The History of Farm Foxes Undermines the Animal Domestication Syndrome

The Russian Farm-Fox Experiment is the best known experimental study in animal domestication. By subjecting a population of foxes to selection for tameness alone, Dimitry Belyaev generated foxes that possessed a suite of characteristics that mimicked those found across domesticated species. This \u27domestication syndrome\u27 has been a central focus of research into the biological pathways modified during domestication. Here, we chart the origins of Belyaev\u27s foxes in eastern Canada and critically assess the appearance of domestication syndrome traits across animal domesticates. Our results suggest that both the conclusions of the Farm-Fox Experiment and the ubiquity of domestication syndrome have been overstated. To understand the process of domestication requires a more comprehensive approach focused on essential adaptations to human-modified environments

A model for understanding the evolution of mammalian behavior

Unlike reptiles, who are born with species-specific morphology and behavior that hardly changes as they grow into adults, mammals are born with a class-specific neonatal phase that renders the morphology and behavior of each species different from the physiology and behavior of their species-specific adulthood. Mammals must undergo a transformation phase, called youth, between the neonate and the adult. This youthful metamorphic and meta-behavioral phase is necessary while the mammal is remodeling from sucking milk to munching grass or hunting meat. During its youthful phase a mammal is not simply growing linearly into its adult form and behavior but is a hybrid trying out different patterns of neonatal and adult micro-motor pieces of behavior that change almost daily in frequency as pieces of neonatal behavior inactivate and adult behavioral motor pieces begin to activate. The offsets of neonatal behavior and the onsets of species-specific adult behavior drive the youthful mammals into varied combinations of behavior sequences, that, since they are hybrids of two very different systems, don\u27t look functional and are often unusual enough to amuse an observer. Such random hybrid combinations of micromotor pieces of behavior are commonly called play. But, then, play is not a unitary drive as many researchers have assumed but the consequence of youths hybridizing between neonatal and adult behaviors that are waning and waxing in intensity and frequency at each successive stage of youthful ontogeny. During the youthful period, any random combination of motor sequences that are useful for any reason can be remembered, repeated, and learned, so the youthful phase of mammalian ontogeny has potential for learning. A fixed neonatal system of physiological adaptations and complex behaviors is built into the neonate and might be modified for the worse by learning at this stage of its ontogeny. At a mammal\u27s species-specific adult stage it is presumably well adapted to a stable niche. So, again, at this phase of ontogeny learning might be unnecessary. However, during its youthful transition phase a mammal is shifting between two systems of physiology and behavior designed to fit two very different stable environments. Thus its abilities and motives are in constant flux and trial and error learning is perhaps its best means of adjusting to almost daily changes in its own physiology and behavior. The environment of many adult mammals has been changing fast, during the past two and a half million years of successive glaciations and melting with new niches opening and old niches disappearing or degrading. Learning provides a way of coping with swiftly changing environments, and the fastest and most efficient means of providing adult mammals some more learning ability, and a somewhat less fixed and invariable species-specific behavior system would have been a selection for extending the youthful learning phase of mammalian ontogeny into adulthood. An extension of the youthful phase into the adult phase would likely have also loosened the typical species-specific sequences that would have been, in ancestral adults, a fixed system of invariable sequences that fit them to a formerly stable environment. A number of mammalian species and even some orders, such as Primates, probably Cetaceans, and including many Carnivores have, by an evolutionary process of neoteny, retained into adulthood some of their youthful phase of ontogeny. Such an adaptation provided these more neotenic adults a more open system of learning that could modify remnants of ancestral species-specific behavior to better fit adults of that species to a swiftly changing environment. We hypothesize an interesting phenomenon in mammalian phylogeny: that a number of mammalian species have been modified over the past several million years by selection for the metamorphic phase of ontogeny extended into the adult phase. Mammalian phylogeny appears to be recapitulating a reversal in the usual direction of ontogeny

Forever young: upon reading Growing Young by Ashley Montagu

We argue that the evolutionary process of neoteny -- the natural selection of regulatory gene mutations that retain a youthful ontogenetic system of physiological and behavioral characteristics, and thus never activates the full species-specific features of the ancestors’ adulthood. The resulting new behavio-morph retains infant/young features throughout ontogeny and never displays the adult behavior or physiology of the adult ancestor. This kind of neotenic adulthood defines the human character. We not only inherit our ancestors’ youthful anatomy and physiology but the ancestors’ youthful motivations and proclivities such as docility and social dependency, curiosity and learning as well. We retain our ancestors’ youthful small teeth, and we continue to play throughout adulthood. Like young, but unlike most adult mammals, humans continue throughout life to crave attention, play, learn and remain curious whether just for social gossip or for scientific research

Variation in reproductive traits of members of the genus Canis with special attention to the domestic dog (Canis familiaris)

We compare differences in the reproductive strategies of “free-living” dogs with their wild relatives in the genus Canis, of which the dog is a very recently evolved member. The members of this genus display a greater range of parental motor patterns than generally seen in other species of Carnivora, including pair-bonding and extended parental care; parents regurgitate to offspring and provision them with food for months to as long as a year. But the domestic dog does not routinely display these genustypical behaviors. While this has generally been assumed to be a result of direct human intervention, humans have little reproductive control over the vast majority of domestic dogs. We analyze the low frequency of display of genus-typical behaviors and postulate that the dog’s reproductive behaviors are an adaptation to permanent human settlement and the waste resources associated with it. Adaptation to this environment has decreased seasonality, increased the fecundity of unrestrained dogs and reduced the need for prolonged parental care. The consequences of greater fecundity and reduced parental care are compared to the reproductive behavior of other species of the genus

Blood platelets and sepsis pathophysiology: A new therapeutic prospect in critical ill patients?

Beyond haemostasis, platelets have emerged as versatile effectors of the immune response. The contribution of platelets in inflammation, tissue integrity and defence against infections has considerably widened the spectrum of their role in health and disease. Here, we propose a narrative review that first describes these new platelet attributes. We then examine their relevance to microcirculatory alterations in multi-organ dysfunction, a major sepsis complication. Rapid progresses that are made on the knowledge of novel platelet functions should improve the understanding of thrombocytopenia, a common condition and a predictor of adverse outcome in sepsis, and may provide potential avenues for management and therapy