Citation: Tancredi, D.; Cardinali, I. Being a Dog: A Review of the Domestication Process. Genes 2023, 14, 992. https://doi.org/10.3390/ genes14050992 Academic Editors: Benjamin N. Sacks and Manuel Ruiz-Garcia Received: 8 March 2023 Revised: 19 April 2023 Accepted: 26 April 2023 Published: 27 April 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). genes G C A T T A C G G C A T Review Being a Dog: A Review of the Domestication Process Domenico Tancredi and Irene Cardinali * Department of Chemistry, Biology and Biotechnology, Università degli Studi di Perugia, 06123 Perugia, Italy; domenicotancredi94@gmail.com * Correspondence: cardinali_irene@libero.it Abstract: The process of canine domestication represents certainly one of the most interesting ques- tions that evolutionary biology aims to address. A “multiphase” view of this process is now accepted, with a first phase during which different groups of wolves were attracted by the anthropogenic niche and a second phase characterized by the gradual establishment of mutual relationships between wolves and humans. Here, we provide a review of dog (Canis familiaris) domestication, highlighting the ecological differences between dogs and wolves, analyzing the molecular mechanisms which seem to have influenced the affiliative behaviors first observed in Belyaev’s foxes, and describing the genetics of ancient European dogs. Then, we focus on three Mediterranean peninsulas (Balkan, Iberian and Italian), which together represent the main geographic area for studying canine domes- tication dynamics, as it has shaped the current genetic variability of dog populations, and where a well-defined European genetic structure was pinpointed through the analysis of uniparental genetic markers and their phylogeny. Keywords: dog; Canis familiaris; domestication; wolves; mitochondrial DNA; Y chromosome; Mediterranean area 1. Introduction Domestication represents the evolutionary process in which the genetic, physiological, and behavioral (and cognitive) profile of a species is reshaped to adapt to a man-made environment. It arises from mutualism between two species, where the domesticator creates an environment and actively manages both the survival and reproduction of another species (the domesticated), which provides the former with resources and/or services [1]. The selective pressures involved in domestication are likely to have varied over time and across taxa, although it is believed that in many species, the early stages of this process were largely dependent on the evolutionary reduction of fear and aggression toward humans [2]. The domestication of plants and animals represents undoubtedly one of the greatest achievements mankind has ever made, as the cultivation of “selected” plant species enabled humans to increase their food supply, while the domestication of animal species made it easier to perform diversified tasks, such as hunting and managing cultivated land. The domestication of surrounding flora and fauna by ancient human populations required an intentionality and an understanding of other species’ behavior and reproductive biology [3,4]; thus, the cognitive demands of the human-mediated domestication process constitute a phenomenon distinct from other interspecific mutualisms, i.e., those evolved by social insects [5,6]. The massive domestication of plants and animals by humans was likely triggered by the significant climatic and environmental changes that characterized the global transition from the Last Glacial Maximum (LGM) to the current Holocene interglacial period [7]. The demographic pressure produced by the exponential growth of the human population was proposed as a random factor favoring domestication, since it produced an increase in relationships between humans and animals. Genes 2023, 14, 992. https://doi.org/10.3390/genes14050992 https://www.mdpi.com/journal/genes