ABSTRACT
AIM: To use an established high through-put genotyping procedure to gain an estimate of the frequency of alleles of the prion protein (PrP) gene in some common sheep breeds in New Zealand. METHODS: Using a genotyping procedure based on matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF), DNA samples from 3,024 sheep from New Zealand, including breeds such as Romney, Texel, Coopworth, Merino and mixed breed, were isolated, genotyped and the results analysed. RESULTS: The 15 scrapie genotypes commonly reported, and derived from the five commonly reported allelic variants (ARR, ARQ, AHQ, ARH and VRQ), were all observed in the samples analysed. The estimates were indicative of the frequencies in the population of alleles present in breeds of sheep in New Zealand. There was a significant difference between the frequencies of alleles between breeds, but the ARQ, followed by the ARR allele, were, except in Carwell sheep, the most common alleles present. CONCLUSION: This study gave an indication of the percentages of PrP gene alleles in sheep in New Zealand, including data previously unreported from breeds in this country. It is of interest because of the relatively large size of the sheep population in New Zealand compared with many countries, and it provides some useful information on the genetic susceptibility or resistance of the sheep population in New Zealand to scrapie. The frequencies of the alleles can be different for an individual breed compared between countries.
Subject(s)
PrPSc Proteins/isolation & purification , Scrapie/epidemiology , Scrapie/microbiology , Animals , DNA/analysis , DNA Primers , Female , Genotype , New Zealand/epidemiology , Pedigree , Polymerase Chain Reaction/veterinary , PrPSc Proteins/genetics , Scrapie/etiology , SheepABSTRACT
Geneticists have been interested in inbreeding and inbreeding depression since the time of Darwin. Two alternative approaches that can be used to measure how inbred an individual is involve the use of pedigree records to estimate inbreeding coefficients or molecular markers to measure multilocus heterozygosity. However, the relationship between inbreeding coefficient and heterozygosity has only rarely been investigated. In this paper, a framework to predict the relationship between the two variables is presented. In addition, microsatellite genotypes at 138 loci spanning all 26 autosomes of the sheep genome were used to investigate the relationship between inbreeding coefficient and multilocus heterozygosity. Multilocus heterozygosity was only weakly correlated with inbreeding coefficient, and heterozygosity was not positively correlated between markers more often than expected by chance. Inbreeding coefficient, but not multilocus heterozygosity, detected evidence of inbreeding depression for morphological traits. The relevance of these findings to the causes of heterozygosity--fitness correlations is discussed and predictions for other wild and captive populations are presented.
Subject(s)
Heterozygote , Inbreeding , Models, Genetic , Sheep, Domestic/genetics , Animals , Microsatellite Repeats/geneticsABSTRACT
Bone density (BD) is an important factor in osteoporotic fracture risk in humans. However, BD is a complex trait confounded by environmental influences and polygenic inheritance. Sheep provide a potentially useful model for studying differences in BD, as they provide a means of circumventing complex environmental factors and are a similar weight to humans. The aims of this study were to establish whether there is genetic variation in BD in sheep and then to localise quantitative trait loci (QTLs) associated with this variation. We also aimed to evaluate the relationship between fat and muscle body components and BD in sheep. Results showed that there was significant (P < 0.01) genetic variation among Coopworth sheep sires for BD. This genetic difference was correlated (P < 0.01) with body weight and muscle mass. A number of QTLs exceeding the suggestive threshold were identified (nine in total). Of these, two (chromosomes 1, P < 0.05; chromosome 24, P < 0.01) were significant using genome-wide permutation significance thresholds (2000 iterations). The position of the QTL on chromosome 24 coincided with a number of other body composition QTLs, indicating possible pleiotropic effects or the presence of multiple genes affecting body composition at that site. This study shows that sheep are potentially a useful model for studying the genetics of BD.
Subject(s)
Bone Density/genetics , Sheep/genetics , Sheep/metabolism , Animals , Female , Fractures, Bone/etiology , Genetic Variation , Humans , Male , Models, Animal , Osteoporosis/complications , Osteoporosis/genetics , Osteoporosis/metabolism , Phenotype , Quantitative Trait Loci , Species SpecificitySubject(s)
Chromosome Mapping/veterinary , Microsatellite Repeats/genetics , Receptors, Bradykinin/genetics , Retroviridae Proteins, Oncogenic/genetics , Sheep/genetics , Animals , Chromosomes, Artificial, Bacterial , DNA/genetics , Electrophoresis, Polyacrylamide Gel/veterinary , Mice , Oncogene Protein v-akt , Polymerase Chain Reaction/veterinary , Polymorphism, Genetic/genetics , Receptor, Bradykinin B2ABSTRACT
The CNS may be instrumental in assisting patients, families, and staff in dealing effectively with loss and grief. This paper presents a review of theoretical and research literature examining theories and current research on grief. Physical and emotional responses to loss are discussed, and factors that influence the bereavement process are presented. The role of the CNS in facilitating grief resolution and in assisting the staff nurse to intervene appropriately with the bereaved is examined.
