Ovine keratome: identification, localisation and genomic organisation of keratin and keratin-associated proteins.

Wool is composed primarily of proteins belonging to the keratin family. These include the keratins and keratin-associated proteins (KAPs) that are responsible for the structural and mechanical properties of wool fibre. Although all human keratin and KAP genes have been annotated, many of their ovine counterparts remain unknown and even less is known about their genomic organisation. The aim of this study was to use a combinatory approach including comprehensive cDNA and de novo genomic sequencing to identify ovine keratin and KAP genes and their genomic organisation and to validate the keratins and KAPs involved in wool production using ovine expressed sequence tag (EST) libraries and proteomics. The number of genes and their genomic organisation are generally conserved between sheep, cattle and human, despite some unique features in the sheep. Validation by protein mass spectrometry identified multiple keratins (types I and II), epithelial keratins and KAPs. However, 15 EST-derived genes, including one type II keratin and 14 KAPs, were identified in the sheep genome that were not present in the NCBI gene set, providing a significant increase in the number of keratin genes mapped on the sheep genome.

Molecular and functional characterization of the cystic fibrosis transmembrane conductance regulator from the Australian common brushtail possum, Trichosurus vulpecula.

Unlike eutherian mammals, the colon of the Australian common brushtail possum, Trichosurus vulpecula, a metatherian mammal, is incapable of electrogenic Cl(-) secretion and has elevated levels of electrogenic Na(+) absorption, while the ileum secretes HCO (3) (-) rather than Cl(-). In eutherian mammals, the cystic fibrosis transmembrane conductance regulator (CFTR) is essential for both Cl(-) and HCO (3) (-) secretion and the regulation of Na(+) absorption. Therefore, we have sequenced possum (p)CFTR, described its distribution and characterized the properties of cloned pCFTR expressed in Fischer rat thyroid (FRT) cells. pCFTR (GenBank accession No. AY916796) has a 1,478 amino acid open reading frame, which has >90% identity with CFTR from other marsupials and >80% identity with non-rodent eutherian mammals. In pCFTR, there is a high level of conservation of the transmembrane and nucleotide binding domains although, with the exception of other marsupials, there is considerable divergence from other species in the R domain. FRT cells transfected with pCFTR express mature CFTR protein which functions as a small Cl(-) channel activated by cAMP-dependent phosphorylation. In whole-cell recordings it has a linear, time and voltage-independent conductance, with a selectivity sequence P(Br) > P(Cl) > P(I) > P(HCO)(3) >> P(Gluconate). pCFTR transcript is present in a range of epithelia, including the ileum and the colon. The presence of pCFTR in the ileum and its measured HCO (3) (-) permeability suggest that it may be involved in ileal HCO (3) (-) secretion. Why the possum colon does not secrete Cl(-) and has elevated electrogenic Na(+) absorption, despite the apparent expression of CFTR, remains to be determined.

Generation of a preliminary bovine gene atlas, using expression clustering to annotate gene function.

Genes whose products function in a common biological process are often co-regulated. When regulation occurs at the transcriptional level, co-expressed genes can be detected globally by expression arrays or by sequencing non-normalized cDNA libraries. We examined bovine gene expression in 27 tissues using non-normalized cDNA library sequencing. Contigs were generated from expressed sequence tags whose sequences overlapped. Contigs containing a minimum of five expressed sequence tags were ordered via a hierarchical clustering process, where the distance between the contigs represents their expression pattern similarity across tissues. Gene ontology terms associated with the genes in each cluster showed that co-clustered genes encoded proteins involved in a common biological process. This process can be used to annotate genes of unknown function in the cluster. Gene expression was compared between bovine and human tissues; there were significant correlations between species for each tissue, with the exception of thyroid and placenta. Tissues were also clustered based on the genes they express; tissues with similar physiological functions clustered closely. Based on this information, we generated the first preliminary gene atlas of the bovine genome. Genes with similar expression patterns were clustered, and genes with a common function co-clustered. This method can be used to annotate genes of unknown function in the bovine genome.

A QTL study of growth and body shape in the inter-species hybrid of Père David's deer (Elaphurus davidianus) and red deer (Cervus elaphus).

An interspecies deer hybrid resource population developed from a cross of Père David's and red deer was used to detect QTL that account for species differences. A genome scan, coupled with composite interval mapping, was conducted to search for QTL controlling body measurements at pre-pubescent age (6 months of age) and puberty (15 months of age) in this interspecies hybrid. Five linkage groups that harbour QTL affecting morphology were identified. A joint-traits analysis was used to search for putative pleiotropic QTL on four of these linkage groups, and three were significantly associated with pleiotropic QTL for nose width and foot length (metacarpal and phalanges), which collectively accounted for 29-58% of the phenotypic difference between the two deer species. This study suggests that a few loci with large pleiotropic effects may be responsible for species-specific differences in growth and structure-related traits.

Inheritance of resistance to facial eczema: a review of research findings from sheep and cattle in New Zealand.

Facial eczema (FE) is a costly problem to New Zealand pastoral agriculture, and has a detrimental impact on animal wellbeing. Incidence and severity of the disease can be reduced by grazing management and zinc prophylaxis. An additional strategy is to breed animals that are genetically resistant to intoxication with sporidesmin, the causative mycotoxin. This review summarises research findings on the inheritance of resistance of animals to FE, including evidence of among- and within-breed genetic variation, direct and correlated responses to selection, and identification of genetic markers and candidate genes for FE resistance.