Lack of specific alleles for the bovine chemokine (C-X-C) receptor type 4 (CXCR4) gene in West African cattle questions its role as a candidate for trypanotolerance.
A panel of 81 Asian, African and European cattle (Bos taurus and B. indicus) was analysed for the whole sequence of the CXCR4 gene (3844bp), a strong candidate for cattle trypanotolerance. Thirty-one polymorphic sites identified gave 31 different haplotypes. Neutrality tests rejected the hypothesis of either positive or purifying selection. Bayesian phylogenetic tree showed differentiation of haplotypes into two clades gathering genetic variability predating domestication. Related with clades definition, linkage disequilibrium analyses suggested the existence of one only linkage block on the CXCR4 gene. Two tag SNPs identified on exon 2 captured 50% of variability. Whatever the analysis carried out, no clear separation between cattle groups was identified. Most haplotypes identified in West African taurine cattle were also found in European cattle and in Asian and West African zebu. West African taurine samples did not carry unique variants on the CXCR4 gene sequence. The current analysis failed in identifying a causal mutation on the CXCR4 gene underlying a previously reported QTL for cattle trypanotolerance on BTA2.
Área de Genética y Reproducción Animal, SERIDA, Camino de los Claveles 604, 33203 Gijón, Spain.
Isabel
I
Álvarez
CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal.
Lucía
L
Pérez-Pardal
INERA, 04 BP 8645 Ouagadougou 04, Burkina Faso.
Amadou
A
Traoré
Área de Genética y Reproducción Animal, SERIDA, Camino de los Claveles 604, 33203 Gijón, Spain.
Iván
I
Fernández
Área de Genética y Reproducción Animal, SERIDA, Camino de los Claveles 604, 33203 Gijón, Spain. Electronic address: fgoyache@serida.org.
Félix
F
Goyache
D000354:Africa, Western / Q000453:epidemiology; D000483:Alleles; D000818:Animals; D001499:Bayes Theorem; D002417:Cattle; D033481:Chromosomes, Mammalian / Q000737:chemistry; D005091:Exons; D015870:Gene Expression; D006239:Haplotypes; D007108:Immune Tolerance; D015810:Linkage Disequilibrium; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D019718:Receptors, CXCR4 / Q000145:classification / Q000235:genetics* / Q000276:immunology; D014345:Trypanosoma / Q000502:physiology; D014354:Trypanosomiasis, Bovine / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology / Q000469:parasitology
D019718:Receptors, CXCR4
Bos indicus; Bos taurus; CXCR4; Trypanotolerance; West Africa