In our previous studies, microRNA-432 (miR-432) was found to be one of differentially expressed miRNAs in ovine mammary gland between the two breeds of lactating sheep with different milk production...

Southern hybridization analysis of the ovine major histocompatibility complex (MHC) (MhcOvar) class I1 region, using sheep-specific probes for the DQAl, DQA2, DQB and DRA loci, has revealed extensive polymorphism. DQAl and DQAP had eight and 16 alleles respectively, DQB had six and DRA had three alleles. Little information was derived from the DRB locus owing to extensive cross-hybridization between the DRB probe and the DQB locus. Differences in allele frequency between breeds were revealed. At the DQAl locus a null allele (DQAl-N) was observed with a frequency of between 27% and 45%, making this the most common DQAl allele in all breeds examined. The frequency of DQA1-N homozygotes was between 11% and 18%, raising questions as to the functional significance of the DQAl gene. Linkage analysis between the D Q A l , DQAZ, DQB and DRA loci did not reveal any recombination.

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________________________________________________________________________________ AbstractThis study aimed at identifying gene markers associated with wool quality traits in Merino and Merino Cross sheep using a candidate gene approach. Polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis was used to identify sequence variation in the KAP1.3 and K33 genes, while agarose gel electrophoresis was used to detect length variation in the KAP1.1 gene. Two half-sib families (SL1 and SL2) were created for analysis and wool samples were collected from the mid-side region of the SL1 progeny at 12, 24 and 36 months of age, and of the SL2 progeny at 12 months of age. The association of alleles was analysed for each year of phenotypic data by an analysis of variance (ANOVA) tests, using SPSS® version 15. Analysis of each of KAP1.1, KAP1.3 and K33 genes revealed potential gene markers to select for animals with increased staple length, increased staple strength, higher yield, whiter and brighter wool. The results obtained are consistent with KAP1.1, KAP1.3 and KRT1.2 being clustered on one chromosome. Results also indicated that the keratin genes on chromosome 11 are recombining relatively frequently at recombination "hotspots". It appears as though genes coding for the KRTs and KAPs have the potential to impact on wool quality and could potentially be exploited in gene marker-assisted selection programmes in the wool industry for the rapid conversion of wool from one type to another ________________________________________________________________________________

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Animal production is a booming industry with the improvement of economically desirable traits as its primary concern. Markerassisted selection utilizes genetic variations within candidate genes that influence production traits as a means of guiding animal breeding and improving the traits of interest. Growth hormone (GH) plays a crucial role in pre-natal muscular and bone growth and development. GH brings about various physiological functions either directly by binding its receptor or indirectly by stimulating the release of insulin growth factor 1 (IGF1). Insulin growth factor 1 receptor (IGF1R) mediates its function on metabolism, homeostasis and development upon the binding of IGF1. The POU-domain class 1 transcription factor 1 (POU1F1) regulates the pre-natal development of cells of the anterior pituitary, including somatotrophs that produce GH. Reports have demonstrated associations between polymorphisms in these genes and animal production traits. This novel study examined the polymorphisms in the coding regions of candidate genes, GH2Z, IGF1R and POU1F1, in New Zealand (NZ) sheep. The sheep breeds investigated were NZ Romney and Merino, two commercially sought-after breeds. The results revealed two variants, AA and AB, for the exon 3 of POU1F1. The AA and AB genotypes had frequencies of 78% and 22% for Romney sheep, and 64% and 36% for Merino sheep respectively. All frequencies were in accordance with the Hardy-Weinberg Equilibrium (P > 0.05). The exon 2 of GH2Z revealed multiple variations while no variation was detected for the exon 15 of IGF1R..

DNA repeats are common elements in eukaryotic genomes, and their multi-copy nature provides the opportunity for genetic exchange. This exchange can produce altered evolutionary patterns, including concerted evolution where within genome repeat copies are more similar to each other than to orthologous repeats in related species. Here we investigated the genetic architecture of the keratin-associated protein (KAP) gene family, KRTAP1. This family encodes proteins that are important components of hair and wool in mammals, and the genes are present in tandem copies. Comparison of KRTAP1 gene repeats from species across the mammalian phylogeny shows strongly contrasting evolutionary patterns between the coding regions, which have a concerted evolution pattern, and the flanking regions, which have a normal, radiating pattern of evolution. This dichotomy in evolutionary pattern transitions abruptly at the start and stop codons, and we show it is not the result of purifying selection acting to maintain species-specific protein sequences, nor of codon adaptation or reverse transcription of KRTAP1-n mRNA. Instead, the results are consistent with short-tract gene conversion events coupled with selection for these events in the coding region driving the contrasting evolutionary patterns found in the KRTAP1 repeats. Our work shows the power that repeat recombination has to complement selection and finely tune the sequences of repetitive genes. Interplay between selection and recombination may be a more common mechanism than currently appreciated for achieving specific adaptive outcomes in the many eukaryotic multi-gene families, and our work argues for greater emphasis on exploring the sequence structures of these families.