From QTL to candidate genes - an example from QTL mapping for trypanosomosis resistance in cattle

Tsetse-transmitted trypanosomosis is the most important disease constraint to livestock productivity in subSaharan Africa. It is endemic to 7 million km2 with 60 millions cattle at risk of infection. Some breeds of indigenous African cattle, most notably the West African taurine (e.g. N'Dama), have been reported to tolerate trhypanosomosis infection. Improvement and greater exploitation of their genetic resistance is regarded as a sustainable long-term solution to control the impact of the disease on livestock productivity. Following a genome wide scan in an F2 cross between the trypanotolerant N'Dama Bos taurus from The Gambia and the trypanosusceptible Kenya Boran B. indicus, a trypanosomosis resistance QTL controlling parasitaemia was mapped on chromosome 7 (Bta07). A combination of chromosome-microdissection, comparative, radiation hybrid and physical mapping techniques, were exploited to isolate and to order new markers as well as to identify putative candidates genes for trypanotolerance within the Bta07 QTL region. At least nine candidate genes were identified. Amongst these, two (HNRPM4, PGAR) were mapped in the newly found region of homology between the trypanosomosis resistance QTL region on Bta07 and a trypanosomosis resistance QTL on Mmu17. These candidate genes are implicated in innate immunity through participation in effector signalling pathways (ECSIT, MAP2K7, ACP5); regulation of gene expression and RNA processing (ELAVL1, EIF3S4, HNRPM4); leukocyte migration (SCYA25); and B-cell proliferation and immunoglobulin secretion (LOC51293). Interestingly, one of these candidate gene, ACP5, belongs to a class of molecules, the acid phosphatases which have been shown to be involved in the production of hydroxyl free radicals known to have trypanocidal effects. (Texte intégral)

Bibliographic Details

Main Authors:	Kang'a, S., Nilsson, P., Goldammer, T., Mwakaya, J., Elliot, J.S., Womack, James E., Schwerin, M., Njagi, E.N.M., Hanotte, Olivier
Format:	conference_item biblioteca
Language:	eng
Published:	CIRAD
Subjects:	L10 - Génétique et amélioration des animaux, trypanosomose, bovin, résistance aux maladies, http://aims.fao.org/aos/agrovoc/c_7988, http://aims.fao.org/aos/agrovoc/c_1391, http://aims.fao.org/aos/agrovoc/c_2328,
Online Access:	http://agritrop.cirad.fr/512058/
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