Different RAW tone in Lightroom v. Aperture

I've also noticed that exporting the RAW file from Lightroom into Aperture results in the same differences in colour tone (i.e. the exported RAW file looks the same as the original file that was imported into Aperture, rather than as rendered in Lightroom).

When the exported RAW file is opened in Apple's Preview application the colour tone is identical to the Aperture rendering as well.  However, when I create a JPEG from within Lightroom, and open that in Preview, the colour tone is most similar to the Lightroom rendering of the RAW file.

This makes me think that Lightroom is handling the RAW file in a different way, but I can't work out how, or why!