{"id":2735,"date":"2008-06-13T13:21:13","date_gmt":"2008-06-13T13:21:13","guid":{"rendered":"http:\/\/scienceblogs.com\/gregladen\/2008\/06\/13\/the-origin-of-life-on-earth-ne\/"},"modified":"2008-06-13T13:21:13","modified_gmt":"2008-06-13T13:21:13","slug":"the-origin-of-life-on-earth-ne","status":"publish","type":"post","link":"https:\/\/gregladen.com\/blog\/2008\/06\/13\/the-origin-of-life-on-earth-ne\/","title":{"rendered":"The Origin of Life on Earth: New Research"},"content":{"rendered":"

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A very Darwin-like god ponders what the nature of life will be like. From Monty Python’s The Meaning of Life. <\/em> <\/center><\/span>The origin of life presents a number of fundamental difficulties to science. One of these is the seemingly irreducible complexity of life itself. For instance, DNA codes for the molecules that are essential to life. Some of these molecules, however, are the very enzymes that help DNA code for molecules. It is difficult to imagine DNA works without these enzymes, but the enzymes exist in a cell because, in part, of the activities of DNA. Even the basic process of moving molecules into cells to use in the construction of DNA or other molecules requires molecules that are thusly constructed.What’s an evolutionary biologist to do????Well, we can start with research, such as modeling ancient systems, looking for clues about the nature of the ancient environments in which life may have originated.\"ResearchBlogging.org\"<\/a><\/span>With respect to early life, most of this research assumes that some kind of “proto cell” or cell-like environment existed allowing a subset of the known biological processes to happen. In this view, we start with existing life and take away parts, working backwards to simpler forms, occasionally substituting one kind of system with a different kind of system. For instance, some models of early life have geology providing cell membranes; Bubbles in certain kind of rock, or the space between layers of mica serve as cell-like spaces.I think there are problems with this approach, but this is a start.A new paper in Nature<\/em> addresses one of the problems with early life, specifically, the way important molecules can be transported across a membrane-like protective boundary. In addition, these researchers have made a contribution to the question of replication of DNA-like molecules in early life or protolife.Living cell membranes are made up of phospholipids. Phospholipid “heads” are hydrophilic (attracted to water), but the tails are hydrophobic (they are “afraid of” water). So, a bunch of phospholipid cells floating around in water tend to arrange themselves into a two-layered configuration with the heads pointing outwards. This mass of molecules forms a membrane impermeable to nutrients or nucleotides. So while the naturally arranged phosophlids form a nice barrier, they do not serve the role of selectively transporting molecules into or out of a cell.However, some fatty molecules have more complex structures, so when they are included in a membrane, the result is a surface that has room for the passive movement of certain biologically important molecules. The researchers managed to construct such a membrane, and thus created a sort of “protocell” made out of fatty acids likely to have been present on Earth during the early evolution of life.When single stranded DNA is encapsulated inside of such a membrane and the appropriate molecules are in the environment, these molecules manage to end up inside the protocell and, using the template, replicate the original DNA.This is not quite enough to fully explain how cells got started, but it is a significant advance in this area of research.<\/span>Mansy, S.S., Schrum, J.P., Krishnamurthy, M., Tob\u00c3?\u00c2\u00a9, S., Treco, D.A., Szostak, J.W. (2008). Template-directed synthesis of a genetic polymer in a model protocell. Nature DOI: 10.1038\/nature07018<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

A very Darwin-like god ponders what the nature of life will be like. From Monty Python’s The Meaning of Life. The origin of life presents a number of fundamental difficulties to science. One of these is the seemingly irreducible complexity of life itself. For instance, DNA codes for the molecules that are essential to life. … Continue reading The Origin of Life on Earth: New Research<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"1","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[247,151,162],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p5fhV1-I7","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/posts\/2735"}],"collection":[{"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/comments?post=2735"}],"version-history":[{"count":0,"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/posts\/2735\/revisions"}],"wp:attachment":[{"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/media?parent=2735"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/categories?post=2735"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gregladen.com\/blog\/wp-json\/wp\/v2\/tags?post=2735"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}