Effects of a Chicken Growth QTL on Behaviour are due to Linkage rather than Pleiotropy
(English)Manuscript (preprint) (Other academic)
earlier studies, we have found pleiotropic effects of a growth QTL in chickens on behavioural traits that have changed as a result of domestication. In this study we performed a) a refined analysis of the QTL in an advanced intercross line between Red Junglefowl (RJF) and White Leghorn layers (WL) to investigate if different behavioural and physiological traits are associated with different regions of the QTL, and b) brain gene expression analysis (using qRT-PCR) in RJF and WL, comparing the expression between breeds of a number of genes within the growth QTL that may be considered candidates for affecting behavioural traits. The refined QTL analysis was performed on 62 birds from a selected line corresponding to the F7 generation of an RJF×WL intercross (SAIL). The gene expression analysis was performed on 12 RJF and 10 WL birds. In addition to recording of weight data, the SAIL birds were exposed to a behavioural test measuring aspects of sociality and emotionality. The QTL analysis found a significant association between body weight at 8 days of age and a 1.7 MB region in the QTL, and a suggestive association between emotionality related behaviours and a different part, 7.5 MB large, of the QTL. The gene expression analysis showed differential expression of AVPR2 (receptor for vasotocin), possibly AVPR1a (another vasotocin receptor) and NRCAM (involved in neural development) in the lower frontal lobes of the brains of RJF and WL birds. It therefore seems that linkage of several different genes affecting different traits, rather than pleiotropy of one or a few, may explain the many effects of this QTL, and that AVPR2, AVPR1a and NRCAM cannot be discarded as candidate genes for the observed effects.
IdentifiersURN: urn:nbn:se:liu:diva-73984OAI: oai:DiVA.org:liu-73984DiVA: diva2:479673