Genetic polymorphism of microsatellite loci in MHC class II exon 2 gene and its association with endoparasitic infestation, predominantly Haemonchus contortus in Salem black goat.

MHC gene is highly polymorphic and plays central molecule in immune system in recognition of pathogens and parasites. The present study examined the variability of MHC class II DRB exon 2 gene using microsatellite analysis, and its association with Haemonchus contortus infestation in Salem Black goat population. Animals were naturally exposed to mixed infestation of endoparasites, predominantly Haemonchus contortus. Pooled fecal coproculture and larval identification showed predominant presence of haemonchus (L3) larva. Fecal egg count (FEC) and packed cell volume (PCV) were used as indicator traits. All the three studied loci, OarCP73, DYA, and ODRB1.2, were polymorphic having three, four, and four alleles and four, eight, and nine genotypes, respectively. The loci showed low to moderate values of polymorphic information content. The mean fecal egg count estimates were 477.12 ± 34.14 eggs per gram of feces and the mean PCV values were within the normal range; however, they showed negative correlation with FEC values. All the three microsatellite loci and the effect of genotypes on indicator traits were found to be statistically significant (p ≤ 0.05). The present study will be helpful in selection and breeding of goats for Haemonchosis resistance.

Udder and teat morphometry in relation to clinical mastitis in dairy cows.

The present study was undertaken to explore the association of occurrence of clinical mastitis with udder and teat morphometry in cattle. The relationship of nine udder and eight teat morphometric traits with the occurrence of clinical mastitis was analysed using a binomial logistic regression model. A significant association of the udder and teat morphometric traits with the occurrence of mastitis was observed both in Karan Fries and Sahiwal cattle. The rear udder height, rear udder width, udder width and fore udder attachment were found to be the important udder morphometric traits associated with the occurrence of mastitis. In both groups, mastitic animals had broader rear udder width, lower rear udder height and loose fore udder attachment with lengthy and thicker teats. The inclusion of udder and teat morphometric traits in the selection and breeding program of Karan Fries and Sahiwal cattle may help in selection of animals for mastitis resistance.

Resistance to ETEC F4/F18-mediated piglet diarrhoea: opening the gene black box.

Diarrhoea, a significant problem in pig rearing industry affecting pre- and post-weaning piglets is caused by enterotoxigenic Escherichia coli (ETEC). The ETEC are classified as per the fimbriae types which are responsible for bacterial attachment with enterocytes and release of toxins causing diarrhoea. However, genetic difference exists for susceptibility to ETEC infection in piglets. The different phenotypes found in pigs determine their (pigs') susceptibility or resistance towards fimbrial subtypes/variants (F4ab, F4ac, F4ad and F18). Specific receptors are present on intestinal epithelium for attachment of these fimbriae, which do not express to same level in all animals. This differential expression is genetically determined and thus their genetic causes (may be putative candidate gene or mutations) render some animals resistant or susceptible to one or more fimbrial subtypes. Genetic linkage studies have revealed the mapping location of the receptor loci for the two most frequent variants F4ab and F4ac to SSC13q41 (i.e. q arm of 13th chromosome of Sus scrofa). Some SNPs have been identified in mucin gene family, transferring receptor gene, fucosyltransferase 1 gene and swine leucocyte antigen locus that are proposed to be linked mutations for resistance/susceptibility towards ETEC diarrhoea. However, owing to the variety of fimbrial types and subtypes, it would be difficult to identify a single causative mutation and the candidate loci may involve more number of genes/regions. In this review, we focus on the genetic mutations in genes involved in imparting resistance/susceptibility to F4 or F18 ETEC diarrhoea and possibilities to use them as marker for selection against susceptible animals.

Exploring the molecular basis of resistance/ susceptibility to mixed natural infection of Haemonchus contortus in tropical Indian goat breed.

The present investigation was carried out with the objective to identify putative candidate genes / Quantitative trait loci for resistance / susceptibility towards Haemonchus infestation in tropical goat breed (Rohilkhandi goat) of India. The mean faecal egg count (FEC) and packed cell volume (PCV) of the population were 142.78 ± 22.54 epg (eggs per gram) and 31.73% ± 0.49, respectively. Grouping of animals as per dot ELISA test showed 41.33% (n = 124) positive and 58.66% (n = 176) negative for Haemonchus infestation. The microsatellite loci DYA and ODRB1.2 were significantly associated (P ≤ 0.05) to parasite resistance. The locus DYA showed significant association with log FEC and dot ELISA and the locus ODRB1.2 showed significant association with log FEC, PCV and dot ELISA at P ≤ 0.05. Real time expression profiling revealed that the susceptible group (high FEC group) had 11.1-fold more expression of IFNγ mRNA (Th1 cytokine) and 0.11-fold lower expression of IL-10 mRNA (Th2 cytokine), which was found to be statistically significant (P ≤ 0.05).

