Life- but not as we know it

It is now 50 years or so since the genetic basis for life was discovered. This was the now famous Watson and Crick discovery of DNA. Essentially DNA is a sort of blueprint for life coded  in 3 billion characters in such a way that it can reproduce itself. The DNA is known to eg. code for specific proteins which form the building blocks of living cells. Every cell contains a copy of the DNA of the organism.

There have long been relatively crude ways of modifying DNA. However a much more precise method is now available which rejoices in the acronym CRISPR. This is a popular way to naming the technique which offers a exact way of inserting or deleting DNA codes.

It appears to be conceptually possibly to synthesise DNA although the main use is to modify DNA to remove parts known to cause problems. Even this is sometimes controversial. It is possible for example to modify part of the male contribution to DNA in such a way that not only is the baby saved from the defect but all subsequent children of that baby are also saved.

Current projects to synthesise DNA have far less dramatic objectives. One such ( called Sc2.0 ) aims to recreate the genome of brewer’s yeast. Compared with a human genome this is relatively simple as only some 12 million coding units are involved as against the 3 billion in a human genome. The objective is to understand more fully how the yeast works and ultimately to improve it. The work is ongoing with 2018 set for its early objectives.

Rather differently  a US group claims to have made the DNA of a simple bacterium and then whittled it down to the absolute minimum necessary for the bacterium to live. However the team finds that some 32% of the code is not understood; essential to life but of unknown function.

Far more ambitious is a proposal for what is called the Human Genome-Write project ( HGW ). The idea is to develop technology to enable DNA code to be written.  This is at present a proposal seeking funding, and it will be vastly expensive. To read the human genome required some $3 billion and although subsequent advances in technology have much reduced this sum. HGW would have, certainly initially, some limited objectives. One objective is modify the pig genome so its organs are more suitable for human transplants. There is a huge shortage of organs for human transplants and pig organs are reckoned to be the best possibility for improving organ supply.

Popular science journals have made melodramatic noises about a synthetic human. This looks a million miles away even if HGW goes ahead. Bioethicists are already commenting which seems decidedly premature.

Scientific progress moves in waves and it seems that while physics is making slow progress building on insights now a century old,  biology is making rapid strides based on developments in DNA technology.