A search for genes affecting Trichostrongylus colubriformis resistance in sheep

Beh, K.J.; Callaghan, M.J.; Hulme, D.J.; Leish, Z.; Dilenno, K

doi:10.1016/s1383-5769(98)80249-3

Cited by 6 publications

(7 citation statements)

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“…These include the localization of the chromosomal regions containing the genes for Booroola fecundity, callipyge, and Horns on chromosomes 6, 18, and 10, respectively (Montgomery et al 1993(Montgomery et al , 1994(Montgomery et al , 1996Cockett et al 1994) and the identification of the fibroblast growth factor receptor 3 (FGFR3) gene as the causative gene for Spider Lamb Syndrome ) and the bone morphogenetic (Galloway et al 2000). Recently, data have also been presented for the localization of a number of QTLs, including ones for wool quality (Robinson et al 1997), parasite resistance (Beh et al 1998;Crawford 1998), facial eczema (Phua et al 1998), and dagginess (MacDonald et al 1998). …”

Section: Discussionmentioning

confidence: 99%

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

Maddox¹

2001

Genome Research

211

136

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A medium-density linkage map of the ovine genome has been developed. Marker data for 550 new loci were generated and merged with the previous sheep linkage map. The new map comprises 1093 markers representing 1062 unique loci (941 anonymous loci, 121 genes) and spans 3500 cM (sex-averaged) for the autosomes and 132 cM (female) on the X chromosome. There is an average spacing of 3.4 cM between autosomal loci and 8.3 cM between highly polymorphic [polymorphic information content (PIC) Ն 0.7] autosomal loci. The largest gap between markers is 32.5 cM, and the number of gaps of >20 cM between loci, or regions where loci are missing from chromosome ends, has been reduced from 40 in the previous map to 6. Five hundred and seventy-three of the loci can be ordered on a framework map with odds of >1000 : 1. The sheep linkage map contains strong links to both the cattle and goat maps. Five hundred and seventy-two of the loci positioned on the sheep linkage map have also been mapped by linkage analysis in cattle, and 209 of the loci mapped on the sheep linkage map have also been placed on the goat linkage map. Inspection of ruminant linkage maps indicates that the genomic coverage by the current sheep linkage map is comparable to that of the available cattle maps. The sheep map provides a valuable resource to the international sheep, cattle, and goat gene mapping community.Sheep play an important role in modern agriculture and possess many heritable traits that are of economic importance. Additionally, the size, physiology, temperament, and lifespan of sheep make them an appropriate model for studying a variety of mammalian biological functions including lung physiology, immunology, endocrinology, reproduction, embryology, and fetal development. Sheep are also useful as disease models for inherited diseases, such as asthma (Wright et al.

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Section: Discussionmentioning

confidence: 99%

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

Maddox¹

2001

Genome Research

211

136

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“…A genomewide scan was conducted by genotyping animals in the pedigrees with microsatellite markers and testing for linkage between the markers and FEC. Quantitative trait loci associated with T. colubriformis resistance were reported on chromosomes 1, 3, 6, 22, and 23, and QTL associated with resistance to H. contortus were identified on chromosomes 1, 3, 6, 14, and 23 (Beh et al, 1998). AgResearch (New Zealand) has established a selection line of Romney sheep for resistance to natural field challenge measured by FEC (Crawford et al, 1997).…”

Section: Marker-assisted Selectionmentioning

confidence: 99%

Immunological aspects of nematode parasite control in sheep1

Miller

Horohov

2006

Journal of Animal Science

137

102

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Gastrointestinal nematode parasitism is arguably the most serious constraint affecting sheep production worldwide. Economic losses are caused by decreased production, the costs of prophylaxis and treatment, and the death of the infected animals. The nematode of particular concern is Haemonchus contortus, which can cause severe blood loss resulting in anemia, anorexia, depression, loss of condition, and eventual death. The control of nematode parasites traditionally relies on anthelmintic treatment. The evolution of anthelmintic resistance in nematode populations threatens the success of drug treatment programs. Alternative strategies for control of nematode infections are being developed, and one approach is to take advantage of the host's natural or acquired immune responses, which can be used in selection programs to increase the level of resistance in the population. Vaccination can also be used to stimulate or boost the host's acquired immunity. The induction of protective resistance is dependent on the pattern of cytokine gene expression induced during infection by two defined CD4+ T-helper cell subsets, which have been designated as Th1 or Th2. Intracellular parasites most often invoke a Th1-type response, and helminth parasites a Th2-type response. Breeds of sheep resistant to infection have developed resistance over a much longer term of host-parasite relationship than genetically selected resistant lines. The immune components involved in these different responses and types of host-parasite relationships will be reviewed. The potential for using vaccines has been investigated, with variable results, for several decades. The few successes and potential new antigen candidates will also be reviewed.

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“…Preliminary reports of the identification of sheep quantitative trait loci (QTLs) include parasite resistance (4,20), wool production traits (47,73), milk traits (27), and fecal soiling of the wool or dagginess (56). Development of additional resource flocks is ongoing for traits in sheep such as parasite resistance, out-of-season breeding, carcass traits, and wool production.…”

Section: Identification Of Qtls For Wool Meat and Milk In Sheepmentioning

confidence: 99%

“…Resource families suitable for the identification of genetic markers for resistance to Trichostrongylus colubriformis have been established by Commonwealth Scientific and Industrial Research Organisation (CSIRO, Australia), AgResearch (New Zealand), and the University of Melbourne and for Haemonchus contortus by Louisiana State University, CSIRO, and International Livestock Research Institute (ILRI, Kenya). The initiation of whole genome scans has been reported by CSIRO (4) and AgResearch (20), but information on specific chromosomal regions that contain QTLs for parasite resistance are not yet available.…”

Section: Identification Of Qtls For Wool Meat and Milk In Sheepmentioning

confidence: 99%

Analysis of the sheep genome

Cockett

Shay

Smit

2001

Physiological Genomics

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The identification of genes controlling several traits of interest in sheep has been accomplished by positional candidate cloning. In these studies, the trait is first mapped to a specific chromosomal region by linkage analysis, which requires families that are segregating for the trait and for polymorphic markers. Microsatellite markers are usually used for these analyses because of their extensive genetic variability. Once the location of a trait is determined by linkage to the markers, possible candidate genes controlling the trait can be inferred because of their proximity to linked markers. It is not necessary to map all possible genes in sheep for this strategy to be effective. Rather, a subset of genes that are mapped in humans and mice have also been mapped in sheep; these genes serve as "anchors" across the comparative maps of the different species. Further study of these positional candidates has revealed naturally occurring mutations that produce phenotypes that are unique to sheep. Thus the genetic analysis of sheep traits advances knowledge not only in this species but provides critical information for understanding biological pathways in mammalian species.

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A search for genes affecting Trichostrongylus colubriformis resistance in sheep

Cited by 6 publications

References 0 publications

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

Immunological aspects of nematode parasite control in sheep1

Analysis of the sheep genome

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