Systematics Section / ASPT
Margheim, Stephanie R. , Feysa IV, Peter M. , Murphy, Nicole , Raubeson, Linda A. .
Chloroplast genome rearrangements in Pinaceae.
BASED on the work of others, we know that Pinaceae chloroplast genomes are rearranged. Early mapping studies showed that these genomes have lost one copy of the large (20-25kb) inverted repeat common to other land plant genomes and have other changes in gene order. When the Pinus thunbergii (PITH) genome was completely sequenced, these changes were confirmed and additional changes were detected. In this study, we are looking at how these changes are distributed throughout Pinaceae. In the PITH genome there is a small remnant inverted repeat (ir) of 495 base pairs. We wanted to see if other members of Pinaceae had this ir, so we compared the two regions that might contain it by PCR and sequencing. So far, we have determined that the small ir is present in Pinus monticola, Larix occidentalis, Picea sp., and Tsuga heterophylla. These species are widely distributed within Pinaceae, suggesting that the ir is present throughout the family. In Tsuga, the IR is similar in size (410 bp) and content to the PITH ir. Other rearrangements in the pine genome are represented by five locations where genes that are normally together are no longer adjacent, indicating break points of inversions. To determine the distribution of these gene rearrangements, a PCR strategy is being applied. Different combinations of primers are used and the gene order is indicated by which combination produces product. For example, if the rrn16 primer and trnT primer produces a product, then trnT is adjacent to rrn16 (as it is PITH), whereas if the trnE and trnT primers produce a product, then trnT is adjacent to trnE (its normal location outside of Pinaceae). So far, no non-Pinaceae has been found to share any rearrangements with PITH. Likewise, no Pinaceae tested has not shared the PITH gene order.
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1 - Central Washington State University, Department of Biological Sciences, Ellensburg, Washington, 98926-7537, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM