Jean, While not on epigenetics per se here's some notes on polyploid evolution: http://www.public.iastate.edu/~mbhattac/bhattacharyya/polyevolution.pdf
An interesting theory, proposed by Soltis and Soltis, that all angiosperms originally had something like 8 chromosomes and through naturally occuring accidents in gametogenesis over the ensuing billion years (I exaggerate the timeline) angiosperms now have as many chromosomes as they do because the polyploid 'accidents' out compete the plants with normal 'n' numbers. Also that 'they' (whoever 'they' are) now believe these accidents in gametogenesis occur more frequently than originally was thought. I haven't truly followed through to google more info on Soltis & Soltis. Did you see 'they've' traced house cats back to 5 'Eve's' from Mesopotamia? Not Egypt after all. http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=464985&in_page_id=1770) K Barrett N Calif, USA > >Does anyone know if anyone has looked at or considered any epigenetic >effects in orchids? We all know that the rapid accumulation of DNA data on >species and subsequent groupings into clades is/has led to turning many >genera (and orchid judges and enthusiasts) on their heads. On the other >hand >there are a lot of cases where morphology doesn't quite match that so the >next question is, if for instance there is a lot of rapid speciation going >on in places like Ecuador (Hirtz), then is it possible that some of this >so-called speciation could be epigenetic effects brought on by intense and >in a historical perspective 'sudden' environmental changes like >deforestation or climate change. I guess the key word is rapid, which is >why >I asked the second question about epigenetic effects because if any of >these >new 'species' are really epigenetic changes that may only last a few >generations because they are epigenetic and not as stable as DNA changes, >then how is the taxonmist barely hanging onto a wet hillside in the field >Ecuador to know what is a real species or not (given something that looks >new is really an epigenetic effect). >I have pondered this since the magazine Nature had a series of featured >articles on epigenetics a couple of months ago. >Jean Allen-Ikeson in Nova Scotia, Canada _________________________________________________________________ http://liveearth.msn.com _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
