Browsing by Author "Aymaz, Ramazan"
Now showing 1 - 5 of 5
- Results Per Page
- Sort Options
Publication A novel 2 bp deletion variant in ovine DRB1 gene is associated with increased visna/maedi susceptibility in Turkish sheep(Nature Portfolio, 2021-07-14) Yaman, Yalçın; Bay, Veysel; Aymaz, Ramazan; Keleş, Murat; Öner, Yasemin; Teferedegn, Eden Yıtna; Ün, Cemal; Öner, Yasemin; ÖNER, YASEMİN; Bursa Uludağ Üniversitesi/Ziraat Fakültesi.; JKO-1528-2023Visna/maedi (VM) is a multisystemic lentivirus infection of sheep that affecting sheep industry across the globe. TMEM154 gene has been identified to be a major VM-associated host gene, nevertheless, a recent study showed that the frequency of the VM-resistant TMEM154 haplotypes was very low or absent in indigenous sheep. Thus, the present study was designed to determine other possible co-receptors associated with VM. For this purpose, DRB1 gene, which is renowned for its role in host immune response against various diseases was targeted. A total number of 151 case-control matched pairs were constructed from 2266 serologically tested sheep. A broad range of DRB1 haplotype diversity was detected by sequence-based genotyping. Moreover, a novel 2 bp deletion (del) in the DRB1 intron 1 was identified. For the final statistic, the sheep carrying VM-resistant TMEM154 diplotypes were removed and a McNemar's test with a matched pairs experimental design was conducted. Consequently, it was identified for the first time that the 2 bp del variant is a genetic risk factor for VM (p value 0.002; chi-square 8.31; odds ratio 2.9; statistical power 0.90) in the dominant model. Thus, negative selection for 2 bp del variant could decrease VM infection risk in Turkish sheep.Publication Association between ovine toll-like receptor 4 (TLR4) gene coding variants and presence of eimeria spp. in naturally infected adult Turkish native sheep(Taylor, 2020-09-23) Yaman, Yalçın; Aymaz, Ramazan; Keles, Murat; Bay, Veysel; Özuiçli, Mehmet; Şenlik, Bayram; ÖZÜİÇLİ, MEHMET; ŞENLİK, BAYRAM; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Parazitoloji Anabilim Dalı; JIF-7199-2023; GBN-0139-2022Coccidiosis caused byEimeriaspp. is a protozoan disease prevalent in farm animals, and it is responsible for serious economic losses especially in young animals. It has been popular to breed disease-resistant animals due to the concern about food safety, animal welfare, and public health. Toll-like receptor (TLR) gene family plays a key role in the innate immune system participating in host-antigen interaction, therefore, they are candidate genes for breeding disease-resistant animals. In the present study, possible genetic associations betweenTLR4gene coding variants and the presence ofEimeriaspp. in adult Turkish sheep were investigated. For this purpose, the presence ofEimeriaspp. in fecal samples from six native Turkish sheep were determined, and approximately 1450 bp region in the 3rd exon of the ovineTLR4gene was sequenced. Ten nonsynonymous and four synonymous single nucleotide polymorphisms (SNPs) were detected in the targeted region. Statistical analyses revealed that the SNP at the codon at 356(th)position encoding Leucine instead of Phenylalanine (F356L) was significantly associated with the presence ofEimeriaspp. It was found that the individuals carrying at least one Leucine amino acid sequence at this position have 2.3-fold more risk for the presence ofEimeriaspp.Item Association of TMEM154 variants with visna/maedi virus infection in Turkish sheep(Elsevier, 2019-08) Yaman, Yalçın; Keleş, Murat; Aymaz, Ramazan; Sevim, Semih; Sezenler, Tamer; Önaldı, A. Taner; Kaptan, Cüneyt; Başkurt, Atilla; Koncagül, Seyrani; Özturk, Egemen Erdem; İriadam, Mehmet; Ün, Cemal; Heaton, Michael P.; Öner, Yasemin; Uludağ Üniversitesi/Ziraat Fakültesi/Zootekni, Biyometri ve Genetik Bölümü.; 0000-0002-2904-8986; ABB-3181-2020; 9634793800Visna/maedi (VM) is a multisystemic disease of sheep characterized by persistent lentiviral infection, slow progression and eventually death. The VM virus (VMV) affects sheep throughout the world and is the focus of national eradication campaigns. A major host gene associated with infection has been identified in North American sheep (TMEM154); however, its effect is unknown in Turkish sheep. Our aim was to determine VMV seroprevalence in naturally infected Turkish sheep, characterize their TMEM154 alleles, and test for association with infection. A 2017 serological census was taken of 2266 ewes from 11 flocks, at six locations, comprising seven native and four composite Turkish breeds. VMV serum antibodies were measured with an enzyme linked immunosorbent assay. Eight of 11 flocks