Recent comments in /f/askscience

severoon t1_jbouxw9 wrote

Reply to comment by RaptureAusculation in I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

Also consider that "life" is likely to be an arbitrary feature in this discussion.

If you have a molecule that happens to be an enzyme which builds itself, you have yourself a self-replicating thing. Is it "alive"? Definitely not.

Well that's one feature of "life" but it's one that most people tend to think of only in the context of life. But all the features we typically think of in the context of life exist in much simpler, not-alive things.

By looking for the simplest thing we consider "alive," no matter how we define that, it's likely to end up being much simpler than what we would feel comfortable calling "life."

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Oknight t1_jboub3m wrote

Reply to I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

I understand a virus to be more like a chain letter than an "organism" -- a package of information that induces an information processing system to make copies of itself, but I believe you need the information processing system functioning, like a living cell, to make the copies or the virus doesn't do anything.

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UnfinishedProjects t1_jbou27j wrote

Reply to comment by Dr_Vesuvius in I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

You made me understand primordial soup for the first time. I mean I understood what they meant but I never thought about it being an actual soup of all the required ingredients.

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danby t1_jbopbwg wrote

Reply to comment by ThorsTacHamr in I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

Minimal genome experiments generate organisms that aren't free living so they aren't really aimed at generating something like the LUCA. Mostly these experiments are trying to discover the minimal set of house keeping genes that can maintain a living cell, there's no reason to believe the LUCA was like that, nor any reason to believe that the LUCA had a minimally sized genome.

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triklyn t1_jboowgm wrote

Reply to I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

probably yes. there are probably minimum functions that are required based on minimal protein combinations, and minimum basepairs necessary for read/write.

there is definitely a minimum. what that is... would take a bunch of testing. and that does not exclude future mutations producing reduced requirements either.

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Tropenpinguin t1_jboo3zp wrote

Reply to Why are Y chromosomes shorter than the X chromosome? by Which-Community-5851

Y chromosome in humans are getting shorter. It loses around 10 genes per million years. At this rate it will be gone in four and a half million years. Also sex-determination doesn't only involve the Y chromosome, but around 60 genes working in concert all over the genome.

You only want human facts? I've got some pretty interesting animal facts for the Y chromosome.

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HermanCainsGhost t1_jbon0d6 wrote

Reply to comment by Beliriel in I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

The “RNA world hypothesis” was what I was taught in my upper level genetics class back in 2004, so unless I am out of the loop and it has been discarded in the 20 years since, it sounds accurate to me

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throwawaystitches t1_jbomr6c wrote

Reply to comment by udee79 in I just learned that the known shortest DNA in an “organism” is about 1700 base pairs in a certain virus. Is there a minimum amount of “code” required for an organism (or virus) to function in any capacity? by mcbergstedt

So there's autotrophs and heterotrophs, which has to do with where you get your carbon (C atoms). If you're an autotroph, you can transform (or "fix") inorganic carbon (like in CO2) to organic carbon, which are molecules that contain hydrocarbons or hydrogen-carbon bonds. Heterotrophs can't do that. They have to consume organic carbon to use it.

This is what determines if you are a primary producer or not. If you are an autotroph, then you are a primary producer. If you are a heterotroph, you must consume other organisms to get your carbon and are a consumer (note that there are primary consumers, who consume primary producers).

Then there's where you get your energy. If its chemicals, then you're a chemotroph. If its light, then you're a phototroph. If its both, congrats, you're a mixotroph.

You can mix these up. You can be a photoautotroph that gets your energy from the sun and fixes carbon. Cool, you're probably a plant or cyanobacteria. You could also be a chemoheterotroph that must consume your carbon and obtains energy from the chemicals you consume. Dang, you're probably a human.

Chemosynthesis and photosynthesis refer to autotrophic processes so they are primary producers. But the reason isn't because they utilize chemicals to get energy, its because they fix carbon in the process.

Sorry for writing this all out. I'm trying to procrastinate. Thank you for your help.

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