Thumbnail Image

Theses

Browse

20104
Reset filters
Subject: Animal Genetics and Breeding × End date: 2015 × Start date: 2010 × Type: Thesis ×
Reset filters

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    ThesisItemOpen Access
    Genetic polymorphism of major histocompatibility complex class II genes
    (Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 2010) Remya John, v; KAU; Raghavan, K C
  • Thumbnail Image
    ThesisItemOpen Access
    Beta lactoglobulin polymorphism in goats of Kerala
    (Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 2010) Sudina, K; KAU; Bindu, K.A
    Βeta-lactoglobulin gene polymorphism and its association with various milk production traits were investigated in DNA samples isolated from blood of 20 Malabari, 25 Attappady black 30 crossbred goats of University goat farm and 45 Malabari goats from the native tract of Malabari breed. Study was conducted by PCR-RFLP using Sac II restriction endonuclease. Digestion of the amplified PCR product with Sac II restriction endonuclease revealed three genotypes (S1S1, S1S2 and S2S2) in Malabari, Attappady black and crossbred goats, indicating the presence of S1 (349 and 77 bp fragments) and S2 (426 bp fragment) alleles. The S1/S2 allele frequencies were 0.37/0.63, 0.34/0.66 and 0.18/0.82, respectively in Malabari, Attappady black and crossbred goats. The genotypes of β-LG/Sac II polymorphism were distributed according to Hardy-Weinberg equilibrium with frequencies 0.04 (S1S1), 0.60 (S1S2) and 0.36 (S2S2) in Attappady black and 0.10 (S1S1), 0.17 (S1S2) and 0.73 (S2S2) in crossbred goats under study. But the Malabari goat population under study with genotype frequencies 0.14 (S1S1), 0.46 (S1S2) and 0.40 (S2S2), was found to violate H-W equilibrium. So this population was further classified and genotypic frequencies of subpopulations like Tellicherry (0.14, 0.50, 0.36), Badagara (0.2, 0.25, 0.55) and University farm (0.09, 0.61, 0.30) populations were in Hardy-Weinberg equilibrium. From the present study a significant association could be detected between β-LG polymorphism and peak milk yield in Malabari breed but not in other groups. Malabari goats carrying S2 allele showed a significantly higher average (p<0.05) (420±74.24 ml and 501.79±46.47 ml) compared to animals homozygous for S1 allele (250±13.36 ml). A statistically significant association could not be established between β-LG polymorphism and other milk production traits. So the introduction of this polymorphism can complement current selection programme.
  • Thumbnail Image
    ThesisItemOpen Access
    Evaluation and comparison of polymorphism of beta casein gene in vechur and crossbred cattle of Kerala
    (Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 2010) Muhammed, E M; KAU; Stephen Mathew
    Beta casein (β-CN) is the major milk protein which imparts biological, technological and physical properties to the milk. Recently, the polymorphism of the gene at codon 67 has attracted much public health attention. A single nucleotide polymorphism (SNP) from CCT to CAT leads to an amino acid change in the mature protein from proline to histidine. Among the twelve β-CN variants identified A1 and A2 are the common types and others are very rare. A1 variant has histidine at position 67 of the amino acid sequence while A2 possess proline at this position. This single amino acid change causes the release of bioactive peptides upon gastro intestinal digestion. Morphine like opioid beta casomorphine-7 (BCM-7) thus released from A1 milk is reported to cause various illness like diabetes mellitus, heart diseases, atherosclerosis, schizophrenia and sudden infant death syndrome (SIDS). The original variant A2 does not produce BCM-7 and thus is safe for human consumption. The major taurine milch breeds such as Holstein Friesian and Ayrshire have a high frequency of A1 allele where as Channel Island breeds such as Guernsey and Jersey have more of A2 allele. It is also interesting to note that most of the Indian breeds of animals have only β-CN A2 allele. The present study was undertaken to characterise the β-CN gene polymorphism in Vechur and crossbred cattle of Kerala considering its public health importance. Blood samples were collected from 72 Vechur cattle, and 14 Kasargode Dwarf cattle available in the KAU farm and 100 crossbred cattle randomly selected from different parts of Kerala. Genomic DNA was isolated by standard phenol chloroform procedure. Beta casein A1 A2 polymorphism was analysed by Allele Specific Polymerase Chain Reaction (AS-PCR). The genotypic frequencies of A1A1, A1A2 and A2A2 were, respectively, 0, 0.40 and 0.60 in Vechur cattle, 0.32, 0.28 and 0.40 in crossbred cattle and 0, 0.79 and 0.21 in Kasargode cattle. Genotypic frequencies were not found to be in Hardy-Weinberg equilibrium in crossbred cattle while in Vechur and Kasargode cattle frequencies were found to be in equilibrium. The A1 and A2 allele frequency was 0.20 and 0.80 in Vechur cattle, 0.46 and 0.54 in crossbred cattle and 0.39 and 0.61 in Kasargode cattle. Comparison of allele frequencies revealed that there is significant variation in allele frequencies among these three groups of animals. The relationship between β-CN A1/A2 polymorphism with milk yield was also assessed. The average daily milk yield was 1.27±0.05 kg in Vechur cattle. The peak yield of crossbred cattle was 10.71±1.046 kg. The average daily milk yield for A1A2 genotype