A neuroepigenomic investigation of DNA methylation in cattle with extreme measures of docility

Conference Year

January 2019

Abstract

DNA methylation has been shown in rodents and humans to promote variation in behavioural phenotypes. It is unknown if DNA methylation in the bovine brain contributes to phenotypic variation in docility. Initially, variation in global DNA methylation levels between tissues within the bovine brain were examined. Next, we examined methylation in the bovine brain at a single nucleotide resolution. Eight brains from cattle with extreme measures of docility (4 docile and 4 aggressive) were dissected for five functionally distinct regions of the brain. DNA was extracted for Whole Genome Bisulfite Sequencing with Illumina HiSeq, paired-end 150bp. Fastq sequencing files were trimmed with Trim Galore using a phred score of 20. Trimmed reads were aligned to a bovine reference index using BSseeker2 and the bowtie2 aligner. BSseeker2 was further used to call for methylation levels. Coverage statistics were determined in CGmap Tools. Differentially methylated regions between docility phenotypes were identified with RADmeth. An average alignment coverage of 15.9X was obtained across all samples. Average DNA CG methylation ranged between 70.91% to 72.67% in all cattle, 70.17% to 72.98% in docile cattle, and 71.57% to 73.3% in aggressive cattle between brain tissue types. No significant differences were found in average DNA CG methylation between aggressive and docile cattle for any tissue type (P<0.05). Further analysis of differentially methylated regions will allow for an understanding of genomic regions of interest for future research in the environmental impact on bovine behavior.

Primary Faculty Mentor Name

Stephanie Mckay

Secondary Mentor Name

George Liu

Faculty/Staff Collaborators

Shuli Liu (Co-first Author), Nathan Jebbett, Robert C. Switzer III, Eugene Delay, Steven Zinn, Sharon Aborn, Jane O’Neil, Julia Sjoquist, Joseph Waksman, Hannah Lachance, Brenda Murdoch, Rick Funston, Robert Weaber, George Liu (Co Mentor), Stephanie McKay (Mentor)

Status

Graduate

Student College

College of Agriculture and Life Sciences

Program/Major

Animal, Nutrition and Food Sciences

Primary Research Category

Biological Sciences

Secondary Research Category

Food & Environment Studies

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A neuroepigenomic investigation of DNA methylation in cattle with extreme measures of docility

DNA methylation has been shown in rodents and humans to promote variation in behavioural phenotypes. It is unknown if DNA methylation in the bovine brain contributes to phenotypic variation in docility. Initially, variation in global DNA methylation levels between tissues within the bovine brain were examined. Next, we examined methylation in the bovine brain at a single nucleotide resolution. Eight brains from cattle with extreme measures of docility (4 docile and 4 aggressive) were dissected for five functionally distinct regions of the brain. DNA was extracted for Whole Genome Bisulfite Sequencing with Illumina HiSeq, paired-end 150bp. Fastq sequencing files were trimmed with Trim Galore using a phred score of 20. Trimmed reads were aligned to a bovine reference index using BSseeker2 and the bowtie2 aligner. BSseeker2 was further used to call for methylation levels. Coverage statistics were determined in CGmap Tools. Differentially methylated regions between docility phenotypes were identified with RADmeth. An average alignment coverage of 15.9X was obtained across all samples. Average DNA CG methylation ranged between 70.91% to 72.67% in all cattle, 70.17% to 72.98% in docile cattle, and 71.57% to 73.3% in aggressive cattle between brain tissue types. No significant differences were found in average DNA CG methylation between aggressive and docile cattle for any tissue type (P<0.05). Further analysis of differentially methylated regions will allow for an understanding of genomic regions of interest for future research in the environmental impact on bovine behavior.