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Genetic Polymorphism of STAT 5A, DGATI and CYP19 Genes and Their Association with Milk Production Traits in Cattle and Buffaloes

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Title Genetic Polymorphism of STAT 5A, DGATI and CYP19 Genes and Their Association with Milk Production Traits in Cattle and Buffaloes
 
Creator Sudhakar, Krovvidi
 
Contributor Pannerselvam, S.
 
Subject Genetic polymorphism
STAT5A
DGAT1
CYP19 genes
Milk yield, fat
SNF
Protein
 
Description STAT5A, DGAT1 and CYP19 genes are primarily related to hormonal metabolism,
physiology or reproduction and all are predicted to be candidate genes for milk traits influencing milk
production and composition. Hence the present study was undertaken to investigate the genetic
polymorphism of STAT5A, DGAT1 and CYP19 genes by PCR-RFLP and their association with milk
yield and milk constituents so as to use them as candidate genes. A total of 502 blood samples and
222 milk samples from different genetic groups comprising of Jersey crossbred, HF crossbred, Ongole
cattle and Murrah buffaloes were collected for the study in addition to data on lactation milk yield
from lactation records from organized farms. At the STAT5A/Aval locus frequencies of C and T alleles were 0.98 and 0.02 in Jersey
crossbred, 0.94 and 0.06 in Holstein Friesian crossbred and in Ongole they were 0.97 and 0.03,
respectively. No TT genotype was observed in the cattle populations studied. The analysis of
DGAT1/CfrI revealed K/A polymorphism in the crossbred cattle. The allele frequencies of K and A
alleles were 0.74 and 0.26 in Jersey crossbred and 0.60 and 0.40 in Friesian crossbred cows. The K
allele was fixed in Ongole cattle. CYP19/PvuII polymorphism was observed in all the three cattle
genetic groups. The frequency of allele A was 0.90, 0.88 and 0.77 in Jersey crossbred, Holstein
Friesian crossbred and Ongole cattle, respectively. The Murrah buffaloes in the examined population
were monomorphic to alleles C, K and B for the respective genes studied.
The cattle populations existed in Hardy Weinberg equilibrium at all the loci studied except
Jersey crossbred at DGAT1/CfrI. The PIC values varied from 0.038 to 0.106 for STAT5A, 0.311 to
0.365 for DGAT1 and 0.164 to 0.292 for CYP19 genes among the different cattle populations. The FIS
values were negative for all the genes in the three genetic groups except for DGAT1 (0.2054) in Jersey
crossbred.
The amplified fragments of STAT5A, DGAT1 and CYP19 were sequenced and various SNP’s
and nucleotide substitutions have been identified.
The association studies of the different genotypes of the three loci with the lactation milk
yield and milk constituents were carried out. The least squares mean lactation milk yield of CC and
CT genotypes of STAT5A were 2096.90 ± 48.63 and 2294.41 ± 215.85 kg in Jersey crossbred,
2312.92 ± 91.01 and 2392.82 ± 207.66 kg in HF crossbred and 528.40 ± 22.10 and 396.37 ± 76.17 kg,
respectively in Ongole cattle. The fat, SNF, protein and lactose content of CC genotype were 4.31 ±
0.39, 8.94 ± 0.14, 3.27 ± 0.05 and 4.90 ± 0.08 per cent, respectively and were higher than CT
genotype in Jersey crossbred cattle, whereas CT genotypes showed higher values in HF crossbred. In
Ongole cattle CT genotypes recorded more fat per cent (4.36 ± 0.58) than CC genotypes.
The least squares mean of lactation milk yield for KK, KA and AA genotypes of DGAT1/CfrI
were 2026.78 ± 59.14, 2132.45 ± 85.54 and 2357.59 ± 122.17 kg, respectively in Jersey crossbred
cattle. The corresponding values in HF crossbred were 1997.77 ± 167.66, 2373.26 ± 115.50 and
2493.77 ± 147.66 kg. In both the genetic groups the alanine variant (DGAT1A) were superior to lysine
(DGAT1K) variant for lactation milk yield. DGAT1 significantly (P
 
Date 2016-07-26T16:35:07Z
2016-07-26T16:35:07Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69972
 
Language en
 
Format application/pdf
 
Publisher Tamil Nadu Veterinary and Animal Sciences University