23 Skiidoo

23 Skiidoo

Just what are chromosomes? You hear about them all the time these days, in the media and the internet. Are those 23 wiggly strips of DNA that cursed you through high school biology class exams even worth your time when groceries, soccer, kids, work, traffic, and family all take a piece of you already?

glow-dnaGenetic engineering is arguably the most significant single tool humans possess to change their future. It affects everything you can think of. Eradicating viruses, eliminating bacterial resistance, stopping birth defects, cleaning up polluted water, increasing crop yields, all on the radar in the genomic future of humans. I’d like to elaborate on each of those, but suffice to say the essay would become a text book.

I’m only thinking of the human condition for this little blog. Let’s take a look at just a couple chromosomes so the task is manageable. By the way, I want to plant an image in your mind of the correct direction of a helix. As you look at the right side of the drawing, the bands in the fore of the diagram should be as this diagram displays, from the right downward. Why? Because a molecule of DNA is a chiral molecule, and on Earth at least, amino acids twist to the right (most sugars, however, twist to the left, chirally speaking. This is an entirely separate subject). Take my word for it or you can go see a detailed explanation here.

So back to chromosomes. Note that the letter N is not part of the word chromosome, I just want to draw your attention to that if you need to write the word and your spell checker is asleep. A chromosome, of which we have 23 pairs, is a really, really, long, long, long, complex molecule of nucleic acids, perhaps two meters long in some cases, all curled up tight and folded over itself countless times. Some of these chromosomes have as many as 5000 base pairs, those little bars that cross from one side to the other. So let that sink in. A two meter strand of microscopic nucleic acids, thousands of them, all compressed so small that 46 of them fit inside the nucleus of a single cell. Tiny is an understatement. I’m not sure I can think of an appropriate word other than microscopic or quantum to impress upon the eency weenciness and complexity of such structures. Suffice to say, they’re really small.

what-is-down-syndrome1Genetic engineers have found a way to reduce the severity of mental retardation in children with an extra chromosome 21 (Down’s syndrome) if they are aware of the mutation and can intervene before 10 weeks when the neural pathways begin to develop. New technology allows doctors to use fragments of fetal DNA found in the mother’s blood to diagnose the condition so an amniocentesis or CVS doesn’t have to be performed (increasing chance of miscarriage), which by the way is performed too late to correct the issue. Although heart development and characteristic features are already set, the mental retardation that accompanies Down’s Syndrome can be significantly reduced offering these children a more traditional future of independence and community acceptance.

We should respect nature, but not fear our ability to reduce suffering and lifelong disabilities if the technology supports intervention. We also will find that we must define what is a disability and to what degree. Is total blindness a given fix but nearsightedness on the fence? How much of a disability is really a disability? Will gene manipulation one day be used in the everyday care of pregnancy that an engineer can fix incurable disorders or will the simply undesirable disorders also be up for grabs? As we wade into the shallow waters of the primordial gene pool, we should be excited, responsible, and consider as many angles as possible before we go over The Cliff of No Return.

2 Replies to “23 Skiidoo”

  1. I hate to disillusion you but Chromosomes are long double helix strands of DNA or deoxyribose nucleic acids. They encode the genome and gene instruction set o synthesize amino acids and proteins, but there are many anabolic steps of RNA i.e. mRNA,tRNA,rRNA and subsets of these i.e. miRNa,siRNA,shRNA,etc. I agree with you respect for nature and her 3.0+ billions years of evolutionary change, growth and adaptation in the form of new cell types, species and other carbon based life forms. The air must have very little oxygen in the Stratosphere since the substitution of amino acids for nucleic acids as the encoding and decoding molecules is one of the most basic concepts in genomics and even elementary biology. Shame on you for espousing scientific ignorance. Makes the rest of your commentary rather specious.

    On Tue, Nov 1, 2016 at 12:45 PM, From The Stratosphere wrote:

    > hsrivney posted: “Just what are chromosomes? You hear about them all the > time these days, in the media and the internet. Are those 23 wiggly strips > of protein that cursed you through high school biology class exams even > worth your time when groceries, soccer, kids, work, t” >

    1. You’re obviously educated beyond the average bear in this field. I’m sorry to have offended you so that you feel you are entitled to shame me for my errors. I will employ the flog and mercilessly beat myself senseless and throw myself in the beautiful gene pool at Caltech. Linus Pauling would appreciate your point of view. Since my blog post was not a scientific white paper, nor am I teaching a class in genomics or elemental biology, I hope you can forgive me for such an egregious error. Guanine, Cysteine, Thiamine, and Adenine are of course nitrogen bases, and I should have been much more succinct in describing how DNA is not really a strand of protein/amino acids. I should have said that a group of three of those bases code for an amino acid (one of 20) and that amino acids make up proteins. I took a short cut because my audience is not generally made up of anyone who actually cares about the sugar phosphate backbone or even if I’m talking about a prion or a virus. I’m looking to engage readers in a dialect they can understand so as to get a couple of them interested in scientific topics and consider researching further on their own without putting them totally to sleep mid-sentence. I don’t want to sound condescending to my readers using the scientific jargon of a PhD. On another note, it’s nice to know I’m reaching a larger audience than I anticipated, including enlightened readers such as yourself, perhaps even Juan Erinquez himself. I promise I will correct my shameful and specious blog to ensure I haven’t mislead anyone who might be studying for the MCAT or trying to write a science fiction novel.

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