Thumbnail Image

Thesis

Browse

20153
Reset filters
Subject: Animal Genetics and Breeding × End date: 2015 × Start date: 2015 ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON GENETIC VARIABILITY IN NELLORE BROWN SHEEP USING MICROSATELLITE MARKERS
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2015) SHEELA MANJARI JONNA KUTTI, JONNA KUTTI; PUNYA KUMARI, B(MAJOR)
    ABSTRACT: Nellore sheep is the tallest mutton breed of India and its home tract is Nellore and Prakasam districts of Andhra Pradesh, but widely distributed throughout the state of Andhra Pradesh and parts of Telangana. Three varieties are distinguished phenotypically based on coat colour as Palla (completely white), Jodipi (white with black patches) and Dora/Brown (completely brown). Nellore Brown sheep are predominantly present in Rayalseema region (Kadapa, Kurnool, Anantapur districts) of Andhra Pradesh. This breed is well known for its disease resistance and thrives well in harsh climatic conditions of Rayalseema. The assessment of genetic variability is important to monitor the gene flow in populations, for conservation of breed and also to determine the level of inbreeding in the population. The present study was undertaken to evaluate the genetic variability present in Nellore Brown sheep population by using twenty four microsatellite markers from the panel of markers recommended by ISAG-FAO for the genetic diversity studies in sheep. A total of fifty blood samples were collected at random from unrelated Nellore Brown animals maintained by farmers in its breeding tract. Phenol-chloroform method was used for isolation of DNA from blood samples. The quality and quantity of isolated DNA was checked using gel electrophoresis and Nanodrop spectrophotometer, respectively. The PCR products were resolved using agarose gel electrophoresis. The allele size for each locus was scored manually from the electrophoresed gels. The allele frequencies, observed number of alleles (Na), effective number of alleles (Ne), observed (Ho) and expected (He) heterozygosity, within population inbreeding estimates (FIS) were computed using POPGENE version 1.32 software. A total of 216 alleles were identified across all the twenty four microsatellite loci studied. The number of alleles at each locus varied from a minimum of four (HUJ616) to a maximum of thirteen (OarCP49) with a mean of 9.0 alleles across all loci. Allele size ranged from a minimum of 75 bp (OarCP49) to a maximum of 297 bp (HSC), while allele frequencies ranged from 0.0102 to 0.3980. The most frequent allele number was nine. The number of effective alleles ranged from 3.8757 (HUJ616) to 9.6232 (OarCP49). The mean number of effective alleles with an overall mean of 6.78 ± 1.79 alleles. The observed heterozygosity ranged from 0.0408 (BM1314) to 0.1429 (OarHH35, OarHH41) with a mean value of 0.0985 ± 0.025, whereas, the expected heterozygosity ranged from 0.7420 (HUJ616) to 0.8961(OarCP49) with a mean value of 0.8409 ± 0.046. All the twenty four microsatellite loci (100 percent) were found to be highly polymorphic and the PIC values ranged from 0.6945 (HUJ616) to 0.8961 (OarCP49) with a mean PIC value of 0.8240 ± 0.061. The inbreeding estimates obtained in this study were all positive and varied from 0.8318 (OarHH35) to 0.9534 (BM1314). The mean FIS value of 0.8825 ± 0.03 indicated the deficiency of heterozygotes. The Chi-square test revealed that all the twenty four loci were showing significant deviation from Hardy-Weinberg Equilibrium.
  • Thumbnail Image
    ThesisItemOpen Access
    MOLECULAR GENETIC CHARACTERIZATION OF NELLORE SHEEP
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2015-01) SUREKHA, J; Punya Kumari, B(MAJOR); Gnana Prakash, M; Suresh, J
    ABSTRACT : Nellore sheep is the tallest sheep breed of India whose home tract is Nellore and Prakasam Districts of Andhra Pradesh, but distributed throughout Andhra Pradesh and in certain areas of Telangana state. Nellore is a meat type breed known for heat tolerance, disease resistance and thrives well in harsh climatic conditions. The assessment of genetic variation is important to monitor the gene flow in populations, for conservation of breed and also to determine the level of inbreeding in the population. The present study was carried out to characterize Nellore sheep at molecular level to understand the genetic constitution of population, properly asses the value of breeds and to guide decision making in livestock development and breeding programmes. The characterization was done by fifteen microsatellite markers recommended by FAO for population diversity studies in sheep. DNA was isolated from blood samples by phenol-chloroform method and microsatellites were amplified by Polymerase Chain Reaction. The PCR products