tag:blogger.com,1999:blog-37148773.post7375181284020402744..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Repression of the lac OperonLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-37148773.post-45086417049133522622012-12-13T03:49:37.823-05:002012-12-13T03:49:37.823-05:00Very good explanation ,my background is synthetic ...Very good explanation ,my background is synthetic chemistry but I clearly understand this topic Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-15807406447090223462012-10-20T20:18:11.959-04:002012-10-20T20:18:11.959-04:00I have a question, I am a junior in high school an...I have a question, I am a junior in high school and I am hoping someone can answer this for me. We were talking about the Lac Operon in my AP Biology class the other day and I learned that it is in the E. coli genome, not in the human genome, so how does lactose intolerance work? Couldn't you-in theory- just drink butter milk- which contains E. coli- to get new E.coli in your gut. Because the chances of ever strain of E.coli a single person comes in contact with being defective is pratically impossible. It can't be your body rejecting the E.coli because then you would have diarreha, because E.coli controls our water absortion. It can't be your body attacking the lactase (which is an enzyme, and enzymes are a protein) because that is an allergy and would express its-self in anaphalixis (hives, swelling, vomiting etc.) So, what exactly is it? Does it have to do with the production allactose (which binds with the represser to make the represser inactive and start the production of lactase)?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44371605017608509282008-02-21T04:58:00.000-05:002008-02-21T04:58:00.000-05:00anonymous says,This value is going to be known wit...anonymous says,<BR/><BR/><I>This value is going to be known with a lot more certainty in just the immediate future.</I><BR/><BR/>Dream on. If history is any judge, what we're going to see is exaggerated claims about enormous amounts of functional RNA. It will probably take about ten years for scientists to realize that those claims are bogus and make no sense in terms of basic biochemistry and fundamentals of evolution.<BR/><BR/>I fear we are entering the dark ages of science where wishful thinking and superstition trump serious intellectual activity.<BR/><BR/>These days, critical thought seems to be something that one avoids at all costs.Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-72103696578280147932008-02-20T17:20:00.000-05:002008-02-20T17:20:00.000-05:00...the assumption should be that a transcript has ...<I> ...the assumption should be that a transcript has no function unless proven otherwise. </I><BR/><BR/>Papers like that of Wu et al. mean you don't need to make this assumption -- you can look at the actual data. A more meaningful question is, what fraction of these previously uncharacterized transcripts have some kind biological function. It would appear from this work that 10% is a reasonable, conservative answer, but again, this is an experimentally testable figure. The ENCODE project has clearly provided the motivation to actually do these kinds of studies. This value is going to be known with a lot more certainty in just the immediate future.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44489486238744188552008-02-20T10:47:00.000-05:002008-02-20T10:47:00.000-05:00I've just read that Genome Biology paper and it's ...I've just read that Genome Biology paper and it's entirely consistent with Larry's points.<BR/><BR/>The key point, surely, is that knowing what we do about the biochemistry of transcription, the assumption should be that a transcript has no function unless proven otherwise. Anon, what's your justification for assuming the opposite?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-29812393422863174552008-02-14T09:09:00.000-05:002008-02-14T09:09:00.000-05:00Confidence is not a very convincing substitute for...Confidence is not a very convincing substitute for actual data. You know how science works... if you want to make a statement of fact, show the data, or give the reference.<BR/><BR/>Papers like this one:<BR/><BR/>Wu JQ, Du J, Rozowsky J, Zhang Z, Urban AE, Euskirchen G, Weissman S, Gerstein M, Snyder M.<BR/><B>Systematic analysis of transcribed loci in ENCODE regions using RACE sequencing reveals extensive transcription in the human genome.</B><BR/>Genome Biol. 2008 Jan 3;9(1):R3 <BR/>http://genomebiology.com/2008/9/1/R3<BR/><BR/>make me considerably less sure of your conclusions. Speaking for myself only, I think the acquisition of more data is needed on this topic before the issue can be considered settled, although clearly your mileage may vary.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-38806789191611729912008-02-14T04:14:00.000-05:002008-02-14T04:14:00.000-05:00anonymous says,But of course, you have no way of k...anonymous says,<BR/><BR/><I>But of course, you have no way of knowing this.</I><BR/><BR/>Of course I do. That's the whole point. I may not be able to indentify whether a <B>particular</B> transcript is functional or not but a thorough understanding of biochemisty theory enables me to say with confidence that most rare transcripts will not have a biological function. <BR/><BR/>Unfortunately, there are too many so-called scientists out there who don't understand the basic concepts so it's easy for them to get confused.<BR/><BR/>I don't think we're doing a good job of teaching the principles and concepts.Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-21881530367753722172008-02-13T14:19:00.000-05:002008-02-13T14:19:00.000-05:00These transcripts are merely a consequence of the ...<I>These transcripts are merely a consequence of the properties of DNA binding proteins and they have no biological significance.</I><BR/><BR/>But of course, you have no way of knowing this.Anonymousnoreply@blogger.com