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The complete sequence of a human Y chromosome

nature.com

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Re: The complete sequence of a human Y chromosome

#131

Post by borissk »

pmoriarty wrote: post #122
borissk wrote: post #37

Earlier quoted context omitted.

I'm curious if these 750MB + the DNA of mitochondria + the protein metagenomics contain all the information needed to build a human, or if there's extra info stored in the machinery of the first cell. That is if we transfer the DNA to an advanced alien civilization - would they be able to make a human.

"if we transfer the DNA to an advanced alien civilization - would they be able to make a human." I'm really surprised that in all these responses to your question no one's mentioned the womb or the mother, who (at least with current technology) is still necessary for making a human. That's not to mention the necessity of the egg. We're not just DNA.

Instructions on how to make a womb and an "egg" are contained within the human DNA.

Re: The complete sequence of a human Y chromosome

#132

Post by globular-toast »

xwdv wrote: post #50

Could we in theory just build up any kind of creature from scratch if we write out its genome? How would we compile it into organic matter?

There's a bootstrapping problem. You need something to run the code. An egg cell and sperm cell contain loads of other stuff in addition to the genome and the only way to get that stuff is from the genome...

It's like if you had a program to 3D print a 3D printer but you don't have a 3D printer that can read that program.

It's all ridiculously complicated. To get an idea about it you could learn about how simple RNA viruses like influenza or HIV replicate. It's easy enough for anyone to understand. But no single person can fully understand humans (or other mammals, plants etc, we're not special in that respect).

Re: The complete sequence of a human Y chromosome

#134

Post by dchftcs »

pmoriarty wrote: post #122
borissk wrote: post #37

Earlier quoted context omitted.

I'm curious if these 750MB + the DNA of mitochondria + the protein metagenomics contain all the information needed to build a human, or if there's extra info stored in the machinery of the first cell. That is if we transfer the DNA to an advanced alien civilization - would they be able to make a human.

"if we transfer the DNA to an advanced alien civilization - would they be able to make a human." I'm really surprised that in all these responses to your question no one's mentioned the womb or the mother, who (at least with current technology) is still necessary for making a human. That's not to mention the necessity of the egg. We're not just DNA.

This is a question about theoretical possibilities and what you're saying seems to be a rigid belief in an answer "no". But you provided no evidence or justification, except for "with current technology", which answers nothing about the theoretical question.

Re: The complete sequence of a human Y chromosome

#135

Post by BbzzbB »

tobinfricke wrote: post #70
brayman30 wrote: post #3

This 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.

What makes the Y chromosome more difficult?

Maybe someone can correct the details since it's been a few years I done this, but we sequence DNA by PCR. Roughly, (1) breaking it up in small pieces and split strands, (2) mixing it with an enzyme that completes each single strand, (3) repeat 1 and 2 a bunch to multiply the strands many times over to make the solution a sense DNA juice, (4) pass it through a machine that'll sequence thousands of these small strands and (5) align these short DNA sequences with a software that matches unique sequences.

I did it with COI gene, which is just a short (1000ish base pairs with our snails IIRC) sequence of purely random ATGC base pairs. Lots of unique sequences make the short strands easy to match, just get a bunch of 10-15 BP bits and you can match the whole thing.

Now if your gene is 62M BP of repeating palindrome sequences, you can imagine how hard it would be to align random pieces sequenced as it will be very hard to find unique sequences to match.

Re: The complete sequence of a human Y chromosome

#136

Post by inciampati »

BbzzbB wrote: post #135
tobinfricke wrote: post #70

Earlier quoted context omitted.

What makes the Y chromosome more difficult?

Maybe someone can correct the details since it's been a few years I done this, but we sequence DNA by PCR. Roughly, (1) breaking it up in small pieces and split strands, (2) mixing it with an enzyme that completes each single strand, (3) repeat 1 and 2 a bunch to multiply the strands many times over to make the solution a sense DNA juice, (4) pass it through a machine that'll sequence thousands of these small strands…

We don't use PCR anymore! It's direct sequencing of the primary DNA. We can read single molecules. That's the quiet revolution in nanotechnology that's driving all these complete assemblies.

Re: The complete sequence of a human Y chromosome

#137

Post by mjan22640 »

borissk wrote: post #37
cvoss wrote: post #33

Earlier quoted context omitted.

It's a slight exaggeration of the information content to report the data size using an ASCII encoding. Since there are 4 bases, each can be encoded using 2 bits, rather than 8. So we're really talking 750 megabytes. But still mind-blowing.

I'm curious if these 750MB + the DNA of mitochondria + the protein metagenomics contain all the information needed to build a human, or if there's extra info stored in the machinery of the first cell. That is if we transfer the DNA to an advanced alien civilization - would they be able to make a human.

Imagine a machine shop that has blueprints of components of the machines they use in the shop, and processes to assemble machines from the components. When a machine shop grows large and splits in two, each inherits a half of shop with the ongoing processes and a copy of the blueprints. https://m.youtube.com/watch?v=B7PMf7bBczQ&pp=QAFIAQ%3D%3D

DNA is the blueprints. There are infinite possibilities what to do with them. The advanced civilization would need additional information, like that they are supposed create a cell from the components to begin with, and a lot of detailed information how exactly to do that.

Edit: improved clarity

Re: The complete sequence of a human Y chromosome

#139

Post by Angostura »

dekhn wrote: post #47
borissk wrote: post #37

Earlier quoted context omitted.

I'm curious if these 750MB + the DNA of mitochondria + the protein metagenomics contain all the information needed to build a human, or if there's extra info stored in the machinery of the first cell. That is if we transfer the DNA to an advanced alien civilization - would they be able to make a human.

This is a complex question. The cocktail soup in a gamete (sperm or egg) and the resulting zygote contains an awful lot of stuff that would be extremely hard to replace. I could imagine that if the receiving civilization was sufficiently advanced and had a model of what those cells contained (beyond the genomic information) they could build some sort of artificial cell that could bootstrap the genome to the point of…

I’m just pondering this, and it’s not clear to me that there is anything intrinsic in the genome itself that explicitly’says’ “this sequence of DNA bases encodes a protein” or even “these three base-pairs equate to this amino acid”.

I wonder if that information could ever really be untangled by a civilisation starting entirely from scratch without access to a cell

Re: The complete sequence of a human Y chromosome

#140

Post by dwattttt »

chihuahua wrote: post #9
jshorty wrote: post #6

Could 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?"

You could say exactly the same of all data; it's just 1s and 0s, but when I look I just see blonde, brunette.
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