1. ¹Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
2. ²Key Laboratory of Nerve Regeneration, Nantong University, Nantong, China
3. ³Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
4. ⁴Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
5. ⁵Departments of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, MO, USA

Correspondence: Dr H Dong, Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660 S Euclid Avenue, St Louis, MO 63110, USA. E-mail: dongh@wustl.edu

Received 2 May 2006; Revised 27 February 2007; Accepted 28 February 2007; Published online 4 April 2007.

Abstract

To investigate whether there are separate or shared genetic influences on the development of the thalamus and cerebral cortex, we identified quantitative trait loci (QTLs) for relevant structural volumes in BXD recombinant inbred (RI) strains of mice. In 34 BXD RI strains and two parental strains (C57BL/6J and DBA/2J), we measured the volumes of the entire thalamus and cortex gray matter using point counting and Cavalieri's rule. Heritability was calculated using analysis of variance (ANOVA), and QTL analysis was carried out using WebQTL (http://www.genenetwork.org). The heritability of thalamus volume was 36%, and three suggestive QTLs for thalamus volume were identified on chromosomes 10, 11 and 16. The heritability of cortical gray matter was 43%, and four suggestive QTLs for cortex gray matter volume were identified on chromosomes 2, 8, 16 and 19. The genetic correlation between thalamus and cortex gray matter volumes was 0.64. Also, a single QTL on chromosome 16 (D16Mit100) was identified for thalamus volume, cortex gray matter volume and Morris water maze search-time preference (r=0.71). These results suggest that there are separate and shared genetic influences on the development of the thalamus and cerebral cortex.