As proposed by Posada & Crandall [ 53] this haplotype should represent the most ancestral one, whereas the most derived ones are related to it with a maximum branch length of twelve mutational steps (H55 and H52).
This is the mode of development for most complex bilaterians, except derived ones, such as Echinoderms and Urochordates (Holland, 2002; Mooi and David, 2008).
For example, it assumed that in every speciation event, the species that retained the ancestral ("plesiomorphic") characteristics stayed closer to the original area, while the most derived ("apomorphic") species was the one that dispersed (Crisci et al. 2003; Cox and Moore 2010).
A vicariance biogeographic interpretation of these distribution patterns is further weakened by fossil data: the oldest known fossil of the family Syngnathidae (of which seahorses are considered to be one of the most derived genera by virtue of their advanced brood pouch morphology [ 66]) is less than 50 my old [ 67].
This is corroborated to some extent by this study, but most derived sabrecats are larger than primitive ones, clouding this image.
However, it can be challenging to derive one's intentions.
The genetic information obtained is, for most sequences, derived from just one strain, and may therefore be strain specific, as shown for a number of L. monocytogenes genes (Nelson et al., 2004).
Mr. McNerney said the new version of the 777, which is still subject to final approval by Boeing's board, would include much more substantial improvements than most planes derived from existing ones and could be ready by the end of the decade.
Most degradome tags were derived from one NAT transcript: 53.3% (65) cis-NATs, and 50.2% (2,222) trans-NATs, generated tags from only one transcript.
