Saturday, August 27, 2016

Demons of the Deep

It is curious how so many life forms that grow in gradual and deliberate increments, live to such lengths. The tortoise with its fabled torpid movement, the century year old sea turtles, or the ancient Sequoia Redwoods. As with all trees that grow slower, they live longer, so there must be something to a slow growth rate. I suppose slow and steady does win the race.

My main question with this article however, is how do they really know the age of these sharks. The article seemed not to be speaking of any particular shark specimen they had found but rather, the species in general, as being the longest living vertebrae. It also seems an odd range of years to put the lifespan of the species at an exact 272 years. The article writes of the age-telling technique of measuring radioactive levels of carbon-14 in the eyes of the sharking (sounding like a complex and therefor accurate science), yet the range of possible age for the largest of the sharks collected in a 2010 study was between 272 and 512. That sounds laughably inaccurate, literally a range of 240 years. If I read this wrong I'd like to know but it seems to me they need to arrive at a more accurate technique.

This article, again brings me back to the unit on DNA (arguably the most interesting unit). I remember delving into the subject a little on my own when the question of aging came up and reading up on telomeres and just what they were. From what I remember, (and here's to hoping I don't butcher it) telomeres are structures at the end of our chromosomes that are like little protective caps. Each and every time our chromosomes replicate a little bit of those caps are worn off until our cells can no longer replicate like they used to. This means we can no longer heal and replace cells like our younger selves. Since every five years or so every last cell and atom of our body is replaced, replication is a constant and necessary process of life and without it we wither and lose functionality. This wearing-down of our telomeres is called senescence, but some creatures out there seem to exhibit no signs of senescence.The Immortal Jellyfish, the Rougheye Rockfish,. and even Crocodiles. A two century year old shark may sound intense but even more startling is the fact that crocodiles seem to have the potential to live for eternity. They show no signs of aging like other animals do and a seven year old Croc is as agile and fit as a 70 year old Croc. This is known as negligible senescence. Father Time cannot slay these ancient water demons, and they haven't changed one bit since the time of the Dinosaurs because they simply don't need too...they are already perfect, immortal, killing machines. Why you ask do we not see thousand year old Crocs? Because though time does not seem a factor in their demise, other Crocs can kill them, along with disease and starvation. Whats more terrifying is that with age, they keep growing. They grow bigger and stronger with each passing year and have the potential to live to pre-historic proportions. The only reason they don't is because to sustain their massive size, they need an equal supply of food. We see no "super-Crocs" because they simply cannot find sufficient food to match their necessary diet. Equivalent exchange.  Mother Nature, is the great equalizer.

Thursday, August 11, 2016

Cas9 - CRISPR than Toast

CRISPR-Cas9 just opened up a whole new can of tricks for the biological scientists of the world. Now we may very well possess the cure for cancer, and our own little pair of molecular scissors. I'm transported back to Bio and the NOVA documentary on the rascaleous scientists Watson and Crick and their discovery of the double helix, only so recently revealing the shape of our own DNA. That unit gave me, for the first time, an understanding of what DNA really was, what it was comprised of, and how all of its tiny components functioned as a molecular assembly line.

Now only 60 years later we have taken to reshaping that DNA. This article addresses probably the most noble cause we could think to put this science to use for, the crusade against cancer. But what interests me is all the myriad of uses our society will inevitably hunger for besides the noble medicinal cures. For this science is a game changer, a gene changer. Fundamentally DNA is the code of life, and at its core CRISPR is designed to change that code. CRISPR-Cas9 is at its most basic, a molecular scalpel (the enzyme Cas-9) armed with a targeting system (the RNA guide). Who decides what inputs are placed into that targeting system? After all, the possibilities expand far beyond cancer treatment. Any gene eligible for alteration is fair game, the gene that gives you those blue eyes the girls fall for, the curly hair that had all the neighborhood boys in a tizzy. Will our doctors and our scientists be left to decide what can and cannot be altered? Will our philosophers and pastors? Maybe even our politicians.

Now we truly can play God. When you go to the hospital to check up on your pregnancy with your spouse there will be a questionnaire with a list of desired traits for your child to have. Combine this with a gene drive and perhaps you could decide the genetic fate of your entire lineage. That is after all, what we do to animals already. See certain genes have higher chances of being inherited, but the gene drive overrides this to our choosing as we decide what gene shall be inherited, telling Lady Luck and Mother Nature to take the back seat. The AquaAdvantage Atlantic Salmon is a perfect example of this that is already in use, a breed of salmon that has been altered with CRISPR and the gene drive to engineer a fish twice the size of its natural counterpart, with less time and feed required. Now CRISPR already has a booth with its name on it in the food, cosmetic, and medical marketplace.

The cooperation of the gene drive even gives the possibility for biological resistances to be past down from generation to generation. If an altered gene granting resistance to certain diseases is placed in a host of mosquitoes the aim is to eventually spread resistance to the entire population, meaning no more Zika or Malaria. But it goes even beyond that because CRISPR has the potential to utterly rearrange the proteins and nucleotides that it encodes. Does this mean it will possess the ability to create entirely new genes?
With this advancement in technology we are faced with an ethical and moral dilemma of biblical proportions.
CRISPR is shaping up to be a tool with unending possibilities, a tool that may reshape the entire human genome.

The question is, how far will we go down the rabbit hole?