Entrega em adoção e demanda de reencontro à justiça: motivações da genitora / Voluntary relinquishment and request to justice for reunion: birth mother's motivations / Entrega en adopción y solicitud de reencuentro a la justicia: motivaciones de la madre biológica

Mudanças legislativas em relação à adoção vêm trazendo importantes repercussões para a compreensão do instituto. Neste artigo, temos como objetivo discutir especificidades da entrega voluntária de uma criança para adoção, no contexto da Justiça, e as motivações de demanda posterior da genitora para a viabilização de um reencontro. Problematizamos a amplitude do direito de acesso às origens, assegurado em lei aos adotados, a partir do entrelaçamento das temáticas entrega e reencontro, procurando compreender essas experiências pela perspectiva da genitora. Este trabalho parte de um caso paradigmático, atendido em uma Vara da Infância, Juventude e Idoso no estado do Rio de Janeiro, que culminou com o contato, mediado pelo Poder Judiciário, entre a adotada e sua genitora, por iniciativa desta. Trata-se de um estudo qualitativo, no qual foi realizada uma entrevista semiestruturada com a genitora, quatro anos após o acolhimento de seu pedido à Justiça. Os dados obtidos na entrevista foram analisados por meio do método de análise de conteúdo, em sua vertente categorial, resultando em duas categorias: entrega em adoção e segredos; reencontro: motivações e trajetórias. Constatamos a ausência de publicações brasileiras sobre a temática do reencontro, apontando que o assunto ainda é um tabu. Identificamos que, após o reencontro com a filha, foi possível à genitora uma transformação de si mesma, favorecendo o rompimento do segredo da entrega e de parte de sua história. Assinalamos a necessidade de mais pesquisas, incluindo-se a possibilidade da inserção do Judiciário na mediação dessas demandas.(AU)

Legislative changes related to adoption have brought important repercussions for understanding its regulations. In this article, we aim to discuss the peculiarities of a voluntary relinquishment of a child for adoption, in the context of justice, and the motivations of subsequent demand from the birth mother to set a reunion. We problematize the dimension of the right to access origins, guaranteed by law to adoptees, based on the intertwining of the themes voluntary relinquishment and reunion, seeking to understand these experiences from the perspective of the biological mother. This work is based on a paradigmatic case, attended at a Juvenile Court in the State of Rio de Janeiro, that culminated on the reunion of the adopted and her birth mother, at the initiative of the latter, mediated by the Judiciary. This is a qualitative study, in which we interviewed the biological mother, four years after her legal requirement. The data obtained in the interview were analyzed using the content analysis method, in its categorical aspect, resulting in two categories: voluntary relinquishment in adoption and secrets; reunion: motivations and trajectories. We concluded the absence of Brazilian studies about the theme of reunion, pointing out that the subject still as a taboo. We identified that, after the reunion with the daughter, it was possible for the biological mother to modify herself, favoring the breaking of the secret about the relinquishment and of part of her story. We point out the need of more research, including the possibility of inserting the Judiciary as a mediator for such demands.(AU)

Los cambios legislativos respecto a la adopción han tenido importantes repercusiones en la comprensión de la materia. Este artículo pretende discutir los detalles de la entrega espontánea de un niño para adopción, en el contexto de la Justicia, y las motivaciones de la posterior demanda de la madre biológica para hacer factible un reencuentro. Se problematiza la amplitud del derecho de acceso a los orígenes, garantizado por la ley a los adoptados, a partir del entrelazamiento de los temas entrega y reencuentro, analizando estas experiencias desde la perspectiva de la madre biológica. Este trabajo parte de un caso paradigmático que se llevó a cabo en un Juzgado de la Infancia, Juventud y Persona Mayor del Estado de Río de Janeiro y que culminó en el contacto entre la adoptada y su madre, por iniciativa de esta última, mediado por el Poder Judicial. Este estudio cualitativo realizó una entrevista semiestructurada con la madre biológica cuatro años después de su solicitud a la Justicia. A los datos obtenidos en la entrevista se aplicaron el método de análisis de contenido en su vertiente categórica, en el cual surgieron dos categorías: entrega en adopción y secretos; reencuentro: motivaciones y trayectorias. Se encontró que la falta de estudios brasileños sobre reencuentro apunta a que el concepto del sujeto todavía es un tabú. Se constató que luego del encuentro la madre biológica pasó por una autotransformación, lo que favoreció la ruptura del secreto sobre la entrega y parte de su historia. Es necesario realizar más investigaciones sobre el tema, incluida la posibilidad de insertar al Poder Judicial como mediador de tales demandas.(AU)

Evidence for the preferential reuse of sub-domain motifs in primordial protein folds.

