Half Bananas

What’s the difference between a human and a banana?

Not as much as you might think.

If you were to compare the DNA structure of a human with that of a banana, you’d find that 50% of it would be identical. Ergo, you could conceivably say we’re all half bananas.

But how does that work?

Warning: the following section has the gall to contain actual science, plus some fun facts about DNA. If your DNA influenced tendencies are telling you to run screaming in panic, you might want to skip forward to the more social stuff.

DNA Basics (Because that’s all I can understand)

• DNA = Deoxyribonucleic Acid
• Every living thing contains DNA; it is the instruction book for what makes a human a human or a banana a banana.
• DNA is structured like a ladder that’s been given a twist, which is why it is sometimes called a double helix. (A single helix would be like the railing of a spiral staircase.)
• Each rung of the ladder is made of a chemical base pair. There are only four types of bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
  • Adenine (A) only pairs up with thymine (T), and guanine (G) only pairs with cytosine (C). This is important for replication.
• A vertical side piece, or backbone for one side of the ladder is made of a sugar molecule, one of the bases, and a phosphate molecule. This component is called a nucleotide, and the nucleotides attach together to make a strand, shaped like a single helix.
• Because of the pairing limitation noted earlier, if you have a strand for one side of the ladder, you can automatically assemble the complementary strand for the other side, ending up with a double helix. That’s why DNA replication works, and cell division is possible. The double helix unzips, each side bonds to its complement components, and you end up with two copies.
• The ordering of the bases in a strand of DNA is the code that defines an organism. For a human, there are about three billion base letters in that sequence.
• Sections of DNA that code for proteins are called genes. The complete set of genetic information for an organism is called the genome. The latest estimate is that there are between 20,000 and 25,000 genes in the human genome.  The size of a gene may vary greatly, ranging from about 1,000 bases to 1 million bases in humans.
• Genes only make up about 1 percent of the human DNA sequence. DNA outside the 1 percent are involved in regulating when, how and how much of a protein is made. Presumably, that’s how cells know how, when, and where to make a nose, a kidney, or a banana peel despite having the whole DNA code available.

Fun Facts

• Every cell in the body (except red blood cells) contains a full DNA sequence. In theory, you could clone a baby from a toenail, although a stem cell would likely be more malleable.
• If we wanted to store all the digital information in the world, all we would need is 2 grams of DNA components and a way to sequence it.
• A strand of human DNA, unraveled, would be about 6 feet long. However, it is coiled up and highly condensed, so it only takes up .0000035433 of an inch (0.09 micrometers)
• You could fit 25,000 strands of DNA side by side in the width of a single adult hair.
• There were some ancient viruses that used to infect humans but today, 8% of human DNA is actually made of those ancient viruses. Talk about going viral!
• We mentioned earlier humans have 3 billion base pairs in their sequence, but don’t get too cocky about being that complex; the Amoeba dubia have 670 billion base pairs.
• A mud worm is genetically closer to a human than an octopus.
• DNA has a half-life of 521 years. This simply means that the oldest animal or organism that can be cloned back to life cannot be older than 2 million years. Thus, replicating a dinosaur is literally impossible because they went extinct 65 million years ago. Sorry, Jurassic Park.
• DNA sequence convergence of humans with other organisms:
  • Chimpanzee 98%
  • Mouse 92%
  • Zebrafish 76%
  • Fruit fly 51%
  • Banana 50%
  • Weed (thale cress) 26%
  • Bacteria (E coli) 18%
• DNA convergence between humans: 99.1%.  It’s that 0.9% (or less) difference that makes it possible to differentiate between people.

Science-Free Zone

But why, for what should be a travel blog, have I written about human DNA convergence with a banana?  Have I gone half bananas myself? Is my inner banana asserting itself?

Nope. It’s all Jason’s fault. He runs the Halfbananas blog, and has opted to create a Halfbananas award, recognizing bloggers that he enjoys following. I have been named as one of the lucky recipients.

Now I have to admit, the first time I was nominated for an award, the Liebster, I was thrilled. Back then I assumed awards meant you were actually creating exceptional content. This was fed in part by the path the Liebster took to get to me; both the blogger who nominated me and the one who nominated him one generation earlier are both bloggers whose content I consider to be of high quality. But then I started checking out other Liebster winners looking for great blogs to follow, and soon came to the conclusion it was more like a newbies club: it seemed to be as much about calling out newbie friends as blogs that stand out in a crowd. I saw Liebster winners who hadn’t even written 5 posts. The winners were a mixed bag, some good, some just, um, new.  It’s all subjective, in any case. I thought, should another nomination come my way I’d smile internally, ignore it externally, and join the no awards club.

But Jason invented this award, and he has a different, tongue in cheek approach to the whole thing. Apt, since his blog veers to the humorous side. Rather than imposing a set of rules on his victims winners, requiring them to answer a bunch of personal questions and in turn having them torment a new set of folks ala chain letter, his requirements were more on the silly side. His rules:

If you are nominated for a halfbananas award, you should complete one (or more) of the following conditions/tasks:

1. Thank me for the award by making a sizeable donation to my retirement fund.
2. Embark on a quest to locate the lost city of Atlantis and bring me the fabled golden chalice of eternal youth.
3. Invent a time machine and get me the Euro-lottery results for next Friday.
4. Display the award proudly on your blog.
5. All of the above.
6. None of the above.

This is more my speed. It still suggests blogs that might be worth a look, doesn’t get too personal,  and doesn’t take itself too seriously. And besides, I kind of like the award logo. Resonates with my inner banana. Not to mention, it inspired me to research the whole DNA thing.

I have chosen to find the lost city of Atlantis. Atlantis itself turned out to be an island kingdom, surrounded by ocean. I passed on drinking from and returning the chalice; turned out it goes along with hell’s own hangover, and I don’t want to live forever with one of those. Here’s a picture of Atlantis’s ocean from the shoreline:

Jason did call out a number of his favorite bloggers in his awards post, earnestly – not facetiously, but has not required that I do so as well. So I won’t, at least today. However, should you be inspired by his example, feel free to pass it on. The only rules:

• Call out blogs you think are noteworthy, with an apology to all the followers/blogs you didn’t mention due to practicality.
• Make up your own rules. In keeping with the Halfbananas ethos, they should be non-onerous and preferably tongue in cheek.

In the meantime, channel your humane human, and should you go bananas, don’t get too rotten.

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References:

• 25 Interesting DNA Facts
• Amazing DNA Facts
• What is DNA?
• Sizing up genomes: Amoeba is king