Generation of an Equine Tissue Biobank for Functional Annotation

The Functional Annotation of the ANimal Genome (FAANG) project aims to identify functional regulatory elements in animal genomes in both sexes and across multiple stages of development. For the horse, a biobank of tissues and cells was created including 86 tissues and three cell types from two adult mares. Both mares were deemed healthy after undergoing clinical evaluations including full physical examinations, lameness, ophthalmologic and neurologic evaluations and complete blood counts, and serum biochemistries were performed. At necropsy, in addition to tissue samples, multiple aliquots of serum, whole blood, plasma, cerebrospinal fluid, synovial fluid and gastrointestinal contents from all regions of the gastrointestinal tract and urogenital tract were collected. Keratinocytes, fibroblasts and melanocytes were cultured. All tissues were grossly and histologically evaluated by a board-certified veterinary pathologist. Biobank samples were collected adjacent to the site evaluated for histopathology, thereby providing histological correlation of the cellular makeup for each tissue. Each sample was then preserved in liquid nitrogen or fixed for Chromatin Immuno-Precipitation SEQuencing (ChIP-seq). Nuclei extraction was performed on 16 tissues for DNase-I hypersensitivity Sequencing (DNAse-Seq). Eight tissues (cerebral cortex, left ventricle of the heart, hoof lamina, liver, lung, ovary, spleen, and longissimus dorsi skeletal muscle) were prioritized for initial RNA sequencing (RNA-seq) and ChIP-seq. As a larger collaborative effort, 15 other laboratories have identified a tissue of interest to support for the initial RNA-seq effort. This extensive biobank will be used to create a tissue-specific atlas of gene expression and regulation in the horse.