A comparison of protein backbones makes clear that not more than approximately 1400 different folds exist, each specifying the three-dimensional topology of a protein domain. Large proteins are composed of specific domain combinations and many domains can accommodate different functions. These findings confirm that the reuse of domains is key for the evolution of multi-domain proteins. If reuse was also the driving force for domain evolution, ancestral fragments of sub-domain size exist that are shared between domains possessing significantly different topologies. For the fully automated detection of putatively ancestral motifs, we developed the algorithm Fragstatt that compares proteins pairwise to identify fragments, that is, instantiations of the same motif. To reach maximal sensitivity, Fragstatt compares sequences by means of cascaded alignments of profile Hidden Markov Models. If the fragment sequences are sufficiently similar, the program determines and scores the structural concordance of the fragments. By analyzing a comprehensive set of proteins from the CATH database, Fragstatt identified 12 532 partially overlapping and structurally similar motifs that clustered to 134 unique motifs. The dissemination of these motifs is limited: We found only two domain topologies that contain two different motifs and generally, these motifs occur in not more than 18% of the CATH topologies. Interestingly, motifs are enriched in topologies that are considered ancestral. Thus, our findings suggest that the reuse of sub-domain sized fragments was relevant in early phases of protein evolution and became less important later on.

Different Is More: The Value of Finding an Inhabited Planet That Is Far from Earth2.0.

The search for an inhabited planet, beyond our own, is a driver of planetary exploration in our solar system and beyond. Using information from our own planet to inform search strategies allows for a targeted search. It is, however, worth considering some span in the strategy and in a priori expectation. An inhabited, Earth-like planet is one that would be similar to Earth in ways that extend beyond having biota. To facilitate a comparative cost/risk/benefit analysis of different potential search strategies, we use a metric akin to the Earth-similarity index. The metric extends from zero, for an inhabited planet that is like Earth in all other regards (i.e., zero differences), toward end-member values for planets that differ from Earth but maintain life potential. The analysis shows how finding inhabited planets that do not share other Earth characteristics could improve our ability to assess galactic life potential without a large increase in time-commitment costs. Search strategies that acknowledge the possibility of such planets can minimize the potential of exploration losses (e.g., searching for long durations to reach conclusions that are biased). Discovering such planets could additionally provide a test of the Gaia hypothesis-a test that has proven difficult when using only Earth as a laboratory. Finally, we discuss how an Earth2.0 narrative that has been presented to the public as a search strategy comes with nostalgia-laden baggage that does not best serve exploration.

Reduced alphabet of prebiotic amino acids optimally encodes the conformational space of diverse extant protein folds.

BACKGROUND: There is wide agreement that only a subset of the twenty standard amino acids existed prebiotically in sufficient concentrations to form functional polypeptides. We ask how this subset, postulated as {A,D,E,G,I,L,P,S,T,V}, could have formed structures stable enough to found metabolic pathways. Inspired by alphabet reduction experiments, we undertook a computational analysis to measure the structural coding behavior of sequences simplified by reduced alphabets. We sought to discern characteristics of the prebiotic set that would endow it with unique properties relevant to structure, stability, and folding. RESULTS: Drawing on a large dataset of single-domain proteins, we employed an information-theoretic measure to assess how well the prebiotic amino acid set preserves fold information against all other possible ten-amino acid sets. An extensive virtual mutagenesis procedure revealed that the prebiotic set excellently preserves sequence-dependent information regarding both backbone conformation and tertiary contact matrix of proteins. We observed that information retention is fold-class dependent: the prebiotic set sufficiently encodes the structure space of α/ß and α + ß folds, and to a lesser extent, of all-α and all-ß folds. The prebiotic set appeared insufficient to encode the small proteins. Assessing how well the prebiotic set discriminates native vs. incorrect sequence-structure matches, we found that α/ß and α + ß folds exhibit more pronounced energy gaps with the prebiotic set than with nearly all alternatives. CONCLUSIONS: The prebiotic set optimally encodes local backbone structures that appear in the folded environment and near-optimally encodes the tertiary contact matrix of extant proteins. The fold-class-specific patterns observed from our structural analysis confirm the postulated timeline of fold appearance in proteogenesis derived from proteomic sequence analyses. Polypeptides arising in a prebiotic environment will likely form α/ß and α + ß-like folds if any at all. We infer that the progressive expansion of the alphabet allowed the increased conformational stability and functional specificity of later folds, including all-α, all-ß, and small proteins. Our results suggest that prebiotic sequences are amenable to mutations that significantly lower native conformational energies and increase discrimination amidst incorrect folds. This property may have assisted the genesis of functional proto-enzymes prior to the expansion of the full amino acid alphabet.

