Two weeks in a row; you mammalian malcontents are killing me. My date from last week, the dashing barn owl, took one sniff of me and flew away, hooting about raw sewage and rotting mouse entrails. You only get one shot with a barn owl.
Anyway, I have cleared my social calendar for the next few days, and have hired a team of hazardous materials specialists to scrub this place top to bottom following your departure, so we are free to continue. I beg of you though, please don’t think of my preparedness as an invitation to act like, well, a group of humans. Before you do anything, ask yourself this simple question: “what would an owl do?”
(Although that line of reasoning assumes you ghastly beasts have something approaching an internal monologue, and we know that is most certainly not the case.)
Now, back to the cloning.
So, we have talked about where to get the DNA, how to get the DNA, what DNA is and even how to copy DNA. While I’m sure that most of you don’t even remember what I said five minutes ago, let alone five weeks ago, I’m going to continue moving forward regardless of your comprehension.
Today’s talk will focus on the sequencing of the DNA. Need me to spell that for you? I’ll write it on the chalkboard here . . . there you go, “sequencing,” meaning to read the genetic code contained within your DNA.
Now, even you simple evolutionary disappointments have well over 3 billion base pairs — remember, the adenosine, thymine, cytosine and guanine bases we talked about last week — in your genetic code, and reading, let alone sequencing, that many base pairs would take a human millennia.
Interesting aside: despite your claims to the contrary, your genome has about the same number of base pairs as a mouse. I knew there was a reason why you both make excellent entrées.
Thankfully, someone named Alan Turing — who was no doubt an owl/human hybrid sent back from the future — invented the digital computer almost 50 years ago. With the advent of the computer, we can do something called shotgun sequencing, where random segments of DNA are read all at once.
Once the computer has read all the sequences in a segment of DNA it looks for overlapping regions, and assembles a complete strand.
“How does the computer read the segments?” you might ask, were your species granted the neural fortitude to ask a question, let alone form complete sentences. Well, it’s really quite simple. The DNA is denatured and a series of fluorescently tagged adenosine, tyrosine, cytosine and guanine bases are added to the mix. They bind to the vacant spots on the single stranded DNA, which can then be read with the computer that can correspond a specific wavelength of light to a specific base.
Once you have the sequence you can then make changes to those sequences, but that is a topic for another day.
Now away with you, before it gets too dark. I shudder at the thought of one of you getting lost in the dark and needing to, oh how does your species put it . . . “crash” in my lair.