The LTEE. (oh and annother creationist gets trounced.)
Andrew Schlafly (Phyllis Schlafly's son) recently founded Conservap(a)edia. It is (as you might guess) an alternative to wikipedia because of the "liberal bias" it apparently has.
Dr. Richard Lenski is running the Long Term Evolutionary Experiment (LTEE). For the past 20 years he has been growing a culture of E. coli in a medium where glucose is the limiting growth factor. Lenski has twelve evolving populations , and every 500 generations samples are taken and frozen giving them a "fossil record" palaeontologists would sell their mothers to have. The aims of the LTEE is to observe patterns of contingency and convergence. So far the bacteria have been converging- they're considerably bigger than they used to be, and show a wide variety of other adaptations that have appeared in parallel. However...
With his collaborators, Zachary Blount and Christina Borland, Lenski has discovered that E. coli in one of the populations has evolved the ability to take up and metabolise citrate (known as Cit+). The citrate is in the medium to help the bacteria take up iron, but never normally enters the cell. Importantly E. coli can't eat citrate in aerobic conditions- its one of the defining characteristics of E.coli. (It seems there have been two other reports of Cit+ in E. coli and they've both come from swapping plasmids with other bacteria). The bacteria in the experiment lack plasmids, and only reproduce asexually. The scientists used their fossil record to investigate the process of Cit+ evolution, ruling out plasmids and contamination, and then tracking the process of Cit+ evolution. It seems there are at least 3 mutations involved, they didn't happen all at once, the earliest bacteria able to survive on citrate did so very poorly, and research remains to see what exactly is going on at the genetic level.
The paper is available online (pdf). You can also read abstracts and some pdfs from all the publications to come out of the LTEE.
The fact that one population is now significantly different from the others makes it very interesting to watch, because they've got a really visible, and important example of contingency. So lots to look forward to, and plenty more research to do. Carl Zimmer's been keeping a good blog on this, and Zachary was kind enough to turn up in the comments, offered to answer questions, and point people to other papers from the LTEE. Unfortunately a creationist turned up who didn't understand the meaning of the word "goal", so the whole thing turned into a car-crash. Zachary should have a guest post up there soon, dealing with some of the questions. (Excuse me I appear to be getting teary-eyed at a scientist engaging with the public- its so beautiful when it happens.)
Anyway, why did I mention Mr Schlafly? Well over at Conservapedia he wants Lenski to provide him with 20 years worth of data. He has it seems "skimmed" the paper and quoting PNAS's rules thinks he can demand this. Lenski politely points out that 1. the data is in the paper, and 2. he isn't saying what Schlafly thinks he's saying. This isn't enough for Schlafly, who complains that he must have access because they're taxpayer funded, and they sometimes say "data not shown". Lenski replies again, and I can't summarise it other than to say that Schlafly gets his arse handed to him on a plate. There are some beautiful quotes which I shall share, but you should read the exchange, at RationalWiki.
"If you have not even read the original paper, how do you have any basis of understanding from which to question, much less criticize, the data that are presented therein?"
"Am I or the reporter for NewScientist somehow responsible for the confusion that reflects your own laziness and apparent inability to distinguish between a scientific paper, a news article, and a confused summary posted by an acolyte on your own website?"
"But perhaps because you did not bother even to read our paper, or perhaps because you aren’t very bright, you seem not to understand that we have the actual, living bacteria that exhibit the properties reported in our paper, including both the ancestral strain used to start this long-term experiment and its evolved citrate-using descendants."
And for my American friends, an explanation of the differences between cricket and baseball. (It certainly explains why I understand cricket better than baseball.)
(Via Pharyngula, Bad Science, and pretty much everybody else by now.)
Dr. Richard Lenski is running the Long Term Evolutionary Experiment (LTEE). For the past 20 years he has been growing a culture of E. coli in a medium where glucose is the limiting growth factor. Lenski has twelve evolving populations , and every 500 generations samples are taken and frozen giving them a "fossil record" palaeontologists would sell their mothers to have. The aims of the LTEE is to observe patterns of contingency and convergence. So far the bacteria have been converging- they're considerably bigger than they used to be, and show a wide variety of other adaptations that have appeared in parallel. However...
With his collaborators, Zachary Blount and Christina Borland, Lenski has discovered that E. coli in one of the populations has evolved the ability to take up and metabolise citrate (known as Cit+). The citrate is in the medium to help the bacteria take up iron, but never normally enters the cell. Importantly E. coli can't eat citrate in aerobic conditions- its one of the defining characteristics of E.coli. (It seems there have been two other reports of Cit+ in E. coli and they've both come from swapping plasmids with other bacteria). The bacteria in the experiment lack plasmids, and only reproduce asexually. The scientists used their fossil record to investigate the process of Cit+ evolution, ruling out plasmids and contamination, and then tracking the process of Cit+ evolution. It seems there are at least 3 mutations involved, they didn't happen all at once, the earliest bacteria able to survive on citrate did so very poorly, and research remains to see what exactly is going on at the genetic level.
The paper is available online (pdf). You can also read abstracts and some pdfs from all the publications to come out of the LTEE.
The fact that one population is now significantly different from the others makes it very interesting to watch, because they've got a really visible, and important example of contingency. So lots to look forward to, and plenty more research to do. Carl Zimmer's been keeping a good blog on this, and Zachary was kind enough to turn up in the comments, offered to answer questions, and point people to other papers from the LTEE. Unfortunately a creationist turned up who didn't understand the meaning of the word "goal", so the whole thing turned into a car-crash. Zachary should have a guest post up there soon, dealing with some of the questions. (Excuse me I appear to be getting teary-eyed at a scientist engaging with the public- its so beautiful when it happens.)
Anyway, why did I mention Mr Schlafly? Well over at Conservapedia he wants Lenski to provide him with 20 years worth of data. He has it seems "skimmed" the paper and quoting PNAS's rules thinks he can demand this. Lenski politely points out that 1. the data is in the paper, and 2. he isn't saying what Schlafly thinks he's saying. This isn't enough for Schlafly, who complains that he must have access because they're taxpayer funded, and they sometimes say "data not shown". Lenski replies again, and I can't summarise it other than to say that Schlafly gets his arse handed to him on a plate. There are some beautiful quotes which I shall share, but you should read the exchange, at RationalWiki.
"If you have not even read the original paper, how do you have any basis of understanding from which to question, much less criticize, the data that are presented therein?"
"Am I or the reporter for NewScientist somehow responsible for the confusion that reflects your own laziness and apparent inability to distinguish between a scientific paper, a news article, and a confused summary posted by an acolyte on your own website?"
"But perhaps because you did not bother even to read our paper, or perhaps because you aren’t very bright, you seem not to understand that we have the actual, living bacteria that exhibit the properties reported in our paper, including both the ancestral strain used to start this long-term experiment and its evolved citrate-using descendants."
And for my American friends, an explanation of the differences between cricket and baseball. (It certainly explains why I understand cricket better than baseball.)
(Via Pharyngula, Bad Science, and pretty much everybody else by now.)