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

109"…delving into the DNA of our closest companions can deliver some tantalizing insights. In 2009 UCLA biologistRobert Wayne led a study comparing the wolf and dog genomes. The finding that made headlines was that dogsoriginated from gray wolves not in East Asia, as other researchers had argued, but in the Middle East. Less noticedby the press was a brief aside in which Wayne and his colleagues identified a particular short DNA sequence, locatednear a gene called WBSCR17, that was very different in the two species. That region of the genome, they suggested,could be a potential target for "genes that are important in the early domestication of dogs." In humans, theresearchers went on to note, WBSCR17 is at least partly responsible for a rare genetic disorder called Williams-Beurensyndrome. Williams-Beuren is characterized by elfin features, a shortened nose bridge, and "exceptionalgregariousness"— its sufferers are often overly friendly and trusting of strangers.After the paper was published, Wayne says, "the number one email we got was from parents of children sufferingfrom Williams-Beuren. They said, Actually our children remind us of dogs in terms of their ability to read behaviorand their lack of social barriers in their behavior." The elfin traits also seemed to correspond to aspects of thedomestication phenotype. Wayne cautions against making one-to-one parallels between domestication genes andsomething as genetically complex as Williams-Beuren. The researchers are "intrigued," he says, and hoping toexplore the connection further.""Seit 1993 ist die genetische Ursache für das WBS [Williams-Beuren-Syndrom]im Detail bekannt: Auf dem siebten Chromosom fehlen mindestens 23nebeneinanderliegende Gene, was eine ganz eigentümliche Mischung vonMerkmalen zur Folge hat" (FAZ Wissen). 189"Übergroße Kontaktfreudigkeit und völlige Arglosigkeit" gehören gemäß dem inder FAZ beschriebenen Fallbeispiel zu den Merkmalen des Syndroms beimMenschen.Oder gemäß Wiki: "Ein auffälliges Merkmal ist die häufige Distanzlosigkeitgegenüber fremden Menschen: Während Regelkinder übliche Phasen desFremdelns durchleben, sind Kinder mit WBS oft durchgehend offene,kontaktfreudige und gesellige Kinder." 190Dass Verlustmutationen bei Haustieren von großem Interesse für die Züchtung seinkönnen, haben wir oben schon wiederholt unterstrichen. Ein weiteres Beispielmöchte ich hier kurz mit Shearman and Wilton aus ihren Review-Artikel von 2011erwähnen:"Loss-of-function mutations in myostatin (MSTN) is a good example of a trait transferrable between species usingcomparative genomics. It causes increased muscle mass in several species, including dogs and horses (see [42] forreview). Heterozygosity for a MSTN mutation has been found to increase racing ability in both whippets and racinghorses [43, 44]." 191187 Die im Folgenden genannte particular short DNA sequence, located near a gene called WBSCR17 ist jedoch nur einer von mehrerenKandidaten. Im Supplement lesen wir zum Thema Discussion of the best hits: "The highest ranked signal falls in a region containing anunknown gene in EntrezGene with high amino acid sequence similarity to a neurotrimin gene (NTM, OMIM: 607938) and an opioid receptor(OPCML, OMIM: 600632; Supplemental Fig. 17). The former is a cell adhesion gene involved in neurite formation and the latter binds opioidalkaloids in the presence of acidic lipids, is generally highly conserved, and is important in stress response. The next strongest signals(Supplemental Fig. 17a-c) are near ryanodine receptor 3 (RYR3, OMIM: 180903), associated with acquired memory, and adenylate cyclase 8(ADCY8, OMIM: 103070)9,10, which is implicated in sensitization to pain in mice and memory formation in humans. Our fourth and fifthstrongest signatures are near a cluster of interleukin family 1 genes (Supplemental Fig. 17d) and a region containing two genes from thecarnosinase dipeptidase family (CNDP1, OMIM 609064 and CNDP2, OMIM 169800; Supplemental Fig. 18). CNDP1 is a neurotransmitterexpressed in the brain, which degrades carnosine, a dipeptide primarily found in muscle tissue, while CNDP2 is a non-specific peptidaseexpressed predominantly in the kidney and liver. Examining FST alone, we found 12 consecutive SNPs in the top 5th percentile for normalizedFST values located at the SLC24A4 gene, a gene whose polymorphisms in humans are associated with hair and eye color11. We observe asingle SNP with a high FST value in the WBSCR17 gene. The deletion of this gene and neighboring genes gives rise to Williams-Beurensyndrome in humans (OMIM: 194050; Supplemental Fig. 16). While outliers of the genome are not necessarily the result of adaptive evolution,we propose the gene regions mentioned above are interesting candidates for loci involved in the phenotypic evolution of dogs from their wolfancestors.” https://www.eeb.ucla.edu/Faculty/Novembre/vonHoldtEtAl2010Nature-s1.pdf (Siehe auch Zitat auf der nächsten Seite.)188 http://ngm.nationalgeographic.com/print/2011/03/taming-wild-animals/ratliff-text189http://www.faz.net/aktuell/wissen/mensch-gene/williams-beuren-syndrom-so-viel-freundlichkeit-ist-nicht-normal-1257656.html (FrankfurterAllgemeine Sonntagszeitung vom 17. 7. 2005, Nr. 28, p. 29.)190 http://de.wikipedia.org/wiki/Williams-Beuren-Syndrom191 J. R. Shearman and A. N. Wilton (2011): Origins of the Domestic Dog and the Rich Potential for Gene Mapping. Genetical ResearchInternational: http://www.hindawi.com/journals/gri/2011/579308/