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May 29, 2012 | Posted By David Lemberg, M.S., D.C.

Genesis 1:26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.

April 2012 brought news of the latest shot fired over the bow of genetic inheritance as we know it. Ever since the discovery of the structure of DNA by Watson and Crick in 1953 and the subsequent elucidation of the triplet nature of the genetic code by Marshall Nirenberg and others in the early 1960s, many scientists have fantasized about obtaining mastery over this primordial biomolecule.

An interim pinnacle of achievement in this hopeful process would be to create a DNA-like molecule whose information content would be both heritable and evolvable. Synthetic Genetic Polymers Capable of Heredity and Evolution presents elegant work along this path which may signal a substantive shift in humankind’s ability to manipulate the language of life.

Holliger et al. report on their activities in building an XNA (xeno-nucleic acid) which fulfills the criteria of heritability and evolvability. The authors blithely state they have demonstrated information storage and retrieval in six alternative genetic polymers not found in nature. The ramifications of the phrases “alternative genetic polymer” and “not found in nature” are many and profound. The weight of this investigative stone flung into the deep pool of evolutionary time may create unceasing ripples for millennia or more.

The work itself involved engineering polymerases that could synthesize XNA from a DNA template and reverse transcriptases that could read XNA and turn that information back into DNA. Then, the researchers explored “the capacity of such genetic polymers for Darwinian evolution”. A mere eight rounds of selection yielded the sought-for consensus motif.

In terms of pure knowledge acquisition, the importance of this work cannot be overstated. Similarly, the ethical and moral issues raised are thorny and complex. The primary question may be posed simply: “Is it right to do this?” Holliger et al certainly have demonstrated the ability and the capability of creating a novel heritable and evolvable information-bearing molecule akin to DNA. But it is owing to DNA (considering human ontology merely from a physical point of origin) that we are here at all. Humans specifically did not evolve from either threose-based (TNA) or anhydrohexitol-based (HNA) biomolecules [nucleic acids utilizing alternative ribose backbones; the ribose in DNA is deoxyribose].

DNA is the information storage-and-retrieval system for almost all life on our planet. There must be a deep reason for this, one hidden from view by the countless strata of departed eons. Even if our perspective does not include Creation, we can posit a prolonged exploration of the early evolutionary fitness space that concluded with DNA and RNA. Other nucleic acid variants were excluded. Whatever they were, whatever their configuration, they failed the test. To revivify “alternative genetic polymers”, just because we can, may not be a good idea, neither in the short-term nor the long-term.

The Alden March Bioethics Institute offers graduate online masters in bioethics programs. For more information on the AMBI master of bioethics online program, please visit the AMBI site.

0 comments | Topics: Bioethics and Public Policy, Bioethics in the Media, Genetics, Health Care Policy, Philosophy


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BIOETHICS TODAY is the blog of the Alden March Bioethics Institute, presenting topical and timely commentary on issues, trends, and breaking news in the broad arena of bioethics. BIOETHICS TODAY presents interviews, opinion pieces, and ongoing articles on health care policy, end-of-life decision making, emerging issues in genetics and genomics, procreative liberty and reproductive health, ethics in clinical trials, medicine and the media, distributive justice and health care delivery in developing nations, and the intersection of environmental conservation and bioethics.
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