The postulated genome-wide sequence cache
- The postulated genome-wide sequence cache ››
- Lolle and co-workers's paper is getting a lot of notice and generating a lot of talk (e.g. here). I concur with most people: it's weird! Carl Zimmer makes a good point on this: it's weird meaning "odd", not weird meaning "overturning everything we know and making a fool of Mendel". Anyway, I note that Lolle and co haven't produced any evidence that a very large duplication (bigger than the region covered by their Southern and their PCR amplicons) isn't involved, though the observed reversion rate at non-HOTHEAD positions presumably takes this into account. At one point they breezily write:
which suggests to me a possible function of the hth mutation (i.e. breakdown of the containment of this backup-restore mechanism in somatic cells, resulting in more germline read-from-cache activity). The cache is a fascinating thought:The frequency of apparent reversion events observed in embryos is somewhat higher than that observed phenotypically. We believe this probably reflects somatic reversion events occurring in embryonic tissues that do not contribute to the adult plant.
i.e. a sort-of multiple-choice trait inheritance, albeit at low frequency. This caching, if real and widespread, has big and interesting implications for all types of horizontal transfer (gene therapy, genetic engineering, provirus activity, transposons, etc) and events with confirmed genetic determinant (what price proto-oncogenes now?). However, not everybody thinks it is real and their arguments are strong (see especially the comments).The sequences [in the cache] would therefore represent a collection of alleles already known to be functional under at least some circumstances, and the restoration of these sequences to the DNA genome might represent a mechanism for the organism to recover from a genotype that was poor adapted to its present environment.
- [Permalink…27-Mar-05…Deserving memes……Comments (0)]
Comments
Movable Type 4.1 | 
feed (add to Google) (validate it)
| Creative Commons license | xml sitemap | xhtml1.0 | css | File under: life's wave, tanked by
Post a comment
Comments are moderated so please have patience. An email address is required but won't be shown or disclosed to anyone if I can help it because I don't like spam either.