<story><title>Our closest worm kin regrow body parts, raising hopes of regeneration in humans</title><url>http://www.washington.edu/news/2016/11/28/our-closest-worm-kin-regrow-body-parts-raising-hopes-of-regeneration-in-humans/</url></story><parent_chain><item><author>PeterisP</author><text>Well, a plausible answer is that if we (or random mutations) re-enable those genes then the end result is simply a lot of cancer.&lt;p&gt;A reasonable default assumption is that each switch in our &amp;quot;genetic configuration&amp;quot; is set to a quite good value.&lt;p&gt;The only exception is if we see a feature that is beneficial at a high calorie cost - those features have been (reasonably) optimized away during our evolution, but would be useful in modern circumstances where food is not scarce anymore; this is a tradeoff where it would make sense to just turn the dial way to the right from where it had been throughout the last million years.</text></item></parent_chain><comment><author>JonathonW</author><text>&amp;gt; A reasonable default assumption is that each switch in our &amp;quot;genetic configuration&amp;quot; is set to a quite good value.&lt;p&gt;I&amp;#x27;d question that assumption--  each switch in our &amp;quot;genetic configuration&amp;quot; is set to &lt;i&gt;a&lt;/i&gt; value, and it&amp;#x27;s set to one that results in survival often enough for the species to reproduce, but it&amp;#x27;s not necessarily the optimal value, or even a particularly good one.  It&amp;#x27;s just one that happened to be able to survive under environmental pressures at some particular time.&lt;p&gt;To put this into a computer science context, genetic algorithms have the same problem--  they can find local maxima easily, but can have difficulty (depending on the nature of the search space) locating global maxima because they can&amp;#x27;t sacrifice short-term fitness to gain long-term fitness.</text></comment>
<story><title>Our closest worm kin regrow body parts, raising hopes of regeneration in humans</title><url>http://www.washington.edu/news/2016/11/28/our-closest-worm-kin-regrow-body-parts-raising-hopes-of-regeneration-in-humans/</url></story><parent_chain><item><author>PeterisP</author><text>Well, a plausible answer is that if we (or random mutations) re-enable those genes then the end result is simply a lot of cancer.&lt;p&gt;A reasonable default assumption is that each switch in our &amp;quot;genetic configuration&amp;quot; is set to a quite good value.&lt;p&gt;The only exception is if we see a feature that is beneficial at a high calorie cost - those features have been (reasonably) optimized away during our evolution, but would be useful in modern circumstances where food is not scarce anymore; this is a tradeoff where it would make sense to just turn the dial way to the right from where it had been throughout the last million years.</text></item></parent_chain><comment><author>ryandvm</author><text>The ability to regenerate body parts and cancer are not inextricably linked. Take the axolotl. It has the ability to regenerate entire limbs. It&amp;#x27;s also estimated to be a couple orders of magnitude more resistant to cancer than humans.</text></comment>