were infected with VMV (2 to 83% seroprevalence). TMEM154 variants were typed by sequencing exon 2 from all 287 seropositive ewes and a subset of their seronegative flockmates (1059 total). TMEM154 sequencing revealed five of 12 known haplotypes encoding missense mutations, and one previously unreported variant (G38R) in Kivircik sheep. VMV seroprevalence in ewes with highly-susceptible TMEM154 haplotypes (full length E35 variants) was higher than the overall flock seroprevalence and independent of breed type. Genetic association was tested in 76 matched case-control pairs from 751 comingled ewes from a research flock. Pairwise analyses showed the risk of infection was 3-fold greater for ewes with one or two copies of highly-susceptible TMEMI54 haplotypes compared to those with combinations of K35 and deletion variants (CI95 1.3-8.7, p-value 0.009). Allelic combinations of TMEM154 K35 and deletion variants had an apparent protective effect against VMV strains in Turkish sheep. The low frequencies of K35 and deletion alleles in native Turkish breeds suggests selective breeding may help reduce the seroprevalence in affected flocks and decrease the risk of outbreaks in VMV-free flocks.Publication Detecting fecal egg count (FEC) for gastrointestinal nematodes of adult Turkish sheep with different scrapie related PRNP haplotypes(Taylor & Francis, 2020-12-10) Yaman, Yalçın; Şenlik, Bayram; Özuiçli, Mehmet; Keleş, Murat; Aymaz, Ramazan; Bay, Veysel; Hatipoğlu, Ecem; Koncagül, Seyrani; Öner, Yasemin; Ün, Cemal; ŞENLİK, BAYRAM; ÖZÜİÇLİ, MEHMET; ÖNER, YASEMİN; Bursa Uludağ Üniversitesi/Veteriner Fakültesi/Parazitoloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyometri ve Genetik Bölümü.; GBN-0139-2022 ; JIF-7199-2023 ; ABB-3181-2020Scrapie is a transmissible spongiform encephalopathy caused by prions and leads to neurodegeneration in the Central Nervous System (CNS) of sheep and goats. Genetic resistance/susceptibility to scrapie is well studied and it is known that the variations of 136th, 154th and 171st codons at the ovine PRNP gene have a major effect on the development of the disease. Many studies demonstrated that selection for PRNP genotypes has not influenced other performance traits, nevertheless, there is a knowledge gap about the possible link between the PRNP gene and the status of the other important diseases that affect the sheep population worldwide. In the present study, we tested whether there is an association between scrapie-related PRNP genotypes and fecal egg count (FEC) of gastrointestinal nematodes in seven adult Turkish sheep breeds. For this purpose, FEC scores of studied sheep (n = 253) were determined and the same animals were genotyped for the PRNP gene. Finally, an association analysis was performed for scrapie resistant (ARR), susceptible (VRQ), and wild-type (ARQ) haplotypes. Based on our statistical analysis, it is concluded that PRNP genotypes have no positive or negative effect on the FEC scores of adult sheep.Publication Documentation of extensive genetic diversity in the Ovar-DRB1 gene in native Turkish sheep(Taylor, 2021-02-02) Bay, Veysel; Keles, Murat; Aymaz, Ramazan; Hatipoğlu, Ecem; Öner, Yasemin; Yaman, Yalçın; ÖNER, YASEMİN; Bursa Uludağ Üniversitesi/Ziraat Fakültesi/Biyometri ve Genetik Bölümü; 0000-0002-2904-8986; ABB-3181-2020Indigenous breeds have a high level of genetic diversity that might contribute to develop animal breeds with desired traits such as disease resistance and high productivity. Major histocompatibility complex (MHC) is a key component of adaptive immune system and consists of highly polymorphic genes that take part in adaptive immune response and disease resistance. Exploring and understanding the effect of polymorphisms in MHC could be beneficial to future animal breeding strategies. In this study, we sequenced the highly polymorphic Exon2 of the ovine DRB1 gene using Sanger sequencing to explore the diversity of this gene in six indigenous Turkish sheep breeds and two crossbreeds. In total, 894 haplotypes from 447 sheep were investigated, and 69 different haplotypes including 27 novel ones were identified. Among the identified haplotypes there were common and breed specific haplotypes. There was a relatively high diversity of the alleles within indigenous breeds. Allelic diversity patterns were mostly associated with geographical differences. The results of this study highlight the genetic variation within indigenous breeds which has important implications for biodiversity and the adaptability of breeds to specific environments. There is value to further studies which include other genomic regions and traits, and these could guide breeding strategies.