in Vechur cattle was 1.52±0.08 kg and 1.14±0.04 kg for A1A2 genotype. The t-test showed the difference in the milk yield of the two genotypes was significantly different at 5% level of significance. In crossbred cattle the peak yield (kg) of A1A1 genotype was 14.64±3.181, 8.54±0.194 for A1A2 genotype and 9.09±0.125 for A2A2 genotype. The A1A1 genotype in crossbred cattle showed significantly higher average peak yield compared to other genotypes and difference between A1A2 and A2A2 genotypes were not significantly different. From the present study it can be concluded that selection for enhancing milk production may increase the frequency of harmful A1 allele in our bovine population. So efforts should be taken to enhance the A2 allele with a view of transforming our cattle population capable of producing A2 variant of β-CN which has a global demand. The information generated in this study on the genotypes of Vechur and Kasargode dwarf cattle can be very effectively used for developing a herd/breed of cattle with A2A2 β-CN genotype.
  • Thumbnail Image
    ThesisItemOpen Access
    Genetic resistance to gastro-intestinal nematodes in goats
    (College of Veterinary and Animal Sciences, Mannuthy, 2010) Aparna, Sankar; KAU; Radhika, G
    The present study aimed at exploring the possibility of incorporating Gastro Intestinal Nematode (GIN) resistance as a criterion for selection in goat breeding. Here Faecal Egg Count (FEC) was taken as an indicator of host resistance. Heritability estimate for FEC and correlation of FEC with Packed Cell Volume (PCV) were calculated. While assessing resistance at phenotypic level using FEC as indicator, the possibility of using PCV as an alternative to FEC was also considered. Using IFNγ intron 1 as the locus of study, an attempt was made to identify a genetic marker for GIN resistance in goats. University Livestock Farm, Mannuthy and two field centers under All India Co-ordinated Research Project (AICRP), namely - Tellichery and Badagara, formed the venue for study. In the present investigation, data from three genetic groups - Malabari, Attappady Black and Malabari crossbreds were used. Representative population in the study comprised of 150 goats. The nematode eggs encountered during the study belonged to Strongyle and Strongyloides sp. Mean FEC was 764.39 eggs per gram of the faeces (epg) with values ranging from 0.00 to 16700 epg. The value of PCV estimated ranged between 19 and 48 per cent. Effect of non-genetic factors on FEC was analyzed after logarithmically transforming the FEC. University Goat & Sheep farm, Mannuthy recorded the least FEC. This might be due to the improved immune status of the animal through careful selection along with scientific managemental practices followed in the University farm. The non-significant influence of sex, birth weight and type of birth might be due to uniform managemental conditions given to kids irrespective of sex, birth weight or type of birth, which do not favour GIN prevalence. The reason for failure of season in influencing FEC could be due to the fact that, not much demarcation was observed between seasons during the study. The genetic similarity between Malabari purebreds and Malabari crossbreds, lesser sample size for Attapady Black breed and similar management given to the breeds led to non significant effect of breed on FEC. A negative phenotypic correlation estimate of -0.1791 was observed between LFEC and PCV. The heritability estimated for FEC was 0.39 ± 0.3630 as per paternal half sib correlation method and it was moderate. This moderate heritability estimate for FEC shows that there is significant genetic variation within the population for the trait, which makes selection for nematode resistance possible. Genomic DNA was isolated from blood samples of 150 goats maintained in the farm and two field centers of Kerala using phenol chloroform extraction procedure. Through PCR, a 202bp product of IFN γ intron 1 was amplified. On restriction digestion of the amplified product, the restriction-endonuclease, BspHI cut PCR product into two fragments of 180 bp and 22 bp sizes. Monomorphic pattern was observed on the particular RFLP analysis. The 202bp PCR product was sequenced by the dideoxynucleotide sequencing method with M13 universal reverse primer using an automated DNA sequencer. The sequence included a tetra nucleotide repeat, (GT4)5 and an Adenine present at a position, 49 bp downstream of this microsatellite. The sequence had 100 per cent homology with sheep, 89 per cent with European cattle, 73 per cent with pig and 70 per cent with human. On submission of the nucleotide sequence data of goat-IFNγ intron1 to the GenBank DNA database, an Accession Number: HM047072 was obtained. As per available literature, this work seems to be the first of its kind in establishing the DNA sequence data of intron1 of IFN γ gene in goats. It is recommended that study of this gene in a larger population with greater genetic base might bring out the polymorphism and help in marker assisted selection for GIN resistance in goats. Overall, the study aided in establishing nucleotide sequence of IFN γ intron1 in goats and showed that there is immense scope for selection of animals for nematode resistance. This study emphasizes the fact that along with other production traits, host genetic resistance should also be included as a criterion for selecting goats, producing genetically superior stock.