Unser Haushund: Eine Spitzmaus im Wolfspelz? - Wolf-Ekkehard ...

107doubly interesting because of the lessons it teaches us, over and above what Darwin knew, about the domesticationprocess, about the "side effects” of selective breeding, and about the resemblance, which Darwin well understood,between artificial and natural selection.”Dawkins versucht mit diesem Beispiel unter anderem, den Unterschied zwischenkünstlicher und natürlicher Selektion zu verwischen. Zunächst seine allgemeine imGroßen und Ganzen zutreffende Beschreibung des Versuchsaufbaus:"Belyaev and his colleagues (and successors, for the experimental program continued after his death) subjected foxcubs to standardized tests in which an experimenter would offer a cub food by hand, while trying to stroke or fondle it.The cubs were classified into three classes. Class III cubs were those that fled from or [tried to] bit the person. Class IIcubs would allow themselves to be handled, but showed no positive responsiveness to the experimenters. Class I cubs,the tamest of all, positively approached the handlers, wagging their tails and whining. When the cubs grew up, theexperimenters systematically bred only from this tamest class.”Man beachte nun bei seinen folgenden Erklärungen zum Fuchs-Experiment, wie erimplizit und später explizit damit die Makroevolution veranschaulichen will (p. 74):"After a mere six generations of this selective breeding for tameness, the foxes had changed so much that theexperimenters felt obliged to name a new category, the "domesticated elite” class, which were "eager to establishhuman contact, whimpering to attract attention and sniffing and licking experimenters like dogs”. At the beginning ofthe experiment, none of the foxes were in the elite class."Trut et al. (2012, pp. 14/15) relativieren diese Aussage von Dawkins vielleichtinsofern etwas, als sie feststellen, dass schon 10% der Individuen der wildenAusgangspopulation 182 eine sehr geringe Aggressivität zeigten: "A geneticallydetermined polymorphism for the expression of aggressive and fear responses tohumans was revealed in the farmed fox populations. […] Some of the farm foxesmanifested aggressive responses very weakly. About 10% of the farm-foxes weresuch individuals (Fig. 2.2)." 183 Die Abbildung des Rotfuchses oben (mit dem völligrichtigen Hinweis "There are many records of domesticated red foxes and others,but rarely of sustained domestication.)” zeigt, dass bei einzelnen Exemplaren dieVorstufen zur domesticated elite class möglicherweise übersprungen werdenkönnen. Trut et al. schreiben jedoch (2012, pp. 15/16): "It is noteworthy that tamefoxes from the 'elite of domestication', as well as domestic dogs, are able to readhuman social signals (point and gaze cues) and react adequately to them (Hare etal., 2005). The early behavioural elites appeared at the sixth generation selectedfor tameness. Elite in this context means 'impeccable', or tamed to the highestdegree.” 184 Es wäre vielleicht nicht uninteressant zu erfahren, inwieweit der obenabgebildete Rotfuchs in den Armen seines "Herrchens" und zumindest einige dervielen weiteren Beispiele gezähmter Füchse das nicht vielleicht auch schonkonnten. Aber lassen wir diese Frage offen.In nur sechs Generationen kann man jedenfalls nicht mit allzu vielen neuenMutationen rechnen (und Inzuchteffekte schließen die Autoren aus). Bleibt also zunächst nur dervon Trut al al. genannte "genetically determined polymorphism for the expression182 Trut et al. erklären zu ihrer Ausgangspopulation der Farmfüchse (p. 14): "When the domestication experiment was started, the silver fox hadbeen bred in fur farms for more than 50 years. It may be thought that it had overcome the barrier of natural selection during its alienation fromnature, and its caging and breeding in activity, but it had retained the standard phenotype, strict seasonality of biological functions and therelatively wild behaviour (Fig. 2.1).” – Worauf der oben schon zitierte Hinweis folgt: "A genetically determined polymorphism for the expressionof aggressive and fear responses to humans was revealed in the farmed fox populations. There might have been, quite plausibly, suchpolymorphism in the type of defensive responses to humans in the initial natural populations of wolves.”183 Diese Abbildung zeigt einen Silberfuchs im Käfig mit einer zum Kontakt ausgestreckten Hand (Untertitel "This fox shows a weak aggressiveresponse to attempts to touch it").184 Siehe auch Truts Beschreibung von 1999 unterhttp://www.hum.utah.edu/~bbenham/2510%20Spring%2009/Behavior%20Genetics/Farm-Fox%20Experiment.pdf