Intensive human contact correlates with smaller brains: differential brain size reduction in cattle types

Cattle are one of the most intensively bred domestic animals, providing humans with a multitude of products and uses. Using data from the fossil record, we test if their domestication, as for other taxa, has resulted in a reduction of their brain size. We not only conclude that Bos taurus (domestic cattle) have smaller brains than their wild ancestor, Bos primigenius (aurochs), but that brain size varies significantly by breed, with some having much smaller brains than others. Differences in husbandry practices between several breed categories align with a range of human engagement, which also aligns with the degree of selection for docility. Sampling 317 domestics from 71 breeds, we investigate if differences in brain size correlate with the intensity of human contact. A clear pattern emerges whereby a brain reduction gradient parallels a gradient in behavioural selection. Bullfighting cattle, which are bred for fighting and aggressive temperament, have much larger brains than dairy breeds, which are intensively selected for docility. Our results add to a fundamental aspect of animal domestication theory: the interplay between basic features of the domestic environment—selection for docility, absence of predators and human provision of resources—seems to explain differences in brain size.

Structural variants selected during yak domestication inferred from long-read whole-genome sequencing

Structural variants (SVs) represent an important genetic resource for both natural and artificial selection. Here we present a chromosome-scale reference genome for domestic yak (Bos grunniens) that has longer contigs and scaffolds (N50 44.72Mb and 114.39 Mb, respectively) than reported for any other ruminant genome. We further obtained long-read resequencing data for 6 wild and 23 domestic yaks and constructed a genetic SV map of 37,220 SVs that covers the geographic range of the yaks. The majority of the SVs contains repetitive sequences and several are in or near genes. By comparing SVs in domestic and wild yaks, we identified genes that are predominantly related to the nervous system, behavior, immunity and reproduction and may have been targeted by artificial selection during yak domestication. These findings provide new insights in the domestication of animals living at high altitude and highlight the importance of SVs in animal domestication.

Archaeogenomics of Animal Domestication in Eurasia

The processes of domestication and subsequent distribution of animals in Eurasia are closely related to human migrations and intercultural exchanges starting from the end of the Pleistocene. The development of methods for the isolation and analysis of ancient DNA from archaeological and paleontological remains has made it possible to take a new look at both the presumed core regions of domestication and the geography and dynamics of livestock distribution. This paper discusses the reports on the reconstruction of the migration processes of domestic animals in Eurasia using the analysis of ancient DNA performed by leading specialists from Great Britain, France, Finland, Ireland, and Russia at the international symposium on Domestic Animal Archaeogenomics (Bolgar, Republic of Tatarstan, March 2020). In addition to discussing the demographic history of different species of domestic animals, special attention was given to the development of methods for working with ancient DNA and the peculiarities of sample storage and handling. Summarizing the results of the symposium, the authors identified priority areas for future research. The interdisciplinary nature of research and the need to create broad scientific network that includes specialists from different fields were emphasized.

The Ethics of Farm Animal Biotechnology from an Anthropological Perspective

Over the past 11,000 years, humans have domesticated a wide range of animals for different purposes designed to serve the human economy, society, and religious activities. The resulting mutual dependence between humans and their domestic partners created anthropogenic landscapes designed to sustain and protect their members. In this paper, we review the literature on the latest insights in interdisciplinary anthropological research on the evolution of animal domestication and breeding and put them in the context of the contemporary ethical debate on animal welfare and the application of modern biotechnology to animal breeding. Opponents of the use of animal biotechnology tend to see breeders often as enablers of industrial farming that would seek selective business advantage at the expense of the environment and animal welfare. Many applications of animal biotechnology may, however, also help to address environmental and animal welfare concerns in an effective way. Moreover, recent archeological and genetic research findings on the history of animal domestication reveal a distinctive kind of mutualism in the human–animal relationship based on a gradual co-evolutionary process with clear benefits for both parties in the relationship. These insights challenge the popular Neo-Darwinian account of unilateral adaptation only benefiting the more powerful party. Instead, they support the hypothesis that humans do not just adapt, but actively shape the environment through cultural niche construction (CNC) that also involves care and protection for domesticated animals. These empirical findings should also be taken into account in the contemporary ethical debate on animal welfare, which has become increasingly detached from the real-world efforts to improve animal welfare through best practices.

Infection threat shapes our social instincts

We social animals must balance the need to avoid infections with the need to interact with conspecifics. To that end we have evolved, alongside our physiological immune system, a suite of behaviors devised to deal with potentially contagious individuals. Focusing mostly on humans, the current review describes the design and biological innards of this behavioral immune system, laying out how infection threat shapes sociality and sociality shapes infection threat. The paper shows how the danger of contagion is detected and posted to the brain; how it affects individuals’ mate choice and sex life; why it strengthens ties within groups but severs those between them, leading to hostility toward anyone who looks, smells, or behaves unusually; and how it permeates the foundation of our moral and political views. This system was already in place when agriculture and animal domestication set off a massive increase in our population density, personal connections, and interaction with other species, amplifying enormously the spread of disease. Alas, pandemics such as COVID-19 not only are a disaster for public health, but, by rousing millions of behavioral immune systems, could prove a threat to harmonious cohabitation too.

Infection threat shapes our social instincts

We social animals must balance the need to avoid infections with the need to interact with conspecifics. To that end we have evolved, alongside our physiological immune system, a suite of behaviors devised to deal with potentially contagious individuals. Focusing mostly on humans, the current review describes the design and biological innards of this behavioral immune system, laying out how infection threat shapes sociality and sociality shapes infection threat. The paper shows how the danger of contagion is detected and posted to the brain; how it affects individuals’ mate choice and sex life; why it strengthens ties within groups but severs those between them, leading to hostility toward anyone who looks, smells, or behaves unusually; and how it permeates the foundation of our moral and political views. This system was already in place when agriculture and animal domestication set off a massive increase in our population density, personal connections, and interaction with other species, amplifying enormously the spread of disease. Alas, pandemics such as COVID-19 not only are a disaster for public health, but, by rousing millions of behavioral immune systems, could prove a threat to harmonious cohabitation too.