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The complete sequence of a human Y chromosome
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Re: The complete sequence of a human Y chromosome
#12Could someone explain exactly what it means to be "completely sequence" the human genome when all humans have distinct genetic makeup (ie, different sequences of nucleobases in their DNA/RNA)?
They mean they have obtained the complete sequence for a particular Y chromosome that is considered to be a "reference" chromosome. This is similar to what was done for all the other chromosomes.
Re: The complete sequence of a human Y chromosome
#13Could someone explain exactly what it means to be "completely sequence" the human genome when all humans have distinct genetic makeup (ie, different sequences of nucleobases in their DNA/RNA)?
I've never understood this either. I assume the genome is many megabytes of [ATCG]+. If we have that sequence, what does it tell us? Do we look at it and say "Ah, yes, ...ATGCTACGACTACGACTAGCG... very interesting?"
Many genes are highly conserved or consistent enough. E.g.: if there's a 1% difference between two people, then it's a bit like two very unique sentences that have a couple of small typos. They're sill recognisable, and it's also still pretty obvious that they're the "same".
A gene sequence allows researchers to determine the amino acids that are coded for, and from those, which proteins match which genes.
This can be matched up with genetic diseases. If you know that damage to a certain location in a chromosome causes a problem with a certain biological process, then ergo, the associated protein is needed for that process!
So: genetic illness -> gene sequence -> protein -> role in the body
Without sequencing, that chain can't be built.
Re: The complete sequence of a human Y chromosome
#14For a very entertaining and educational book that tangentially related; I can highly recommend: Y - The Descent of Man by Steve Jones [0] I am thrilled to see more chromosomes being mapped/sequenced. Please excuse my high-school level of biology knowledge here, but have we definitively progressed beyond correlation when it comes to genes, gene expression, and how they all interact? Take "Blue eyes" as an example, we…
I would imagine all sorts of genes are necessary to have blue eyes depending on how you look at it. After all, you need eyes in order to have blue eyes, and a whole bunch of other machinery to open them to check the color...
Re: The complete sequence of a human Y chromosome
#15Could someone explain exactly what it means to be "completely sequence" the human genome when all humans have distinct genetic makeup (ie, different sequences of nucleobases in their DNA/RNA)?
I had the same question. Perhaps this will help you. https://en.m.wikipedia.org/wiki/DNA_sequencing
That page describes the human genome as having been sequenced back in 2003. *confusion intensifies*
Re: The complete sequence of a human Y chromosome
#16[flagged]
Re: The complete sequence of a human Y chromosome
#17Could someone explain exactly what it means to be "completely sequence" the human genome when all humans have distinct genetic makeup (ie, different sequences of nucleobases in their DNA/RNA)?
I've never understood this either. I assume the genome is many megabytes of [ATCG]+. If we have that sequence, what does it tell us? Do we look at it and say "Ah, yes, ...ATGCTACGACTACGACTAGCG... very interesting?"
For the same reason Monsanto sequences basically anything: Because we can tell what proteins are encoded in there, and what is near them, and we can have good ideas of what proteins are expressed together. When dealing with genetic modification, we get to see whether our modification went in, and where it landed: Having a protein in a genome isn't enough. Its expression might be having an effect on other things, depending on where it is.
When we have baselines, we can compare different individuals, and eventually make predictions of how they are going to be based solely on the genetic code. If I know that a certain polymorphism is tied to some trait I want, I might not have to even bother spending the time growing a plant: I know that it's not what I want, and discard it as a seed.
With humans we are probably not going to see much modification soon, but just being able to detect genetic diseases, risk factors for other diseases that have genetic omponents, or allow for selection of embryos in cases of artificial insemination is already quite valuable.
It's not source code that we are all that good at understanding just yet, but there's already some applications, and we have good reason to think there's a lot more to come
Re: The complete sequence of a human Y chromosome
#18As I understand it this was hard because most mechanisms we have for sequencing genes work by first splitting large sequences of genes into random chunks and sequencing each chunk individually. These chunks then need arranged properly to form the entire genome. This is possible at all because we can get overlap between the chunks, but when a sequence has repeating sections overlap still isn’t enough to stitch everything together correctly. There’s also a newer technique involving nano pores. The dna is literally pulled through a little hole and the electrical properties change depending on which base pair is inside the pore, sadly it’s liable to errors in a deterministic way depending on the sequence. I don’t have access to the full paper so I’m not quite sure what was done here, but I have heard people talk about combining the two approaches above
Re: The complete sequence of a human Y chromosome
#19This is actually kind of a huge deal since it means that all 24 chromosomes have now been fully sequenced. As it says in the abstract, up until now the Y chromosome proved difficult to sequence due to its nature.
You can tell it's the Y chromosome because of the way it is.
Re: The complete sequence of a human Y chromosome
#20Could someone explain exactly what it means to be "completely sequence" the human genome when all humans have distinct genetic makeup (ie, different sequences of nucleobases in their DNA/RNA)?
I've never understood this either. I assume the genome is many megabytes of [ATCG]+. If we have that sequence, what does it tell us? Do we look at it and say "Ah, yes, ...ATGCTACGACTACGACTAGCG... very interesting?"
It's just about 3 gigabytes (each byte a letter). Pretty mind-blowing, if you ask me.