Scientists Finished Sequencing the Human Genome
However, they haven't finished decoding it... yet
Hiya!
Humans are amazing. Truly. We’ve learned so much about the world and our universe. We learned to fly and construct massive structures; we’ve even imagined then created complex artificial ecosystems called cities and governments. Yet, we still don’t totally understand ourselves — even our bodies still contain plenty of mystery.
When we want to learn something, it’s good to begin at the core and branch out from there. So, if we want to unravel the enigma that is us, then studying our DNA is a great starting point. Then again, it’s easier said than done. Thankfully, as technology advances, it brings us closer to finding answers.
What Exactly is the Human Genome?
I’ll be honest. I thought the human genome and DNA were just two terms for the same thing for a long time. I was close, but it turns out they’re actually different.
DNA, or Deoxyribonucleic acid, is the chemical compound containing the instructions to create and instruct the activities of living things. A DNA strand, also known as the double helix, consists of the two twisting strands we’re familiar with.
If we were to zoom in on these strands, we’d see they’re made of four chemical units — adenine (A), thymine (T), guanine (G), and cytosine (C) — which are called nucleotide bases. We’d also notice a pattern in their order. An A base on one strand always pairs with a T base on the opposite strand. Similarly, a G base always pairs with a C base across from it.
I know. It’s more complicated than I assumed going into this.
The National Human Genome Research Institute (NHGRI) attempts to simplify it.
The order of the As, Ts, Cs and Gs determines the meaning of the information encoded in that part of the DNA molecule just as the order of letters determines the meaning of a word.
Basically, everything about who we are results from the order and pairing of these four chemical units along the two twisting strands of the helix. A single alteration in your nucleotide bases, and you’d be very different than you are today.
While DNA consists of the patterns and pairing of the bases, the genome is the complete set of DNA. The same article mentioned before breaks this down too.
Virtually every single cell in the body contains a complete copy of the approximately 3 billion DNA base pairs, or letters, that make up the human genome. With its four-letter language, DNA contains the information needed to build the entire human body.
I’ve always known DNA is important and specific for each person. But I don’t think I ever fully grasped the magnitude of its importance or ingenuity of its complexity. No wonder scientists have had trouble trying to understand it. Still, they've done a pretty good job so far.
Beginning in 1990, experts at the National Institutes of Health (NIH) by the NHGRI conducted the infamous Human Genome Project with the goal of sequencing and mapping all of the genes within the genome. By 2003, they had completed about 92 percent of it — including 23 pairs with 46 chromosomes, representing tens of thousands of individual genes.
Then they hit a wall.
Despite their progress, there were gaps in the genome that technology at the time couldn’t resolve. They continued trying various methods over the last two decades, but without much luck, until recently, that is.
The Entire Human Genome is Now Mapped
Over the last couple of decades, technological advancement allowed scientists new paths to study the human genome. In the process, six research papers, all published in Science, provide the most comprehensive genome sequencing for any mammal yet. The most recent was published last month, in March of 2022.
Adam Phillippy is the senior author of one of the new papers and the head of genome informatics at the National Institutes of NHGRI. He explained to Time magazine that the prior Human Genome Project used blood draws to obtain people’s DNA, which was the technology used at the time. The problem was that it introduced errors and gaps that have remained for years. But now, we can correct past mistakes and fill in the gaps.
The newly sequenced regions include almost 200 million base pairs and access to previously missing sections like the centromeres — responsible for keeping both strands of the DNA helix organized while they perform their duties.
This may seem like no big deal, but centromeres play a massive role in neurodegenerative diseases and brain growth. They’re also crucial for normal human development. In fact, we’re not the only species to have centromeres; all eukaryotes have them — as in all plants and animals or any “higher organism.” So, ya know, kind of a big deal.
But wait, there’s more!
Before, scientists noticed repeated sequences along long stretches of DNA, which they assumed were errors and often dismissed them as “junk DNA.” Turns out, these repeated sequences might actually have a role to play with some human diseases.
One of the papers found these repeated sequences are different in primates and appear in other parts of the genome — meaning at least some of what scientists previously thought was junk may actually be a key for humanity.
Side note: maybe it’s just me, but I don’t think Nature creates anything without a purpose. So seems a bit silly to declare something as “junk” just because we haven’t figured out its reason for existing yet. Especially when that “junk” involves the very coding of life.
What’s Next?
Now that scientists fully sequenced the human genome, the next step is to decode everything they’ve found. Mapping the genome is one thing, but understanding it is a whole other mountain to climb. But the possibilities are endless — for better or worse.
The most apparent benefit of deciphering the genome is the potential to create precise medicines and therapies. At the very least, it will help experts understand diseases better.
Also, while the Human Genome Project used DNA from blood taken from dozens of people, the recently published completed sequence of genetic material belonging to a single human. So it would be good to expand the study, which is exactly what the Human Pangenome Reference Consortium wants to do. Their goal is to sequence the genomes of people from all over the world!
Perspective Shift
Humans are complicated, but it goes far beyond our wishy-washy moods and social dramas. Our complexities extend to a cellular level. Decoding our DNA would be the ultimate “know thy self” accomplishment.
Future research could offer cures to countless diseases and save millions of lives. Though the ripple effect of longer lives, more humans, and less habitable space on the planet might become an unintended disaster. And let’s face it, any new information in the hands of humans means ethical limits will be pushed, and some people are bound to abuse the knowledge. The outcome of which is probably better suited for a sci-fi novel than reality if you ask me.
Still, having a complete understanding of the human genome could open new doors that we didn’t know existed. Could it answer questions about the mind? Might the answer to our unique consciousness lie in the pattern of our DNA? I suppose the only way to know is to keep learning.
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