Hair and Nail RNA


About This Project


Keratinized tissues like the hair follicle and the nail are utilized to study historical and cumulative exposure of an individual to its environment and may serve as important, easily accessible tissues to identify disease biomarkers. As hair and nails grow, progenitors located at the base of the hair follicle and in the nail matrix cease cell division, terminally differentiate, and die, becoming the external hair shaft and nail plate, respectively. The hair and nail offer different advantages in the diagnosis of disease-induced changes and environmental stress: hair is long and provides a cumulative method of identifying transcriptional changes (previous analysis of human hair suggests potentially months of data can be obtained); while hair may not always be in its growth phase and non-growing hair will not provide continuous transcriptional responses, the nail unit is a continuously growing keratinized tissue, potentially allowing for continuing monitoring environmental stress.

RNA is the common message of all organisms. Detection and analysis of RNA is a focal point of evolutionary biology and personalized medicine as many RNAs, both protein-coding and non-coding, contribute to adaptive mechanisms and disease, or serve as gene expression markers for diagnosis, therapeutic monitoring, or environmental exposures. Recent research suggests that RNA is highly stable in human hair, and readily accessible for advanced molecular studies, including real-time PCR and high-throughput sequencing. Preliminary studies utilizing high-throughput sequencing to determine whether RNA is stable in other keratinized tissues yielded similar results: a small RNA library generated from human nail revealed that thousands of coding and non-coding RNAs persist in distal keratinized portions of the nail. Genome-wide comparison of nail, hair and keratinocyte RNA revealed unique and overlapping patterns of gene expression. We will use this methodology to explore evolutionary implications of “dead transcriptomes” – RNA recovered from hair, nails, talons, feathers, and scales of multiple species, including opossum, polar bears, chimps, and wooly mammoths. One of our goals is to explore transcriptomes of endangered and long-gone species and reconstruct phylogenetic relationships by utilizing non-invasive sampling of relatively-well preserved keratinized tissues.

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