Small RNA are short, 18-25 nt molecules that regulate gene expression in plants and animals. Two main types, microRNA (miRNA) and short interfering RNA (siRNA) perform this regulation by transcript silencing, translation inhibition, DNA methylation and chromatin remodeling. This thesis is an investigation into small RNA activity in archaeological plant material, specifically barley grain from Qasr Ibrim, a multi-period archaeological site in southern Egypt. It is of particular interest due to its unusual phenotype, suggestive of stunted development that is unexpected in a staple, domesticated cultivar, and the unusual level of DNA and RNA preservation attributable to the extremely arid climate at the site. The research presented here is a comparative analysis of small RNA profiles and epigenetic states of Qasr Ibrim barley and modern, unstressed counterparts. It concludes that differential microRNA and epigenetic profiles are the result of stress response, adaptation, dormancy and / or viral infection unique to the archaeological grain. The primary method of investigation was generation of small RNA sequence data using the Illumina GAIIx platform. This was followed by extensive bioinformatic analysis (RNA diagenesis patterns, miRNA prediction, siRNA target prediction and small genome in silico reconstruction) the results of which were in turn validated experimentally (genomic methylation states, locus-specific methylation analysis and direct miRNA detection). The research represents a twofold contribution to knowledge: first, proof-of-principle that biologically meaningful archaeological RNA can be extracted despite its relative instability to DNA, and second that a unique miRNA profile and epigenetic state is detectable in this particular cultivar of archaeological barley.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:582308 |
| Date | January 2012 |
| Creators | Smith, Oliver |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/57032/ |
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