I don’t know too much about the subject, but maybe this almost 30 year old article can help. There’s more specific examples in the article, but this quote captures the direction:
“I don’t believe in junk DNA,” said Dr. Walter Gilbert of Harvard University, a pre-eminent theoretician of the human genome. “I’ve long believed that the attitude that all information is contained in the coding regions is very shortsighted, reflecting a protein chemist’s bias of looking at DNA.” Coding regions may make the proteins that are dear to a chemist’s heart; but true biologists, he added, know that much of the exquisite control over these proteins is held offstage, nested within the noncoding junk.
There are plenty of plants that execute the exact same functions with code thousands of times smaller.
To say every codon has a purpose is to be ignorant of how evolution works. There are start triplicate pairs and stop triplicate pairs, the regions between stop and start don’t need to have function, even structurally, otherwise why would chromosomes come in different lengths? There was no creator of the genome, there was no efficiency driven outcome, there’s only descent with modification, things just happen to with the way they work, and that’s beautiful in it’s own way.
Again, and I can’t emphasize this enough, this is not my area of study and seems like you have better handling of the subject. But when I read his quote, this part sticks out to me:
much of the exquisite control over these proteins is held offstage, nested within the noncoding junk.
Additionally, the article calls into question the role of code and protein production as the only role for DNA.
Still other noncoding stretches may be buffers against precipitous change, serving rather as flak jackets to absorb the impact of viruses and other genetic interlopers that infiltrate an animal’s chromosomes. Without all the extra padding to absorb the blows, viruses or the bizarre genetic sequences that hop and skip from one part of the chromosome to another – mysterious genetic elements called transposons or jumping genes – might land smack in the middle of a crucial gene, disrupting its performance.
So there maybe stretches of DNA that don’t participate in protein construction, but still has a role. So I question I idea of centering one type function over another.
@TempermentalAnomaly@morphballganon
Junk dna was junk science from the start for ignoring that evolution often eliminates or reduces useless things, like eyes in cave fish, so there’s little likelihood that there’s useless parts of the genome.
But it doesn’t do that instantly and it does it for good reason, eyes and the sections of the brain using them require energy and are vulnerable to infection so in situations where they don’t provide an advantage they increase the likelihood of death before breeding thus giving any offspring born with less energy devoted to eyes has a small advantage which over s very long time results in them being selected away.
So unless the creatures reach a perfect form for their environment then they’ll always be in the process of changing and have some of the old junk in there. Also if the formerly useful part doesn’t make any real difference to survivability there’s no force driving it to be selected away from, it might eventually be removed by lots of pure chance events but that’s going to take a huge amount of generations meaning the middle time where there’s junk not yet removed us going to be very long
I don’t know too much about the subject, but maybe this almost 30 year old article can help. There’s more specific examples in the article, but this quote captures the direction:
A pretty deus ex machina approach.
How would the size of this plants genetic code be justified I wonder?
https://en.m.wikipedia.org/wiki/Paris_japonica
There are plenty of plants that execute the exact same functions with code thousands of times smaller.
To say every codon has a purpose is to be ignorant of how evolution works. There are start triplicate pairs and stop triplicate pairs, the regions between stop and start don’t need to have function, even structurally, otherwise why would chromosomes come in different lengths? There was no creator of the genome, there was no efficiency driven outcome, there’s only descent with modification, things just happen to with the way they work, and that’s beautiful in it’s own way.
Again, and I can’t emphasize this enough, this is not my area of study and seems like you have better handling of the subject. But when I read his quote, this part sticks out to me:
Additionally, the article calls into question the role of code and protein production as the only role for DNA.
So there maybe stretches of DNA that don’t participate in protein construction, but still has a role. So I question I idea of centering one type function over another.
@TempermentalAnomaly @morphballganon
Junk dna was junk science from the start for ignoring that evolution often eliminates or reduces useless things, like eyes in cave fish, so there’s little likelihood that there’s useless parts of the genome.
But it doesn’t do that instantly and it does it for good reason, eyes and the sections of the brain using them require energy and are vulnerable to infection so in situations where they don’t provide an advantage they increase the likelihood of death before breeding thus giving any offspring born with less energy devoted to eyes has a small advantage which over s very long time results in them being selected away.
So unless the creatures reach a perfect form for their environment then they’ll always be in the process of changing and have some of the old junk in there. Also if the formerly useful part doesn’t make any real difference to survivability there’s no force driving it to be selected away from, it might eventually be removed by lots of pure chance events but that’s going to take a huge amount of generations meaning the middle time where there’s junk not yet removed us going to be very long
@Meowoem
Agree that genome reduction is the slower process, but it’s part of genome evolution, not only the more “energetically expensive” parts.
“Quantitatively, the evolution of genomes appears to be dominated by reduction and simplification, punctuated by episodes of complexification.”
https://onlinelibrary.wiley.com/doi/10.1002/bies.201300037