Genetic Architecture of Tameness in a Rat Model of Animal Domestication

Department of Genetics and Pathology, Uppsala University, 75123 Uppsala, Sweden.
Genetics (Impact Factor: 5.96). 05/2009; 182(2):541-54. DOI: 10.1534/genetics.109.102186
Source: PubMed


A common feature of domestic animals is tameness-i.e., they tolerate and are unafraid of human presence and handling. To gain insight into the genetic basis of tameness and aggression, we studied an intercross between two lines of rats (Rattus norvegicus) selected over >60 generations for increased tameness and increased aggression against humans, respectively. We measured 45 traits, including tameness and aggression, anxiety-related traits, organ weights, and levels of serum components in >700 rats from an intercross population. Using 201 genetic markers, we identified two significant quantitative trait loci (QTL) for tameness. These loci overlap with QTL for adrenal gland weight and for anxiety-related traits and are part of a five-locus epistatic network influencing tameness. An additional QTL influences the occurrence of white coat spots, but shows no significant effect on tameness. The loci described here are important starting points for finding the genes that cause tameness in these rats and potentially in domestic animals in general.

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    • "Determining this will require detailed genetic analysis of the condition and preferably in several species, given our prediction that multiple and diverse neural crest cell genes might be involved. Recent progress in mapping the genes involved in domestication in the rat, fox, and dog lay the groundwork by providing a short list of candidate genes and as yet uncharacterized loci for testing our hypothesis (Albert et al. 2009; Kukekova et al. 2010; Vonholdt et al. 2010). "
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    • "). Genotypes, genetic markers, marker positions and pedigree data were the same as for the QTL mapping of tameness described previously in (ALBERT et al. 2009). The probability of each F2 allele to originate from either the tame or the aggressive line were re-computed using an updated algorithm where haplotypes and missing marker information were inferred iteratively in order to reconstruct any missing genotypes. First, haplotypes were inferred from genotype and pedigree data with a custom im"
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    • "Compared to inbred line-based gene mapping, our system offers some additional advantages. First, while the F2 generation could be subjected to conventional linkage mapping [47], the two lines have accumulated ~60 generations of historical recombination (~30 as the NIH Heterogeneous Stock, 28 generations of divergent selection, and F2 intercross). Consequently, animals in both lines carry fine-grained genomic mosaics of eight "ancestral" inbred strains, with LD structure on the order of 3 Mb, allowing for greater resolution in association analysis [48–50]. "
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