How do genetic replication and mutations occur?

[bbbbb]

How do genetic replication and mutations occur?
Wouldn't it be simpler if everything remained in a static state?
And how does transcription sometimes turn out to be inaccurate? What makes it go wrong?

[Sensei]

1 hour ago, bbbbb said:

How do genetic replication and mutations occur?
Wouldn't it be simpler if everything remained in a static state?

In static world there is no change. No progress.

Quote

And how does transcription sometimes turn out to be inaccurate? What makes it go wrong?

1) decay of radioactive isotope of Carbon C-14. Carbon is part of DNA/RNA. Affected molecule is fatally damaged. Surrounding molecules can be damaged too by highly accelerated electron.

https://en.m.wikipedia.org/wiki/Carbon-14

2) decay of radioactive isotope of Potassium K-40. Potassium is not part of DNA/RNA, but is present in blood and cells. It has a long half-life but has much larger abundance % than C-14 to C-12.

https://en.m.wikipedia.org/wiki/Potassium-40

3) cosmic radiation from the Universe.

4) UV radiation from the Sun.

5) normal chemical reactions can produce intermediate chemical compounds which have unpaired electrons therefor are extremely reactive and unlucky DNA/RNA molecule might be damaged in unexpected way.

6) carcinogenic food and drinks.

https://www.google.com/search?q=carcinogenic+food+and+drinks

7) carcinogenic environment.

https://www.google.com/search?q=carcinogenic+compounds

 

Edited April 5, 2021 by Sensei

[Ericchiriboga]

Genetic replication is the product of a series of several enzymes working in concert, the main one of which is DNA polymerase, which is what actually builds the new DNA strands. There's also an inherent error rate in DNA polymerase. The errors are checked and "proofread" and fixed, but it's not a totally perfect process and some slip through the cracks, creating mutations in the newly synthesized strands. There are other ways mutations can occur, including being spurred by radiation, but that's the best, easiest way to think about it in my opinion.

And without mutations, species would never change. If 2 different species had 2 different DNA polymerases, one of which replicates with 0 errors, then all the members of that species would stay the same while members of the other species would slowly change and the ones who changed for the better would reproduce and eventually the species with the error-prone DNA polymerase would be more fit to survive in their environment.

[bbbbb]

On 4/5/2021 at 1:20 PM, Sensei said:

In static world there is no change. No progress.

This is exactly what I am asking, why is there any progress at all.

And thanks to both of you for the answers

[Ericchiriboga]

50 minutes ago, bbbbb said:

This is exactly what I am asking, why is there any progress at all.

And thanks to both of you for the answers

Because environments and conditions change so if a species couldn’t change with their environment, they would die off. 

[Sensei]

9 minutes ago, Ericchiriboga said:

Because environments and conditions change so if a species couldn’t change with their environment, they would die off. 

In static Universe, atoms could not form in the first place, stars could not form, planets could not form, galaxies would not exist etc. etc. It has nothing to do with strict biology.

[Ericchiriboga]

40 minutes ago, Sensei said:

In static Universe, atoms could not form in the first place, stars could not form, planets could not form, galaxies would not exist etc. etc. It has nothing to do with strict biology.

This is true, but I was just focusing more on the context of the question.

[bbbbb]

3 hours ago, Ericchiriboga said:

Because environments and conditions change so if a species couldn’t change with their environment, they would die off. 

This proves that it did, but it does not explain how it happens.

[Ericchiriboga]

17 minutes ago, bbbbb said:

This proves that it did, but it does not explain how it happens.

Well, you can always go deeper and deeper in terms of "how" and really get to the fundamental underpinnings of how things work. If you're looking for the biophysics of the molecular interactions guiding it, I'm not really qualified to answer. But if you're just looking for a better understanding of evolution, maybe I can give a basic framework.

The main forces acting are called Genetic Drift, Gene Flow, and Natural Selection. Mutations will occur in DNA, creating variability from individual to individual in a population. Some mutations will be more favorable for the environmental conditions and if they confer an advantage to the individual, then the individual will reproduce more, passing that mutation along and increasing its prevalence in the environment. This is the "survival of the fittest" that people talk about and a big factor in speciation, as isolated groups could slowly evolve in different ways until they become different species. Now, if we think about evolution in terms of a change in the percentage of a population that has a certain mutation, it's easier to think about Gene Flow and Genetic Drift. Gene Flow is individuals migrating to and from a population and Genetic Drift is the random change in a population's makeup, which can be easily visualized by thinking about a natural disaster randomly killing some members, regardless of their "fitness." These all work in concert.

That's a very simplified explanation, and obviously there's much more to it than that. But I hope it helps.

[bbbbb]

On 6.4.2021 at 10:11 PM, Ericchiriboga said:

ובכן, תמיד תוכלו להעמיק יותר ויותר במונחים של "איך" ובאמת להגיע לתשתית הבסיסית של אופן פעולתם של הדברים. אם אתם מחפשים את הביופיזיקה של האינטראקציות המולקולריות שמנחות אותה, אני לא ממש כשיר לענות. אבל אם אתה רק מחפש הבנה טובה יותר של האבולוציה, אולי אוכל לתת מסגרת בסיסית.

הכוחות העיקריים הפועלים נקראים סחיפה גנטית, זרימת גנים ובחירה טבעית. מוטציות יתרחשו ב- DNA, ויצרו שונות מאדם לאדם באוכלוסיה. מוטציות מסוימות יהיו חיוביות יותר לתנאי הסביבה ואם הן מקנות יתרון לאדם, אז הפרט יתרבה יותר ויעביר את המוטציה הזו ויגביר את שכיחותה בסביבה. זהו "הישרדותם של החזקים ביותר" שאנשים מדברים עליהם וגורם גדול בספציציה, שכן קבוצות מבודדות יכולות להתפתח לאט בדרכים שונות עד שהן הופכות למינים שונים. כעת, אם נחשוב על האבולוציה במונחים של שינוי באחוז האוכלוסייה שיש לה מוטציה מסוימת, קל יותר לחשוב על זרימת גנים והיסחף גנטי. זרימת גנים היא אנשים הנודדים לאוכלוסייה וממנה, וההיסחפות הגנטית היא השינוי האקראי במערך האוכלוסייה, שניתן לדמיין בקלות על ידי חשיבה על אסון טבע ההורג באופן אקראי כמה חברים, ללא קשר ל"כושרם ". כל אלה עובדים בקונצרט.

זה הסבר מאוד פשוט, וברור שיש בזה הרבה יותר מזה. אבל אני מקווה שזה יעזור.

Thank you