ASSOCIATION OF SINGLE NUCLEOTIDE POLYMORPHISMS IN THE QUANTITATIVE TRAIT LOCI WITH RESISTANCE OR SUSCEPTIBILITY TO TICK INFESTATION IN CATTLE
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Date
2019-10-05
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
The present study was aimed to identify the polymorphisms in five QTLs that
were reported to have an association with resistance/susceptibility to tick infestation
in cattle and to find out the association of SNPs with tick infestation in cattle. It
was also intended to study the effect of season on the association between the SNPs
and tick infestation in cattle. The population under study comprised 45 Vechur and
74 crossbred cattle from the farms of Kerala Veterinary and Animal Sciences
University. The QTLs and SNPs were selected from the QTL database, Animal
QTLdb. The SNPs and the QTLs (in parenthesis) used in this study were:
rs41661020 (#101148), rs109162468 (#101169), rs43708490 (#135798),
rs41577070 (#135800) and rs29009970 (#135801). Blood samples were collected
from the animals and the genomic DNA was isolated and used for genotyping and
polymorphism study by PCR-RFLP assay and confirmed by sequencing.
Genotyping was done by direct counting and the allelic and genotypic frequencies
were estimated by POPGENE 1.32. The results revealed a monomorphic pattern
for the SNP rs109162468 and polymorphic pattern for the SNPs rs41577070,
rs41661020, and SNP rs43708490 in the population under study. The SNP
rs29009970 was monomorphic in the crossbred cattle, whereas, dimorphic in
Vechur. The Chi-square test revealed that crossbreds and Vechur were in HWE for
SNPs rs41577070, rs41661020, and rs43708490, whereas, the SNPs rs29009970
showed a significant departure from the equilibrium. For the association study, tick
counts were taken during summer (March to May) and rainy (June to August)
seasons from the animals using Wharton and Utech (1970) method. However, no
tick infestation could be seen in any animals during the period of study. Hence, all
the 119 animals were grouped in the class: no infestation and the analysis to find
the association of SNPs with tick infestation and the effect of the season on the
SNP-tick load relationship in cattle could not be carried out.