were resolved using agarose gel electrophorosis. The genotypes were scored and the number, size, frequency of alleles was calculated using POPGENE software. In the sampled population for the fifteen marker loci under investigation a total of 129 alleles were observed. The number of alleles at each locus varied from a minimum of four to a maximum of twelve with a mean of 8.6 alleles across all loci. Allele size ranged from a minimum of 78 bp (OarCP49) to a maximum of 294 bp (HSC), while allele frequency varied between 0.0104 (MAF214) to 0.5102 (OarHH64). The most frequent allele number was eight. The number of effective alleles across fifteen microsatellite loci studied ranged from 2.6027 (OarHH64) to 9.0530 (MAF214). The mean number of effective alleles was 6.766 ± 0.461 across all loci. The expected heterozygosity ranged from 0.6221 (OarHH64) to 0.9022 (OarJMP8) with a mean value of 0.837 ± 0.018, whereas, the observed heterozygosity ranged from 0 (BM827, OarHH41, BM6506 and HUJ616) to 0.3061 (OarCP34) with a mean value of 0.098 ± 0.025. All the fifteen microsatellite loci (100 percent) were found to be highly polymorphic and the PIC values ranged from 0.5465 (OarHH64) to 0.8951 (MAF214). The mean PIC value for all the fifteen loci was found to be 0.819 ± 0.21. The Chi-square test revealed that all the fifteen loci were showing significant deviation from Hardy-Weinberg Equilibrium. The inbreeding estimate values obtained in this study were all positive and ranged from 0.6300 (OarCP34) to 1.000 (BM827, BM6506, HUJ616 and OarHH41). The mean FIS value was 0.919 ± 0.025 indicating the deficiency of heterozygotes.
  • Thumbnail Image
    ThesisItemOpen Access
    MICROSATELLITE MARKER BASED ASSESSMENT OF GENETIC STRUCTURE OF MACHERLA BROWN SHEEP
    (SRI VENKATESWARA VETERINARY UNIVERSITY, TIRUPATI – 517502. (A.P.) INDIA, 2015-12) MOHAN KISHORE, MOLABANTI; Punya kumari, B (Major); Jaya laxmi, P; Suresh, J
    ABSTRACT: Macherla Brown sheep is the native sheep distributed along the banks of river Krishna flowing through Guntur, Krishna, Prakasam and Nalgonda districts of Andhra Pradesh and Telangana states. The home tract is mainly from the Nagarjuna sagar dam areas of Guntur and Nalgonda. Macherla Brown is known for heat tolerance, disease resistance and thrives well in harsh climatic conditions and scarce feeding conditions. The assessment of genetic variation is important to characterize the populations for breed recognition, conservation and also to determine the level of inbreeding in the population. The present study was carried out to assess the genetic structure of Macherla Brown sheep at molecular level to understand the genetic variability and diversity of population and to recognise this high performing local variety of sheep as a breed. Twenty four ovine microsatellite markers recommended by ISAG/FAO for population diversity studies in sheep were used in the present study. Phenol-chloroform method was used for the isolation of DNA from the collected blood samples and the microsatellite markers were amplified by PCR reaction. The amplicons were identified using agarose gel electrophoresis. The genotypes were scored using regression equation of the 100 bp DNA standard. The number, size and frequency of alleles were calculated using POPGENE version 1.3.2 software. A total of 275 alleles were observed for the twenty four marker loci under investigation in the sampled Macherla Brown population. The number of alleles at each locus varied from a minimum of eight (BM6506, HSC, OarCP34) to a maximum of eighteen (MAF214) with a mean of 11.458 alleles. Allele size ranged from a minimum of 69 bp (OarCP20) to a maximum of 313 bp (MAF214), while allele frequency varied between 0.0102 (HSC, INRA63, MAF214, OarP49 and OarVH72) to 0.2551 (HSC). The number of effective alleles across twenty four microsatellite loci studied ranged from 5.8065 (HSC) to 14.1652 (OarFCB48). The mean number of effective alleles was 9.597 ± 2.454. The observed heterozygosity ranged from 0.0612 (BM8125) to 0.2653 (OarCP34) with a mean value of 0.110 ± 0.049 whereas, the expected heterozygosity ranged from 0.8278 (HSC) to 0.9294 (OarFCB48) with a mean value of 0.889 ± 0.029. All the twenty four microsatellite loci (100 percent) were found to be highly polymorphic and the PIC values ranged from 0.8052 (HSC) to 0.9295 (OarFCB48). The mean PIC value for all the twenty four loci was found to be 0.882 ± 0.036. The Chisquare test revealed that all the twenty four loci were showing significant deviation from Hardy-Weinberg Equilibrium. The inbreeding estimates obtained in this study were all positive and ranged from 0.6915 (OarCP34) to 0.9341 (OarFCB48) with the mean FIS value of 0.876 ± 0.057 indicating the high deficiency of heterozygotes.