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MOLECULAR GENETIC STUDIES ON NELLORE AND DECCANI SHEEP USING MICROSATELLITE MARKERS

KrishiKosh

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Title MOLECULAR GENETIC STUDIES ON NELLORE AND DECCANI SHEEP USING MICROSATELLITE MARKERS
 
Creator POTHUMUDI, AMARESWARI
 
Contributor Dr M. GNANA PRAKASH
 
Subject “Molecular Genetic Studies on Nellore and Deccani Sheep Using Microsatellite Markers
 
Description A total of 100 sheep, 50 each from Deccani and Nellore breeds were genotyped using 30 dinucleotide microsatellite marker primers. The genomic DNA was isolated using standard phenol-chloroform method. The mean optical absorbance ratio was 1.95 in both the breeds indicating good quality of genomic DNA.
A total of 254 and 260 alleles in Deccani and Nellore breeds were obtained with allele size range varying from 71 (OARCP20) to 288 (LSTS11) in both the breeds. The number of alleles ranged from 4 to 12 in Deccani with an average of 8.46 and 4 to 14 in Nellore with an average of 8.66. The effective number of alleles ranged from 2.135 to 9.580 in Deccani and 2.683 to 10.240 in Nellore whereas the overall mean effective number of alleles varied between 5.52 for Deccani and 5.62 for Nellore sheep. The allele frequency ranged from 1.0 to 65.6 per cent in Deccani and 1.0 to 51.1 per cent in Nellore sheep.
A total of 23 out of 254 and 37 out of 260 alleles amplified were found to be population specific for Deccani and Nellore sheep respectively. The overall mean PIC values ranged from 0.773 in Deccani to 0.777 in Nellore breed. Across the loci, the PIC values ranged from 0.587 to 0.886 in Deccani and 0.552 to 0.894 in Nellore breeds. The PIC values for all the loci were above 0.50 except for the loci OarHH35 (0.49) in Deccani.
The mean expected heterozygosity among the breeds ranged from 0.79 (Deccani) to 0.80 (Nellore) whereas the mean observed heterozygosity levels ranged from 0.77 in Deccani to 0.78 in Nellore sheep.
The overall mean inbreeding coefficient was 0.029 in Deccani and 0.031 in Nellore sheep. Of the 30 loci studied, 14 loci in Deccani and 16 loci in Nellore sheep showed negative inbreeding coefficient indicating the presence of outbreeding. Eight loci showed positive, mild to moderate inbreeding ranging from 0.007 to 0.25 in both the breeds studied. The FIS values ranged from -0.372 to 0.74, FST values ranged from 0.001 to 0.172 and FIT values ranged from -0.370 to 0.728 between the Deccani and Nellore sheep breeds studied. The unbiased expected heterozygosity in Deccani sheep ranged from 0.54 to 0.91 and in Nellore sheep, it ranged from 0.64 to 0.91.
The genetic distance was 0.225 and genetic identity was 0.799 between the two sheep studied. All the loci departed from the equilibrium frequency significantly in both the sheep breeds. This might be due to homozygote deficiency as the animals from both the breeds were selected from different regions across the states.
The results of this study contribute to the knowledge of genetic structure of Deccani and Nellore sheep. The results reveal high genetic variation within the breeds and hence the significant characters of the two breeds Viz., the dual utility of Deccani sheep and tallest character of the Nellore sheep makes it imperative to strengthen the conservation measures. Also, integrating genetic improvement programme with marker oriented production strategies will raise the economy of the farmers of this region.
 
Date 2017-01-04T12:00:30Z
2017-01-04T12:00:30Z
2015-07-09
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/94366
 
Relation D;419
 
Format application/pdf
 
Publisher PVNR TVU