The Standard Genetic Code can Evolve from a Two-Letter GC Code Without Information Loss or Costly Reassignments.

It is widely agreed that the standard genetic code must have been preceded by a simpler code that encoded fewer amino acids. How this simpler code could have expanded into the standard genetic code is not well understood because most changes to the code are costly. Taking inspiration from the recently synthesized six-letter code, we propose a novel hypothesis: the initial genetic code consisted of only two letters, G and C, and then expanded the number of available codons via the introduction of an additional pair of letters, A and U. Various lines of evidence, including the relative prebiotic abundance of the earliest assigned amino acids, the balance of their hydrophobicity, and the higher GC content in genome coding regions, indicate that the original two nucleotides were indeed G and C. This process of code expansion probably started with the third base, continued with the second base, and ended up as the standard genetic code when the second pair of letters was introduced into the first base. The proposed process is consistent with the available empirical evidence, and it uniquely avoids the problem of costly code changes by positing instead that the code expanded its capacity via the creation of new codons with extra letters.

Predictive regulation and human design.

Organisms evolving toward greater complexity were selected across aeons to use energy and resources efficiently. Efficiency depended on prediction at every stage: first a clock to predict the planet's statistical regularities; then a brain to predict bodily needs and compute commands that dynamically adjust the flows of energy and nutrients. Predictive regulation (allostasis) frugally matches resources to needs and thus forms a core principle of our design. Humans, reaching a pinnacle of cognitive complexity, eventually produced a device (the steam engine) that converted thermal energy to work and were suddenly awash in resources. Today boundless consumption in many nations challenges all our regulatory mechanisms, causing obesity, diabetes, drug addiction and their sequelae. So far we have sought technical solutions, such as drugs, to treat complex circuits for metabolism, appetites and mood. Here I argue for a different approach which starts by asking: why does our regulatory system, which evolution tuned for small satisfactions, now constantly demand 'more'?

Exoplanet Biosignatures: A Framework for Their Assessment.

Finding life on exoplanets from telescopic observations is an ultimate goal of exoplanet science. Life produces gases and other substances, such as pigments, which can have distinct spectral or photometric signatures. Whether or not life is found with future data must be expressed with probabilities, requiring a framework of biosignature assessment. We present a framework in which we advocate using biogeochemical "Exo-Earth System" models to simulate potential biosignatures in spectra or photometry. Given actual observations, simulations are used to find the Bayesian likelihoods of those data occurring for scenarios with and without life. The latter includes "false positives" wherein abiotic sources mimic biosignatures. Prior knowledge of factors influencing planetary inhabitation, including previous observations, is combined with the likelihoods to give the Bayesian posterior probability of life existing on a given exoplanet. Four components of observation and analysis are necessary. (1) Characterization of stellar (e.g., age and spectrum) and exoplanetary system properties, including "external" exoplanet parameters (e.g., mass and radius), to determine an exoplanet's suitability for life. (2) Characterization of "internal" exoplanet parameters (e.g., climate) to evaluate habitability. (3) Assessment of potential biosignatures within the environmental context (components 1-2), including corroborating evidence. (4) Exclusion of false positives. We propose that resulting posterior Bayesian probabilities of life's existence map to five confidence levels, ranging from "very likely" (90-100%) to "very unlikely" (<10%) inhabited. Key Words: Bayesian statistics-Biosignatures-Drake equation-Exoplanets-Habitability-Planetary science. Astrobiology 18, 709-738.

A note on random catalytic branching processes.

A variety of evolutionary processes in biology can be viewed as settings where organisms 'catalyse' the formation of new types of organisms. One example, relevant to the origin of life, is where transient biological colonies (e.g. prokaryotes or protocells) give rise to new colonies via lateral gene transfer. In this short note, we describe and analyse a simple random process which models such settings. By applying theory from general birth-death processes, we describe how the survival of a population under catalytic diversification depends on interplay of the catalysis rate and the initial population size. We also note how such process can also be viewed within the framework of 'self-sustaining autocatalytic networks'.