Genome wide occurrence and insertion preferences of INGI/RIME and SLACS CRE transposable elements in Trypanosoma brucei.

Retrotransposons play significant role in genome remodelling of T. brucei and about 5% of its genome consists of retrotransposons including INGI/RIME elements. INGI is one of the dispersed repetitive elements in T. brucei genome which is found distributed throughout all the chromosomes. SLACS (Spliced Leader Associated Conserved Sequence) however, is more conserved in its nature and lacks the typical poly-distributional pattern of LINE like transposons. We have found total 589 copies of these TEs with only 17.06 % (104 copies out of 589) copies with both ends intact thus showing a majority of truncated copies. Complete SLACS CRE were found only on chromosome 9, whereas, complete INGI/RIME were more ubiquitously distributed. The 50 - 70 bp upstream flanking sequence of these elements shows suitable nucleotide biophysical properties to favor transposition.

Dataset for distribution of INGI/RIME and SLACS CRE transposable elements in Trypanosoma brucei genome.

The current dataset is generated via bio-computational approach by surveying of INGI/RIME and SLACS CRE transposable elements (TEs) in latest update of Trypanosoma brucei genome. The distribution dataset (Supplementary File 1) shows the chromosome wise distribution of INGI/RIME and SLACS CRE transposable elements with the status of their -5' and -3' ends, genomic coverage and further elemental description about the completeness on the element. The 5' upstream flanking sequence of 100 bp was then analyzed to find out possible regions that could act as insertion hotspots. The Fig. 1 represents the ten different motifs found in the 5' flanking region of the INGI/RIME and SLACS CRE elements. The Supplementary File 2 describes the distribution of these ten motifs in different locations in Trypanosoma brucei genome. These new locations where motifs were found may provide useful information to track the future transposition events of INGI/RIME and SLACS CRE elements in different Trypanosoma species.

Genotyping of major histocompatibility complex Class II DRB gene in Rohilkhandi goats by polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing.

AIM: To study the major histocompatibility complex (MHC) Class II DRB1 gene polymorphism in Rohilkhandi goat using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing techniques. MATERIALS AND METHODS: DNA was isolated from 127 Rohilkhandi goats maintained at sheep and goat farm, Indian Veterinary Research Institute, Izatnagar, Bareilly. A 284 bp fragment of exon 2 of DRB1 gene was amplified and digested using BsaI and TaqI restriction enzymes. Population genetic parameters were calculated using Popgene v 1.32 and SAS 9.0. The genotypes were then sequenced using Sanger dideoxy chain termination method and were compared with related breeds/species using MEGA 6.0 and Megalign (DNASTAR) software. RESULTS: TaqI locus showed three and BsaI locus showed two genotypes. Both the loci were found to be in Hardy-Weinberg equilibrium (HWE), however, population genetic parameters suggest that heterozygosity is still maintained in the population at both loci. Percent diversity and divergence matrix, as well as phylogenetic analysis revealed that the MHC Class II DRB1 gene of Rohilkhandi goats was found to be in close cluster with Garole and Scottish blackface sheep breeds as compared to other goat breeds included in the sequence comparison. CONCLUSION: The PCR-RFLP patterns showed population to be in HWE and absence of one genotype at one locus (BsaI), both the loci showed excess of one or the other homozygote genotype, however, effective number of alleles showed that allelic diversity is present in the population. Sequence comparison of DRB1 gene of Rohilkhandi goat with other sheep and goat breed assigned Rohilkhandi goat in divergence with Jamanupari and Angora goats.

Single nucleotide polymorphism mining and nucleotide sequence analysis of Mx1 gene in exonic regions of Japanese quail.

AIM: An attempt has been made to study the Myxovirus resistant (Mx1) gene polymorphism in Japanese quail. MATERIALS AND METHODS: In the present, investigation four fragments viz. Fragment I of 185 bp (Exon 3 region), Fragment II of 148 bp (Exon 5 region), Fragment III of 161 bp (Exon 7 region), and Fragment IV of 176 bp (Exon 13 region) of Mx1 gene were amplified and screened for polymorphism by polymerase chain reaction-single-strand conformation polymorphism technique in 170 Japanese quail birds. RESULTS: Out of the four fragments, one fragment (Fragment II) was found to be polymorphic. Remaining three fragments (Fragment I, III, and IV) were found to be monomorphic which was confirmed by custom sequencing. Overall nucleotide sequence analysis of Mx1 gene of Japanese quail showed 100% homology with common quail and more than 80% homology with reported sequence of chicken breeds. CONCLUSION: The Mx1 gene is mostly conserved in Japanese quail. There is an urgent need of comprehensive analysis of other regions of Mx1 gene along with its possible association with the traits of economic importance in Japanese quail.