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Friday, June 06, 2003

Creature Feature #2: Hamish the Highland Bull

Ok, I'll admit up front that I know nothing about cows and am not usually a big cow "fan". Regardless, this is an amazing cow. He's a ten year old Highland bull named Hamish living in Kilmahog, Scotland. My friends Andy and Joanna report that for 30 cents you can purchase vegetables and feed him. They say he's very sweet, but they recommend to watch out for the horns. I feel oddly compelled to buy a plane ticket.

Tuesday, June 03, 2003

Gecko tape

Wow! Nanotechnology has given us a new form of adhesive tape based on the same trick that makes gecko feet sticky (ScienceNOW 02 June 2003, but you need a subscription). The tape was developed by material scientists at the University of Manchester is covered with tiny, flexible plastic hairs. Supposedly its stronger than duct tape AND reusable! I am so impressed.

Common sense prevails

Another reasonable reaction to the genetic enhancement debate: MIT prof Stephen Pinker provides sound reasons why human genetic enhancement is nothing to worry about. His main argument is that the technology is just not likely to work, at least any time in the foreseeable future. As mentioned before, there is the problem that most traits are controlled by multiple genes. However, Pinker also brings up the equally important point that most genes have multiple functions.

It gets worse. Most genes have multiple effects, and evolution selects those genes that achieve the best compromise between positive and negative impacts. Take the most famous case of genetic enhancement on record: the mice that were given extra copies of the NMDA receptor, which is critical to learning and memory. These poster mice did learn mazes more quickly-but they also turned out to be hypersensitive to pain. Closer to home, there is a gene in humans that may be correlated with a 10-point boost in IQ. But it is also associated with a 10-percent chance of developing torsion dystonia, which can confine the sufferer to a wheelchair with uncontrollable muscle spasms.

The biology that underlies this point is quite interesting. The ability of a single gene to affect both intelligence and muscle function seems mysterious if one relies on the popular conception of genes as traits. In fact, its probably more instructive to think of genes as the tools that are used to build the traits. In that case, genetic engineering is similar to changing the tools in one's toolbox. If you remove the hammer from your tool kit and replace it with a pneumatic chisel, you're psyched when you need to cut granite but out of luck when it comes to hanging pictures.

The real trick to making it all work is the blueprint, the regulatory DNA, that provides instructions for when to use each tool and where. And, unfortunately, rather than being written out in separate imperatives like "Put the picture window here. Put the door here. Staircase goes here, etc." its written in a sort of recursive code so that changing one set of instructions can affect more than one building process. This is not to say that its impossible to figure out how genes are regulated. We already understand some of the basic instructions, and with the sequencing of the human genome we are going to have a much better appreciation of the overall design process. However, this is a far cry from being able to add in instructions that selectively affect one trait.

That said, the genetic code is an extremely flexible design tool that can be used to create elaborate structures without compromising the ability to reproduce. On an intuitive level though, its seems there must be compromises and constraints on the design of an organism that are inerent to the design tool itself, rather than to extrinsic physical forces (e.g., gravity, oxygen content of the air). Interesting to think about what sort of compromises are made when creating little projecting gizmos, big ears, bright colors, fuzzy hair....

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