The enduring value of Gánti's chemoton model and life criteria: Heuristic pursuit of exact theoretical biology.

Gánti's chemoton model of the minimal chemical organization of living systems and life criteria for the living state and a living world are characterized. It is argued that these are better interpreted as part of a heuristic pursuit of an exact theoretical biology than as a "definition of life." Several problems with efforts to define life are discussed. Clarifying the proper use of Gánti's ideas to serve constructive engineering idealizations helps to show their enduring value.

Two fundamental questions about protein evolution.

Two basic questions are considered that approach protein evolution from different directions; the problems arising from using Markov models for the deeper divergences, and then the origin of proteins themselves. The real problem for the first question (going backwards in time) is that at deeper phylogenies the Markov models of sequence evolution must lose information exponentially at deeper divergences, and several testable methods are suggested that should help resolve these deeper divergences. For the second question (coming forwards in time) a problem is that most models for the origin of protein synthesis do not give a role for the very earliest stages of the process. From our knowledge of the importance of replication accuracy in limiting the length of a coding molecule, a testable hypothesis is proposed. The length of the code, the code itself, and tRNAs would all have prior roles in increasing the accuracy of RNA replication; thus proteins would have been formed only after the tRNAs and the length of the triplet code are already formed. Both questions lead to testable predictions.

[On the problems of the evolutionary optimization of life history. I. A Markov model of the Leslie life history and optimization of fertility].

The paper considers the properties of individual life history corresponding to the Leslie model of age-structured population. The life history is simulated as a finite Markov chain with absorption at a death state of individual. In this model, individual longevity, average number of offspring R(L) (produced by an individual over the entire life), and some other known parameters of the life history have been derived using simple probability methods that do not involve matrix calculus and their individual components have been interpreted. In the Leslie linear population model (derived by simple modification of a Markov chain), R(L) determines the growth or decline of a population. Individuals with higher R(L) values have evolutionary advantages in the population due to accelerated growth in their number The selection of fertility as a factor of the increase in R(L) is considered. In the Leslie model, fertility is a set of correlated quantitative traits, where the age-specific fertility components determined both by multipl loci and the environment. According to the genetic theory of quantitative trait selection, they evolve towards an increase in R(L). Taking into account the limited resources for reproduction, selection optimizes the fertility distribution according to age. Optimal distribution corresponds to the attainment of the maximum R(L). This complies with the maximization of the rate of population growth (r-selection), which is characteristic of linear population models. The search for the RL maximum and optimal distribution of fertility belongs to the field of linear programming.

Looking for chemical reaction networks exhibiting a drift along a manifold of marginally stable states.

I recently reported some examples of mass-action equations that have a continuous manifold of marginally stable stationary states [Brogioli, D., 2010. Marginally stable chemical systems as precursors of life. Phys. Rev. Lett. 105, 058102; Brogioli, D., 2011. Marginal stability in chemical systems and its relevance in the origin of life. Phys. Rev. E 84, 031931]. The corresponding chemical reaction networks show nonclassical effects, i.e. a violation of the mass-action equations, under the effect of the concentration fluctuations: the chemical system drifts along the marginally stable states. I proposed that this effect is potentially involved in abiogenesis. In the present paper, I analyze the mathematical properties of mass-action equations of marginally stable chemical reaction networks. The marginal stability implies that the mass-action equations obey some conservation law; I show that the mathematical properties of the conserved quantity characterize the motion along the marginally stable stationary state manifold, i.e. they allow to predict if the fluctuations give rise to a random walk or a drift under the effect of concentration fluctuations. Moreover, I show that the presence of the drift along the manifold of marginally stable stationary-states is a critical property, i.e. at least one of the reaction constants must be fine tuned in order to obtain the drift.

Interactions of iron-sulfur clusters with small peptides: insights into early evolution.

Favoring the stability of iron-sulfur clusters in hydrothermal vents could have been important for the origin of life. It has been postulated that small "nest" peptides with lengths between 3 and 6 residues could have been important to stabilize early iron-sulfur clusters. We present theoretical calculations exploring the sequence and conformational spaces of short peptides able to bind with high affinity the iron-sulfur cluster Fe(4)S(4). Our results indicate that it is unlikely to form stable complexes between Fe(4)S(4) and small peptides at the core of hydrothermal vents. The formation of these complexes is instead favored for peptides of at least 8 residues as they diffused together with the Fe(4)S(4) clusters toward lower temperature regions within the vent-associated temperature gradients.

