tag:blogger.com,1999:blog-37148773.post7189934608342230816..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Extending evolutionary theory? - Tobias UllerLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-37148773.post-62465499556595031212016-09-30T21:10:10.270-04:002016-09-30T21:10:10.270-04:00I like "so-called" the best. Anyone else...I like "so-called" the best. Anyone else?John Harshmanhttps://www.blogger.com/profile/04478895397136729867noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-88702035117407285112016-09-30T19:30:16.730-04:002016-09-30T19:30:16.730-04:00@Larry, are you implying that heritable epigenetic...<i>@Larry, are you implying that heritable epigenetic changes aren't "heredity"? As far as I can see, they are, though the inheritance is very imperfect.</i><br /><br />It depends on how you define "heridity." In the case of methylation let's review what we know about restriction/modification in bacteria. When the cell divides, the daughter cells each receive a single strand of DNA from the parent and that DNA will be methylated. The newly replicated strand will not be methylated so the site won't protect against restriction endonucleases. However, the methylase enzyme in the daughter cell will recognize the hemimethylated site and add a methyl group to the other stand. Thus the site will become protected.<br /><br />I'm happy to count this as heritable but I don't think we need to revise evolutionary theory because of it. Restriction/modification was worked out in the 1970s and I don't recall any clamor for changes in evolutionary theory. <br /><br />The situation with respect to modified histones is much more complicated. There are no histones on sperm DNA so the zygote can't inherit such modifications from males. The modified histones may be passed from the female to the zygote if they survive meiosis and if the female germ cell had the appropriate markers in the first place. Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-54096981374937674982016-09-30T16:42:10.695-04:002016-09-30T16:42:10.695-04:00Welcome to the world of epigenetics Joe!
I had t...Welcome to the world of epigenetics Joe! <br /><br />I had thought you'd never make it. Well, I guess I'm getting old or naive...<br /><br />I hear that Harshman and Mitzke are making a come back too but Nick reluctantly though...<br /><br />Can you explain a bit further what "kind of heredity means please?Jmachttps://www.blogger.com/profile/04392421995310271733noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44818919864473570902016-09-30T16:36:05.360-04:002016-09-30T16:36:05.360-04:00I feel your pain now though not to mention the fut...I feel your pain now though not to mention the future one Jerry. Sticking to your only gun-natural selection as the main mechanism of evolution isn't going to get you much support now and in the future, even from Larry. <br /><br />Since you have retired from your so-called scientific work, I think the time has also come to retire the 150 year old myth of natural selection as being the driving force behind evolution, don't you think Jerry?Jmachttps://www.blogger.com/profile/04392421995310271733noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-47129670121297510412016-09-30T16:35:49.156-04:002016-09-30T16:35:49.156-04:00@Larry, are you implying that heritable epigenetic...@Larry, are you implying that heritable epigenetic changes aren't "heredity"? As far as I can see, they are, though the inheritance is very imperfect.<br /><br />And "plasticity" describes the way a given genotype responds to environments in causing a phenotype. The plastic response itself is not inherited. It puzzles me why "plasticity and epigenetics" are alternatives to "heredity". The former is not inherited, except in that genotypes that are differently plastic get inherited. The latter is a kind of heredity.Joe Felsensteinhttps://www.blogger.com/profile/06359126552631140000noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-2619297355009494762016-09-30T12:57:47.697-04:002016-09-30T12:57:47.697-04:00Development is an outcome of heredity. This has a...Development is an outcome of heredity. This has already been well established.<br /><br />If I were in a smart ass mood I might ask Dr. Uller what environmental conditions would cause a human to give birth to a cat.Erichttps://www.blogger.com/profile/09481645265615126897noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-21654258009724203182016-09-30T12:07:27.209-04:002016-09-30T12:07:27.209-04:00Larry, I feel your future pain. As for that abstra...Larry, I feel your future pain. As for that abstract, I have no idea what the guy means. Anonymousnoreply@blogger.com