RESUMO
Two cases of hereditary bleeding disorder diagnosed as haemophilia A were recently observed in Japanese Brown cattle. We sequenced the entire coding region of the factor VIII gene of the affected animals to find a causative mutation. A nucleotide substitution of T to A resulting in an amino acid substitution of leucine to histidine (p.Leu2153His) was identified in a highly conserved residue in the C1 domain of factor VIII. Genotyping of 254 normal animals including the pedigree of the affected animals and randomly sampled animals of different breeds confirmed that the substitution is the causative mutation of cattle haemophilia A.
Assuntos
Doenças dos Bovinos/genética , Fator VIII/genética , Hemofilia A/veterinária , Mutação de Sentido Incorreto/genética , Animais , Sequência de Bases , Bovinos , Genótipo , Hemofilia A/genética , Japão , Dados de Sequência Molecular , Linhagem , Análise de Sequência de DNA/veterináriaRESUMO
A previous study had identified an African and an Asian race of the Old World screwworm fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), based on the 3' terminal 279 basepairs (bp) of the mitochondrial cytochrome b gene. The current study improved the phylogeographic resolution of cytochrome b for this species by characterizing more of the gene (the 3' terminal 715 bp) and by sampling more geographical populations, including Oman, Iran, Hong Kong and the Indonesian islands of Sulawesi and East Sumba. Strong support was found for recognizing an African race, but not for a monophyletic Asian race. The cladistic and genealogical relationships among the Asian populations were complex. There was sufficient genetic homogeneity throughout separate regions (mainland Asia and each Indonesian island) to suggest that there are no reproductive barriers within each region that might necessitate the production of more than one strain for control by the sterile insect technique (SIT). Primers were designed for the amplification by polymerase chain reaction of two nuclear loci, the highly conserved elongation factor-1alphagene and the less conserved white gene, and the preliminary results indicated that these genes showed the same pattern of small-scale regional variation as cytochrome b. The cytochrome b haplotypes are useful markers for identifying the geographical origins of any emerging infestations of the species: the absence of Indonesian and African haplotypes in the Middle East demonstrates that the large-scale transport of livestock is not spreading Old World screwworm.
Assuntos
Núcleo Celular/genética , Citocromos b/genética , Dípteros/genética , Mitocôndrias/genética , Animais , Pareamento de Bases , DNA/genética , DNA/isolamento & purificação , Primers do DNA , Dípteros/classificação , Amplificação de Genes , Geografia , FilogeniaRESUMO
Congenital multiple ocular defects (MOD) of Japanese black cattle is a hereditary ocular disorder with an autosomal recessive mode of inheritance showing developmental defects of the lens, retina and iris, persistent embryonic eye vascularization and microphthalmia. The MOD locus has been mapped by linkage analysis to a 6.6-cM interval on the proximal end of bovine chromosome 18, which corresponds to human chromosome 16q and mouse chromosome 8. To refine the MOD region in cattle, we constructed an integrated radiation hybrid (RH) map of the proximal region of bovine chromosome 18, which consisted of 17 genes and 10 microsatellite markers, using the SUNbRH7000 panel. Strong conservation of gene order was found among the corresponding chromosomal regions in cattle, human and mouse. The MOD-critical region was fine mapped to a 59.5-cR region that corresponds to a 6.3-Mb segment of human chromosome 16 and a 4.8-Mb segment of mouse chromosome 8. Several positional candidate genes, including FOXC2 and USP10, were identified in this region.
Assuntos
Doenças dos Bovinos/genética , Cromossomos de Mamíferos/genética , Oftalmopatias/veterinária , Genes/genética , Mapeamento de Híbridos Radioativos/veterinária , Animais , Bovinos , Primers do DNA , Oftalmopatias/genética , Ordem dos Genes/genética , Repetições de Microssatélites/genéticaRESUMO
PURPOSE: To investigate the role of scleral creep in the axial elongation of chick and tree shrew eyes with induced myopia. METHODS: Form-deprivation myopia was induced with a diffusing occluder worn over one eye. Scleral samples from the posterior pole and equatorial regions of myopic, contralateral (control), and age-matched normal chick and tree shrew eyes were loaded in vitro with a force of 5 g for 20 minutes while creep extension was monitored. The elastic behavior of sclera from myopic, control, and normal chick eyes was also compared. RESULTS: In both chick and tree shrew, posterior and equatorial scleral samples from myopic eyes had significantly (P < 0.05) greater creep extensions than equivalent samples from control and normal eyes (n = 10, each group). Among individual tree shrews the difference in creep rate between the sample from the myopic eye and that from the control eye correlated with vitreous chamber elongation (r = 0.746, P < 0.05) and development of myopia (r = 0.792, P < 0.01) in the deprived eye. No such association was found in the data from chicks. The elastic properties of chick sclera were unaffected in form-deprivation myopia. CONCLUSIONS: In chick and tree shrew, form-deprivation myopia is associated with increased creep rate of posterior and equatorial sclera. In tree shrew, the correlation between increased scleral creep rate and vitreous chamber elongation in myopic eyes supports the hypothesis that induced changes in the axial length of the mammalian eye are mediated by changes in the creep properties of the sclera.