rps14 gene status in 44 genera of Poales. The status of rps14 in either the mitochondrial (M) or nuclear (N) genomes is marked on a phylogenetic tree of Poales as follows: A dark "+" indicates that rps14 is an intact open reading frame over the length of the gene sequenced. A light "+" indicates that a nuclear rps14 sequence was not obtained by PCR, but is inferred to be present based on the absence of an intact rps14 gene in the mitochondrial genome of that species. A "ψ" indicates that only a pseudogene form of rps14 is present in the mitochondrial genome. A "-" indicates that rps14 is inferred to be absent from the mitochondrial genome based on negative slot blot and/or PCR results. A question mark indicates uncertainty as to whether an intact copy of rps14 is present in the nucleus because a functional copy was recovered from the mitochondrial genome and because repeated PCR attempts failed to yield a putative nuclear rps14 sequence. Red bullets mark three separate transfers of rps14 to the nucleus. The Joinvillea transfer is shown as very recent because of the nuclear gene's limited divergence (see text, Figure 3, and Additional File 1), whereas the other two transfers are arbitrarily positioned at the midpoint of their internodes. Black boxes mark mitochondrial sequences for which RNA editing information has been obtained (Table 1). The estimate of Poales phylogeny are based on GPWG (2001) , Kellogg (2001) , and Bremer (2002) .