A quantitative trait locus analysis of personality in wild bighorn sheep

Abstract

Personality, the presence of persistent behav105ioral differences among individuals over time or contexts, potentially has important ecological and evolutionary consequences. However, a lack of knowledge about its genetic architecture limits our ability to understand its origin, evolution, and maintenance. Here, we report on a genome-wide quantitative trait locus (QTL) analysis for two personality traits, docility and boldness, in free-living female bighorn sheep from Ram Mountain, Alberta, Canada. Our variance component linkage analysis based on 238 microsatellite loci genotyped in 310 pedigreed individuals identified suggestive docility and boldness QTL on sheep chromosome 2 and 6, respectively. A lack of QTL overlap indicated that genetic covariance between traits was not modulated by pleiotropic effects at a major locus and may instead result from linkage disequilibrium or pleiotropic effects at QTL of small effects. To our knowledge, this study represents the first attempt to dissect the genetic architecture of personality in a free-living wildlife population, an important step toward understanding the link between molecular genetic variation in personality and fitness and the evolutionary processes maintaining this variation.

Keywords: Animal model; behavioral syndrome; boldness; docility; heritability; temperament.

Fig 1

Corral trap baited with salt used to capture bighorn sheep at Ram Mountain, Alberta, Canada.

Fig 2

LOD scores along the 26 autosomes and the X chromosome for the presence of docility and boldness QTL in the Ram Mountain bighorn sheep population. Dashed horizontal lines depict the genome-wide suggestive (LOD > 1.88) and significant (LOD > 3.31) thresholds. Arrows highlight suggestive QTLs.

Fig 3

LOD scores along chromosomes on which suggestive QTL were detected in the Ram mountain bighorn sheep population. Dashed horizontal lines depict the conservative genome-wide suggestive (LOD > 1.88) and significant (LOD > 3.31) thresholds. The position of microsatellite markers along chromosomes are indicated by triangles along the x axis.