Biased versus unbiased randomness in homo-polymers and copolymers of amino acids in the prebiotic world.

The polymerization of amino acids under anhydrous prebiotic conditions was first studied several decades ago. Here we use a stochastic model stressing the relevant role of the polarity of amino acids in the formation of oligopeptides in a prebiotic milieu. Our goal is to outline the predominance of co-polypeptides over homo-polypeptides, resulting not only from the randomness, but also from polarity properties of amino acids. Our results conclude that there was a higher probability of the formation of co-polypeptides than of homo-polymers. Besides, we may hypothesize that the former would have a more ample spectrum of possible chemical functions than homo-polypeptides.

Universal sequence replication, reversible polymerization and early functional biopolymers: a model for the initiation of prebiotic sequence evolution.

Many models for the origin of life have focused on understanding how evolution can drive the refinement of a preexisting enzyme, such as the evolution of efficient replicase activity. Here we present a model for what was, arguably, an even earlier stage of chemical evolution, when polymer sequence diversity was generated and sustained before, and during, the onset of functional selection. The model includes regular environmental cycles (e.g. hydration-dehydration cycles) that drive polymers between times of replication and functional activity, which coincide with times of different monomer and polymer diffusivity. Template-directed replication of informational polymers, which takes place during the dehydration stage of each cycle, is considered to be sequence-independent. New sequences are generated by spontaneous polymer formation, and all sequences compete for a finite monomer resource that is recycled via reversible polymerization. Kinetic Monte Carlo simulations demonstrate that this proposed prebiotic scenario provides a robust mechanism for the exploration of sequence space. Introduction of a polymer sequence with monomer synthetase activity illustrates that functional sequences can become established in a preexisting pool of otherwise non-functional sequences. Functional selection does not dominate system dynamics and sequence diversity remains high, permitting the emergence and spread of more than one functional sequence. It is also observed that polymers spontaneously form clusters in simulations where polymers diffuse more slowly than monomers, a feature that is reminiscent of a previous proposal that the earliest stages of life could have been defined by the collective evolution of a system-wide cooperation of polymer aggregates. Overall, the results presented demonstrate the merits of considering plausible prebiotic polymer chemistries and environments that would have allowed for the rapid turnover of monomer resources and for regularly varying monomer/polymer diffusivities.

An information-carrying and knowledge-producing molecular machine. A Monte-Carlo simulation.

The concept called Knowledge is a measure of the quality of genetically transferred information. Its usefulness is demonstrated quantitatively in a Monte-Carlo simulation on critical steps in a origin of life model. The model describes the origin of a bio-like genetic apparatus by a long sequence of physical-chemical steps: it starts with the presence of a self-replicating oligomer and a specifically structured environment in time and space that allow for the formation of aggregates such as assembler-hairpins-devices and, at a later stage, an assembler-hairpins-enzyme device-a first translation machine.

Origin of life. The role of experiments, basic beliefs, and social authorities in the controversies about the spontaneous generation of life and the subsequent debates about synthesizing life in the laboratory.

For centuries the question of the origin of life had focused on the question of the spontaneous generation of life, at least primitive forms of life, from inanimate matter, an idea that had been promoted most prominently by Aristotle. The widespread belief in spontaneous generation, which had been adopted by the Church, too, was finally abandoned at the beginning of the twentieth century, when the question of the origin of life became related to that of the artificial generation of life in the laboratory. This paper examines the role of social authorities, researchers' basic beliefs, crucial experiments, and scientific advance in the controversies about spontaneous generation from the seventeenth to the nineteenth centuries and analyzes the subsequent debates about the synthesis of artificial life in the changing scientific contexts of the nineteenth and early-twentieth centuries. It shows that despite the importance of social authorities, basic beliefs, and crucial experiments scientific advances, especially those in microbiology, were the single most important factor in the stepwise abandoning of the doctrine of spontaneous generation. Research on the origin of life and the artificial synthesis of life became scientifically addressed only when it got rid of the idea of constant smooth transitions between inanimate matter and life and explored possible chemical and physical mechanisms of the specificity of basic molecules and processes of life.