Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first...Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first time the genetic variation within a candidate‘grazing gene',the glutamate metabotropic receptor 5 gene(GRM5),and tested associations between variation in that gene and variation in grazing personality behaviours(GP-behaviours)displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand.Mature beef cows(n=303,from 3 to 10 years of age)were tracked with global positioning system(GPS)and,with 5-minutes(min)relocation frequency,various GP-behaviours were calculated.These included horizontal and vertical distances travelled,mean elevation,elevation range,elevation gain,slope,home range and movement tortuosity,variously calculated using daily relocation trajectories with repeated measurements(i.e.,7 to 24 days(d))and satellite-derived digital elevation models(DEM).The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.Results:We discovered three GRM5 variants(A,B and C)and identified the six possible genotypes in the cattle studied.The mixed models revealed that A was significantly associated with elevation range,home range and movement tortuosity.Similarly,GRM5 genotypes were associated(P<0.05)to home range and movement tortuosity,while trends suggesting association(P<0.1)were also revealed for elevation range and horizontal distance travelled.Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor.The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age.Home range and movement tortuosity were not only associated with GRM5 variation,but also negatively correlated with each other(r=-0.27,P<0.001).Conclusions:There seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.展开更多
Keratin-associated proteins (KAPs) are a major structural component of hair and wool fibres, and play a critical role in determining the properties of the fibre. To date, forty functional high sulphur KAP genes from f...Keratin-associated proteins (KAPs) are a major structural component of hair and wool fibres, and play a critical role in determining the properties of the fibre. To date, forty functional high sulphur KAP genes from fourteen families have been identified in humans, but only six functional high sulphur KAP genes have been identified in sheep. This led us to search for the ovine KAP13-3 gene, a gene encoding a high sulphur KAP. In this study, the notional KAP13- 3 gene (KRTAP13-3) was amplified using primers designed based on a reported bovine KRTAP13-3 se- quence. PCR-single stranded conformational polymorphism (PCR-SSCP) analysis was used to screen amplicons derived from the gene in one hundred and forty seven New Zealand Romney crossbred sheep. Five unique banding patterns were revealed. Either one PCR-SSCP pattern (homozygous) or a combination of two patterns (heterozygous) was observed for each sheep. Sequencing of PCR amplicons representtative of different SSCP patterns revealed five different DNA sequences. The sequences derived from the amplicons showed a low homology to other known ovine KRTAPs, but had a high homology with previous reported KRTAP13-n sequences from human and cattle, with the closest homology being with bovine KRTAP13-3, suggesting the sequences represent the ovine KRTAP13-3 locus. Among the five allele sequences, four nucleotide substitutions were identified within the coding region. Of these substitutions, three were non-synonymous and would result in amino acid changes (p.Arg79Cys, p.Arg81Gln and p.Tyr130His). This variation in the KAP13-3 gene may affect gene expression, the structure and assembly of the protein, and consequently influence wool traits, if KAP13-3 is of importance to wool fibre structure.展开更多
基金CAMG was funded with a Lincoln University Ph D scholarship(Lincoln University Centennial Trust,New Zealand)with research funding from the New Zealand Hereford Association(NZHA)the Hellaby Grasslands Trust。
文摘Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first time the genetic variation within a candidate‘grazing gene',the glutamate metabotropic receptor 5 gene(GRM5),and tested associations between variation in that gene and variation in grazing personality behaviours(GP-behaviours)displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand.Mature beef cows(n=303,from 3 to 10 years of age)were tracked with global positioning system(GPS)and,with 5-minutes(min)relocation frequency,various GP-behaviours were calculated.These included horizontal and vertical distances travelled,mean elevation,elevation range,elevation gain,slope,home range and movement tortuosity,variously calculated using daily relocation trajectories with repeated measurements(i.e.,7 to 24 days(d))and satellite-derived digital elevation models(DEM).The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.Results:We discovered three GRM5 variants(A,B and C)and identified the six possible genotypes in the cattle studied.The mixed models revealed that A was significantly associated with elevation range,home range and movement tortuosity.Similarly,GRM5 genotypes were associated(P<0.05)to home range and movement tortuosity,while trends suggesting association(P<0.1)were also revealed for elevation range and horizontal distance travelled.Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor.The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age.Home range and movement tortuosity were not only associated with GRM5 variation,but also negatively correlated with each other(r=-0.27,P<0.001).Conclusions:There seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.
文摘Keratin-associated proteins (KAPs) are a major structural component of hair and wool fibres, and play a critical role in determining the properties of the fibre. To date, forty functional high sulphur KAP genes from fourteen families have been identified in humans, but only six functional high sulphur KAP genes have been identified in sheep. This led us to search for the ovine KAP13-3 gene, a gene encoding a high sulphur KAP. In this study, the notional KAP13- 3 gene (KRTAP13-3) was amplified using primers designed based on a reported bovine KRTAP13-3 se- quence. PCR-single stranded conformational polymorphism (PCR-SSCP) analysis was used to screen amplicons derived from the gene in one hundred and forty seven New Zealand Romney crossbred sheep. Five unique banding patterns were revealed. Either one PCR-SSCP pattern (homozygous) or a combination of two patterns (heterozygous) was observed for each sheep. Sequencing of PCR amplicons representtative of different SSCP patterns revealed five different DNA sequences. The sequences derived from the amplicons showed a low homology to other known ovine KRTAPs, but had a high homology with previous reported KRTAP13-n sequences from human and cattle, with the closest homology being with bovine KRTAP13-3, suggesting the sequences represent the ovine KRTAP13-3 locus. Among the five allele sequences, four nucleotide substitutions were identified within the coding region. Of these substitutions, three were non-synonymous and would result in amino acid changes (p.Arg79Cys, p.Arg81Gln and p.Tyr130His). This variation in the KAP13-3 gene may affect gene expression, the structure and assembly of the protein, and consequently influence wool traits, if KAP13-3 is of importance to wool fibre structure.