tag:blogger.com,1999:blog-37148773.post3981143530639107447..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: The Trichoplax GenomeLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-37148773.post-69264726937676421642009-01-26T09:04:00.000-05:002009-01-26T09:04:00.000-05:00where can one get a copy of the video-clip on Tric...where can one get a copy of the video-clip on Trichoplax adhaerens for teaching purposes?<BR/>Please reply to jco@helmholtz-hzi.de<BR/><BR/>Very nice article <BR/>John CollinsJohnCollinshttps://www.blogger.com/profile/13542501033336861705noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-8311523853253715242008-08-28T05:57:00.000-04:002008-08-28T05:57:00.000-04:00I saw this on an ID website:http://www.thedesignma...I saw this on an ID website:<BR/><BR/>http://www.thedesignmatrix.com/content/another-phylum-supports-front-loading/<BR/><BR/>Could someone do a review of this website?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-53989275189341711552008-08-27T14:32:00.000-04:002008-08-27T14:32:00.000-04:00frank says,It's a good post but has one flaw. The ...frank says,<BR/><BR/><I>It's a good post but has one flaw. The assumption "coding sequence = gene" is quite wrong.</I><BR/><BR/>I have never made that assumption as anyone who reads my opinions on genes and genomes would know.<BR/><BR/><I>If a gene is the sequence responsible for a heritable trait, then there are a large number of RNAi genes that we know little about. Several, for example, are involved in malignancy, and that certainly is a heritable trait.</I><BR/><BR/>I'm well aware of the existence of genes whose product is RNA. Been teaching that for over thirty years. We've known about small regulatory RNAs for almost as long.<BR/><BR/>The question is not whether genes for small regulatory RNAs exist, it's whether there are a lot of them. I don't think there are lots of them, certainly not enough to make a significant difference in the number of genes.Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-32572593721944168332008-08-27T12:28:00.000-04:002008-08-27T12:28:00.000-04:00It's a good post but has one flaw. The assumption ...It's a good post but has one flaw. The assumption "coding sequence = gene" is quite wrong. If a gene is the sequence responsible for a heritable trait, then there are a large number of RNAi genes that we know little about. Several, for example, are involved in malignancy, and that certainly is a heritable trait.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71830820638567671652008-08-26T23:33:00.000-04:002008-08-26T23:33:00.000-04:00Hexactinlellid (silicatous)sponges, THOSE are the ...Hexactinlellid (silicatous)sponges, THOSE are the ones missing, crucial to this case (their spicules are the oldest in the fossil record)<BR/><BR/>Despite the shortcomings of taxon sampling the genome-wide comparisons results are still a good possibility according to morphology and have basically confirming the morphologically most parsimonious assumption, that Placozoa are basal metazoa. Those aspects will for sure be maintained when taxon sampling is improved. <BR/><BR/>The more specific questions may still find new answers with better data.<BR/><BR/>BTW, of course, some sponges DO have fibrilar contractile cells; Actually the actin-myosin contractile apparatus is a pre-metacellular innovation.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-17557364273984180592008-08-26T20:58:00.000-04:002008-08-26T20:58:00.000-04:00"The result are not compatible with trees construc..."The result are not compatible with trees constructed using mitochondrial sequences or ribosomal RNA sequences but that's not too surprising. Mitochondrial DNA and ribosomal RNA sequences are often not reliable for this kind of work"<BR/><BR/>I'd say that definitely there were morphological reasons to consider this basal, but otherwise there wasn't much morphological reason for a particular affinity to the eumetazoa. They could be the mos basal metazoa; also, the possiblity that placozoans are simplified sponges is not discarded by this new data, since porifera may be paraphyletic, including the clade placozoa+eumetazoa.<BR/><BR/>Even genome wide-comparisons are likely to change if the taxon sampling is poor. Including intermediate forms can (and will!) change the structure of the tree.<BR/><BR/>In this sense I commend the work for having included a choanoflagellate, but that's about it. The calcisponges are not there: only a demosponge. The deuterostome is..."human"! The protostomes are a snail and fruitfly, and both cnidarians are anthozoans (as far as I know). The ctenophores, as usual, are the elephant in the room: they usually have this thing: in molecular studies, they POOF! DISAPPEAR!!! <BR/><BR/>There is no evident morphological signal. Placozoa are similar to some poriferan and cnidarian larvae, simpler if anything. It is usually the case that mithochondrial and ribosomal genes have better taxon sampling. I would take genes that have a good taxonomic sampling more seriously. We'll see what happens: There is still much "bizarre that needs sequencing!!!!A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-53674651462017623632008-08-26T20:46:00.000-04:002008-08-26T20:46:00.000-04:00This comment has been removed by the author.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.com