HowDoesLifeWork#06_The fission
The fission
Version française : Steemit | Busy
What means this title? I put this title to explain you, bacteria reproduction. Yes, bacteria reproduce them by fission, this is an asexual reproduction, that, means that they don’t need a partner. Strange no?
Indeed, the father individual becomes two child individual which are the same between them and with the father individual. In sum, these are clones, with the same genetic information (the same DNA coil in the two child individuals).
But then, how DNA has one copy in each cell/ bacteria?
You said it! One copy of each individual, that imply that DNA “clone itself”. This phenomenon is called DNA replication, it’s an important process (there will a chronicle on this).
That’s all for bacteria reproduction!
Rigorously we can't say that it’s a reproduction in the term strict sense.
Yes, we talk about reproduction when there is a genetic mixing (genome modification). Mmmmh that’s true when we think about that…
How a bacteria which divide itself (which clone itself roughly) changes his genetic code in order to evolve?
Let’s discuss bacteria evolution, how they change their genomes?
First, there are mutations, they occur during the DNA replication, eh yes, this mechanism is not perfect. There may is an error in the copied genetic sequence; an A becomes a T, a G becomes an A, …
Then there are genetics recombination, this phenomenon is in the same register than mutations. This is also the fault of DNA replication (decidedly), in this case, this is outright a part of the sequence which changes his place in the genome. Father and Child will have different sequences but with the same amount of A, C, T and, G. You follow me?
Consequently, these mutations or recombination change coded function in DNA (one base mutation can fully shut down a gene working, or don’t have an effect). Evolution generated by these two phenomena is chancy, because it’s the result of an error, besides it’s a very slow evolution. Indeed, novel function acquisition needs a big amount of generations. Is like finding a word at Scrabble with blinded eyes.
And if you can’t find a word at Scrabble you, generally, pick letters (even the full word) to your neighbor. Bacteria are also cheaters!
That is called lateral gene transfer, as his name indicates it’s a gene transfer from a bacteria to another. The lateral adjective is opposed to vertical which is simply from father to child. Lateral gene transfer allows a faster and oriented evolution.
This phenomenon can be achieved by 3 ways:
- The bacterial conjugation: two bacteria of the same species link them to transfer a small DNA piece, generally it’s a plasmid. Of course, the giver keeps a copy and the receiver checks if he has already this DNA piece (have in double is useless). It’s a high energy process but the two bacteria stay alive.
- The bacterial transformation: have you already find something in a bin? Never for me… The transformation is the acquisition, by a bacteria, of a DNA piece find on dead bacteria.
- Transduction: gene transfer by a virus, virus infect the bacteria but integrate a DNA piece from his. During the virus propagation, he carries out the DNA piece from the bacteria and could transfer it to another bacteria which will infect. Who manipulate who in this story?
Of course, I will go back on these strange things that are viruses.
Référence :
https://fr.wikipedia.org/wiki/Scissiparit%C3%A9
https://fr.wikipedia.org/wiki/Transfert_horizontal_de_g%C3%A8nes#Procaryotes
https://fr.wikipedia.org/wiki/Recombinaison_g%C3%A9n%C3%A9tique
https://fr.wikipedia.org/wiki/Prokaryota#Croissance_et_reproduction
https://fr.wikipedia.org/wiki/Conjugaison_(g%C3%A9n%C3%A9tique)
https://fr.wikipedia.org/wiki/Transformation_(g%C3%A9n%C3%A9tique)
What this Dr.Plantes want me?
#01_Where are we? What time is it?
#02_The bacteria
#03_The DNA
#04_The evolution
#05_The cell
Hey I really like that you are going for steemstem and a science blog, but here are some things you should work on to get more attention. First of, try to find better sources. Yes, wikipedia is a good starting point, but maybe you can find some review articles about bacterial fission on NCBI or google scholar. Second, you English is a little bit awkward. Third, try to be a bit more original. Like, why would anybody care about bacteria, how can this be used for future research... Stuff like that. Please understand this as constructive criticism. I want other science writers to be succesful here! I hope this helps and I these tips help you. Good luck;) I will follow you and I am looking forward to your next post. Cheers!
First of all, thank very much for this constructive comment!
Yes, I agree with you on the sources. Actually, I use Wikipedia sources to prove that what I say is correct, because all the things I said for the moment are from my courses, but I can't quote my courses. Of course, I look before on the Wikipedia page to see if it's correct. But you right, I will put more scientist article and reviews for next chronicles!
My English... Arf... Yes, this is my big problem, this is not my native language and I never been good in English. But actually, I'm in Australia to improve my English, so, writing my chronicles in English help me for that. I hope that this doesn't prevent to understand my posts...
I try to take relevant and original analogies to explain life process, this is my way to be original. I chose to not explain how sciences work, this is why I never speak about techniques or perspectives. Also for the moment, we don't deal with very original subjects, these first chronicles are to defines some process to understand better the more complex chronicles.
Thank you @lesshorrible and hope that you will prefer the next chronicles!
Again, this was not that I dislike what you doing. This was intended to be helpful to you! Hope you did not think this was too harsh. All the best and Cheers!
No, it's fine! We need harsh criticisms!