African Journal of Biotechnology Vol. 6 (8), pp. 967-970, 16 April 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Comparative genome analysis of trypanotolerance QTL

Joseph Nganga^1,2*, Mabel Imbuga² and Fuad A. Iraqi³

¹International Livestock Research Institute, P. O. Box 30709, Nairobi, Kenya,

²Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, Kenya,

³Department of Human Microbiology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.

*Corresponding author.  E-mail: kangethenganga@yahoo.com/ jnganga@wrp-ksm.org

Accepted 10 April, 2007

Certain breeds of domestic ruminants show remarkable resistance to the effects of African trypano-somosis. Unlike susceptible animals, trypanotolerant animals control parasitemia and do not show severe anaemia or production loss. Identification of trypanotolerance genes in cattle is hampered by cost and breeding time. Marked differences between inbred strains of mice in their response to T. congolense infection can be exploited in the analysis of the genetic basis of the infection. Murine trypanotolerance QTLs have been identified on chromosome 17, 5 and 1, and designated as Tir1, 2 and 3, respectively. Tir1 and 2 have been fine mapped to a confidence interval of 1 cM. In order to find the mouse homologous region on the bovine genome, nucleotide sequence across 95% CI of Tir2 and 3 were used in the selection of candidate genes. Homologous sequences were used in the definition of synteny relationships and subsequent identification of the shared disease response genes. The homologous genes within the human genome were then identified and aligned to the bovine radiation hybrid map in order to identify the mouse/bovine homologous regions. This revealed homology between murine and bovine QTL on Tir3 while the region on Tir2 is linked to innate immune response.

Key words: Trypanosomosis, quantitative trait loci, homology.