Recent comments in /f/askscience

VonGooberschnozzle t1_jbnpy5x 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

Spiegelman's Monster is the minimum viable RNA chain, made by selecting the fastest breeding viruses. 48 or 54 nucleotides is the smallest: https://en.wikipedia.org/wiki/Spiegelman%27s_Monster

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Major_t0Ad t1_jbnnlhz 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

There is selection pressure to strip away genes you don't need because the investment for offspring is smaller. Environmental bacteria tend to lose genes quite quickly, e.g. when they enter simple growth medium in the lab because they don't have to "fight" for survival in harsh conditions.
So when you find organisms they kind of already have the 'minimum set' for their respective environment. The smallest DNA for a free-living organism is around 1.3 Mbp with 1354 encoding genes (Marine bacteria Pelagibacter ubique)

https://doi.org/10.1126/science.1114057 Publication figure 1 shows different species, also mycoplasmum, in a scatter plot genome size over number of genes.

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Jale89 t1_jbnneoi 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

No: this is more like comparing a Raspberry Pi to a full modern PC - all the same modern bits but simpler. Comparing to the first life on earth would be like the first computers, with radically different components and operating principals to achieve the same functions.

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blauw67 t1_jbnlg26 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

There's actually viroids, Virus like "Organisms" that infect only flowering plants. They are basically free floating pieces of genetic material without a protein shell. Avsunviroid seems to be one of the smallest with only 246 nucleotides.

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Tsunnyjim t1_jbnjppv wrote

Reply to Human to Primate blood transfusion possible? by Lost-Wash-5521

There are a lot more markers in your red blood cells than just Rhesus and ABO grouping.

Plus there a whole lot of other things in blood, like your white blood cells, platelets and plasma.

It's theoretically possible, but not likely, as any one factor being off can lead to rejection. Heck, it's tricky enough getting human blood transfusions right. It's more likely that blood plasma can be used, since it removes the majority of the cellular content, but I don't know that anyone has done a comparative study on human and primate blood plasma.

Also, I feel you are getting two things confused here. Blood transfusions are one thing; horse, donkey, mule genetics is a whole different thing.

Humans and primates are different species with no ability to mate with viable offspring.

Horses and donkeys are also separate species, but are closely enough related that they can mate and produce a sterile hybrid mule.

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Ragondux t1_jbni1gv 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

For this to work you need to have a cell will enzymes and ribosomes to be able to use the DNA to make proteins It's likely that the first living organisms were simpler and then built all this machinery.

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Jale89 t1_jbnh2q1 wrote

Reply to comment by FrostReaver 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

As far as I am aware, this is currently our best answer. I saw a talk by the Primary Investigator in 2015 - I recall that they were basically knocking out every gene. We had a brief conversation about an area they hadn't explored where they could potentially go even further, if there are genes sets where knocking out only single components was lethal, but knocking out the whole set was survivable, so there's potential to go even further.

OP, the virus mentioned doesn't really represent an organism because it requires the mechanisms of a cell to replicate. The organism that FrostRever mentions here exists in "axenic culture", which means there are no other species present at all.

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FrostReaver t1_jbnfnyw 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

There is a concept call the minimum viable cell, where researchers attempt to splice almost all genes from a Mycoplasma mycoides except what is needed for survival. The genes that are necessary include metabolic proteins that handle essential functions like reproduction, fermentation, and amino acid synthesis.

"It has a smaller genome (531,490 bp) than that of any known organism that can be grown in axenic culture. There are only 438 protein-coding genes and 35 RNA-coding genes (Hutchison et al. 2016)."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710109/#:~:text=A%20minimal%20cell%20is%20one,genes%20and%20components%20are%20understood.

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