Investigation of Information Accumulation in Escherichia Coli's DNA Sequence Affecting Mastitis in Dairy Cow Using Information Theory

Mastitis causes lots of cost annually in dairy farm enterprises of different countries. Mastitis caused by Escherichia coli is common in high-producing cows with low milk somatic cell count. The severity and effect of Escherichia coli mastitis vary between cows of the same herd and between different lactation stages in the same individual. The severe form of Escherichia coli mastitis is associated with loss of milk production and can outcome in death of the cow. As matter of fact that Escherichia coli bacterium plays enormous role in causing and expanding mastitis, in this research it was tried those DNA sequence segments of this bacterium involving in mastitis to be investigated using information theory.
In this study, first, Escherichia coli's DNA sequences related to mastitis in dairy cattle were downloaded from Genbank (NCBI) and saved in FASTA format. The DNA segment sequences were aligned. The amount of entropy, mutual information among nucleotides and Kullback – Leibler distance among DNA segment sequences were calculated using MATLAB software.
The results shown that entropy of DNA sequences were different in this bacterium but almost all of them had high amount of entropy (H(x) > 1.900). The absolute values of Kullback – Leibler distance indicated that DNA sequences investigated in this study were not similar. This might indicates that these DNA sequences could be involved in different metabolic networks, therefore, manipulating them - like silencing –might bring about unpredicted consequences. The results of mutual information turned up that DNA bases in different DNA sequence segments have different degree of association, which could transparent a type of linkage disequilibrium among different DNA bases.
In general, it was concluded that for managing mastitis, it is possible to single out those DNA sequences segments bearing up high amount of entropy as drug and biotechnological targets; since in this study it was assumed that those DNA sequence segments that exert high amount of entropy, would have higher degree of influence on mastitis in dairy cows.