, and hence may be an important target of selection for flight performance. Herein, we characterized the first mitogenomes of the Andean and California condors, the world’s heaviest flying birds and the only living representative of Vultur and Gymnogyps genus. We reconstructed the phylogenetic relationships and evaluated possible footprints of convergent evolution associated to the life-history traits and distributional range of vultures. Our phylogenomic analyses supported the independent evolution of vultures, with the origin of Cathartidae in the early Paleogene (~ 59 Mya), and estimated the radiation of extant condors during the late Miocene (~ 10 Mya). Selection analyses indicated that vultures exhibit signals of relaxation of purifying selection relative to other accipitrimorph raptors, possibly indicating the degeneration of flapping flight ability. Overall, our results suggest that the extreme specialization of vultures for efficient soaring flight has compensated the evolution of large body sizes mitigating the selection pressure on mtDNA.

Specialization of the cloacal microbiome relative to gut, oviduct, and feces of an oviparous lizard

Microbial diversity and community function are related, and both can be highly specialized in different regions of the gut. The cloacal microbiome of Sceloporus virgatus lizards has low diversity, suggesting a specialized function, and is known to transfer antifungal microbes to eggshells during oviposition. We hypothesize that the cloacal microbiome is distinct from other parts of the digestive and reproductive systems. Here, we compare the microbiome of tissue samples from the cloaca, lower intestine, upper intestine, and oviduct. We further assessed whether common methods of microbial sampling – cloacal swabs and feces – provide accurate representations of these tissues, and whether feces might “seed” the cloacal microbiome. We found that the upper intestine and oviduct had unique microbial communities, while the lower intestine and cloaca had similar communities with lower diversity indicative of regional specialization. The cloacal community, in particular, showed extreme specialization averaging 99% Proteobacteria (Phylum) and 83% Enterobacteriacaea (Family). Cloacal swabs recovered communities similar to that of lower intestine and cloacal tissues, but fecal samples had much higher diversity and a distinct composition (62% Firmicutes and 39% Lachnospiraceae) relative to all gut regions. This result serves as a caution against the frequent assumption that fecal samples provide an accurate representation of the gut. Finally, we found that defecation did not alter the cloacal microbiome, suggesting that community is robust to perturbations from transient microbiota.

Lifecycle

How many kinds of tasks does a typical em worker regularly do in the course of their job? Looking at job performance today, we see that while extreme specialization can give maximum productivity in the short run, over a longer time a modest degree of task variation is often more productive, because of improved learning and engagement ( Staats and Gino 2012 ). Ems add an important new consideration to this usual tradeoff between task specialization and task variety. Whereas human minds have a limited rate at which they can do tasks, em minds can run at different speeds. So the limited subjective career length of an em can be spent either on more scope in tasks or on more scope in time. That is, an em worker can either run faster and simultaneously do and coordinate more related tasks, or it can run slower and coordinate fewer tasks over a longer period of time, and improve at those tasks in the process. Some tasks require a continual response to external drivers. These tasks include managing physical systems, such as driving cars. Such tasks usually require mental response times as fast as the slower of two rates: the rate at which outside disturbances arise to which it is useful to respond, and the rate at which the managed system such as a car is capable of responding to such disturbances. When choosing between mind speeds faster than this minimum response rate, one of the main tradeoff s is between getting really good at each task, and coordinating more related tasks. One can either do a more specific task more times over a longer narrower career, or do a wider range of related tasks over a shorter career. During either sort of career one could split off many spurs to do short-term tasks that do not need to be well remembered. Long, narrow careers can achieve high levels of competence while adapting to changing job detail, but require expensive communication between workers to coordinate related tasks. In contrast, having the same worker do a wider range of tasks allows for flexible coordination without communication across those tasks, but comes at the cost of more transitions for each worker between different tasks (Wout et al. 2015), and often lower competence because of less task specialization and a shorter career.

Escape from extreme specialization: passionflowers, bats and the sword-billed hummingbird

A striking example of plant/pollinator trait matching is found between Andean species of Passiflora with 6–14-cm-long nectar tubes and the sword-billed hummingbird, Ensifera ensifera , with up to 11-cm-long bills. Because of the position of their anthers and stigmas, and self-incompatibility, these passionflower species depend on E. ensifera for pollination. Field observations show that the bird and plant distribution match completely and that scarcity of Ensifera results in reduced passionflower seed set. We here use nuclear and plastid DNA sequences to investigate how often and when these mutualisms evolved and under which conditions, if ever, they were lost. The phylogeny includes 26 (70%) of the 37 extremely long-tubed species, 13 (68%) of the 19 species with tubes too short for Ensifera and four of the seven bat-pollinated species for a total of 43 (69%) of all species in Passiflora supersection Tacsonia (plus 11 outgroups). We time-calibrated the phylogeny to infer the speed of any pollinator switching. Results show that Tacsonia is monophyletic and that its stem group dates to 10.7 Ma, matching the divergence at 11.6 Ma of E. ensifera from its short-billed sister species. Whether pollination by short-billed hummingbirds or by Ensifera is the ancestral condition cannot be securely inferred, but extremely long-tubed flowers exclusively pollinated by Ensifera evolved early during the radiation of the Tacsonia clade. There is also evidence of several losses of Ensifera dependence, involving shifts to bat pollination and shorter billed birds. Besides being extremely asymmetric—a single bird species coevolving with a speciose plant clade—the Ensifera / Passiflora system is a prime example of a specialized pollinator not driving plant speciation, but instead being the precondition for the maintenance of isolated populations (through reliable seed set) that then underwent allopatric speciation.

Technological and Market related Capabilities and Competitiveness in the Brazilian Computer Industry: a case study

DOI: http://dx.doi.org/10.13071/regec.2317-5087.2013.2.2.4555.9-31The Brazilian local computer producers have the largest market share, even competing with large global players. This article objective is to discuss how the national private enterprises can compete in complex markets, accumulating not only technological competences but non technological ones. First, the technological paradigm theory allows dividing the computer industry in two groups: the enterprises that control the paradigm core and then push forward the technological frontier; and the enterprises whose competences encompass the secondary paradigm elements. Second, thePositivo’s analyses shows that this enterprise’s competitiveness isn’t connected to its technological competences. Also the elements that keep the local industry competitive are related to the population income expansion experienced in Brazil and due to the enterprise extreme specialization in the lower income population. It is concluded that the Brazilian computer industry can be competitive without accumulation technological competences.