Dear Prof. Golding, Thanks for your posting of my question. Here I send you the answers I got for past days. Would you please also paste it to all the evoldir colleagues? I think there should be some other colleagues also interested in this question. In addition, I am still looking for further kind replys and answers/examples for my question. I do hope to find more information concerning it. Thanks are also given the colleagues for sharing the ideas and literatures. Best Regards Jinyong jinyong.hu@googlemail.com >>>>>"bull@bull.biosci.utexas.edu" Dear Jinyong, Some years ago, Ric Charnov and I published a paper on the idea that some types of evolutionary pathways were difficult to reverse. The idea was similar to Dollo's law, and we discussed several examples. We did not mention molecular data, but such data might be attainable for some of those examples now. Jim Bull, J. J., and E. L. Charnov. 1985. On irreversible evolution. Evolution 39: 1149-1155 >>>>>>Beverly Ajie Hello Jinyong, I've passed your post along to a group I know thinking about relaxed selection and trait loss/loss of function on a theoretical level. They have been discussing just this issue and hopefully can provide some empirical examples for you. I would be very interested to hear what examples you receive from the community as a whole. If its not too much trouble, would you mind passing them along to me or reposting them to the evoldir list? Thank you and good luck, Bev Beverly Ajie Center for Population Biology University of California, Davis bcajie@ucdavis.edu >>>>>>jspagna@berkeley.edu "jspagna@berkeley.edu" Dear Dr. Hu, Please find attached my manuscript (to be published in Molecular Phylogenetics and Evolution, in the next 3-4 weeks or so) about the loss of function of a complex spider spinning organ: while this is a morphological feature, it is clearly lost more often than it has been gained (in fact, lost several times, and probably not regained) in spiders. The phylogeny is based on molecular data. Good luck with your examples, Dr. Joseph Spagna University of Illinois, Urbana-Champaign Urbana, Illinois 61801 >>>>>>David Shuker Dear Jinyong, Re. your Evoldir post. I am not sure if I have read your post correctly, but what you seem to be saying falls dangerously close to the fallacy of comparing the ease with which you can de-construct a trait (e.g. through loss of function mutations) with how hard it would seem to be to put together such a trait in its current form. But, of course, evolution does not work in the way envisaged by the latter. Complex traits do not just appear in some strangely well-developed way with a complex genetic architecture underlying them - when these traits start evolving, there is no "complex system" underlying them yet. So the problem you highlight does not really exist. For a far more detailed discussion of this kind of thing, read for example Mike Lynch's account of the evolution of protein function (Lynch (2005) Protein Science 14: 2217-2225) and recent explanations for the evolution of bacterial flagella (apparently considered by ID proponents to be "impossible" to evolve because of its complexity). There has also been a recent PNAS supplement on this kind of thing I think. I'd read those. Best wishes, Dave Shuker >>>>>>Paul Sunnucks hi the sexual-->asexual literature might be helpful. eg see attached Paul Dr Paul Sunnucks Senior Lecturer in Zoology Molecular Ecology Research Group and Australian Centre for Biodiversity: Analysis, Policy & Management School of Biological Sciences Monash University, Melbourne Clayton Campus 3800 Victoria Australia ph + 61 3 9905 9593 fax + 61 3 9905 5613 email paul.sunnucks@sci.monash.edu.au webpage: http://www.biolsci.monash.edu.au/staff/sunnucks/index.html >>>>>>naylor@scs.fsu.edu" Dear Jinyong, Your argument is interesting, but does not accommodate the fact that most architectures are highly redundant and robust. Life systems usually employ many-to-one (genotype to phenotype) mapping functions. Such architectures confound an experimenters capacity to unravell what is important and what is not. A large part of the configuration space may result in no effect on the phenoype whilst a few rare configurations may be highly sensitive to purturbation. Best of luck with your project. It looks interesting! Gavin Naylor >>>>>>>Juliette de Meaux Hi Jinyong! May be you should look into the flavonoid literature (Zufall & Rausher). There are abundant examples of evolution by loss of function. In the papers I gave you yesterday, there is evolution by gain of function (a longer protein is generated) which results in a loss of function (an interaction with other regulators of the clock becomes weaker). Hope that helps, xx J. >>>>>>>>Markus Pfenninger Hi Jinyong, here's an example of snails having lost their hairs on the shell at least twice, but no (re)gained them. http://www.biomedcentral.com/1471-2148/5/59 Of course I think that it's much easier to loose complex features than to (re)gain them. I'd even dare say that the frequence of loss might be an indicator of the trait complexity (after having discounted the ecological circumstances that favour the loss). In other words, complex features are only maintained by strong stabilising selection, otherwise they are lost. Best wishes for your work, Markus -- PD Dr. Markus Pfenninger Abt. Ökologie & Evolution J.W.Goethe-Universität BioCampus Siesmayerstraße D 60054 Frankfurt am Main Germany Tel.: ++ 49 69 798 24714 Fax : ++ 49 69 798 24910 eMail: Pfenninger@bio.uni-frankfurt.de http://user.uni-frankfurt.de/~markusp >>>>>>>>Brian Golding Before I forward your email I would like to understand a little better. All that you have to look at is any mutation database, or even go to hospital records and you see loss-of-function changes every day in every organism. Of course they are more common than gain-of-function which are incredibly rare. Simply look at any cave organism, or any bacterial endoparasite ... hundreds of loss-of-function and no gain-of-function. Brian >>>>>>>>m.zarowiecki@nhm.ac.uk Loss of function is easy: A single mutation can make a huge mess; several SNP-mutations at functional sites are known causes of genetic diseases in humans. The reason why there are not more of them is that they reduce fitness, and are therefore lost or kept at low frequency. You also have all the animals that change lifestyle; like parasites or cave-dwellers, that evolve from free-living animals. They may have had eyes, gut, pigmentation, but they do not longer need it. Then either active or passive loss (active dispute) leads to the degeneration of the organ, and resources are allocated elsewhere. Nothing makes sense except for in the light of evolution, well met, Magdalena jinyong hu