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> but also lock in a fair amount of legacy details that would be hard to evolve out due to the amount of dependencies on them (everything in biology is tightly

by tomxor 8y ago

> but also lock in a fair amount of legacy details that would be hard to evolve out due to the amount of dependencies on them (everything in biology is tightly related, even modular systems leak). I remember visiting a clone of the Encephalartos_woodii (AKA "the loneliest plant in the world") which is thought to have evolved into a genetic dead end due to it's massive genome which is said to be 20 times the size of the human genome... I wondered if this was due to some kind of dependence, which sounds a lot like what you are saying?

dekhn 8y ago
it's not clear what the plants that have super-large genomes are doing. Some of them are perfectly capable and show little to no negative issues associated with their genomes. I think the case you're describing, there was just a large full-genome duplication that was tolerated (somehow the gene regulation still works and the appropriate amount of protein products are expressed, etc). What I meant more is that most enzymes work in regulated webs and you can't easily tweak one part of the web without having knock-on effects on all the other genes. Nature seems to handle this via gene duplication- once a gene is duplicated, it seems like one can carry on the original function for its dependents, while another is freer to evolve new functions. Sorry I don't have a better explanation for this- to really talk about this you kind of need to have a huge background and know a ton of biology and have read all the debates from all the players about fitness and evolution and even then, nobody really has good answers for this.
- tomxor 8y ago
  > Nature seems to handle this via gene duplication- once a gene is duplicated, it seems like one can carry on the original function for its dependents, while another is freer to evolve new functions. I think this is a pretty decent explanation for the layman :) I might not appreciate all of the technical details but it's easy to imagine why this would work conceptually. There are plenty of computery analogies, like running a legacy program in production while developing an experimental one.

by tomxor 8y ago

dekhn 8y ago

it's not clear what the plants that have super-large genomes are doing. Some of them are perfectly capable and show little to no negative issues associated with their genomes. I think the case you're describing, there was just a large full-genome duplication that was tolerated (somehow the gene regulation still works and the appropriate amount of protein products are expressed, etc). What I meant more is that most enzymes work in regulated webs and you can't easily tweak one part of the web without having knock-on effects on all the other genes. Nature seems to handle this via gene duplication- once a gene is duplicated, it seems like one can carry on the original function for its dependents, while another is freer to evolve new functions. Sorry I don't have a better explanation for this- to really talk about this you kind of need to have a huge background and know a ton of biology and have read all the debates from all the players about fitness and evolution and even then, nobody really has good answers for this.

tomxor 8y ago
> Nature seems to handle this via gene duplication- once a gene is duplicated, it seems like one can carry on the original function for its dependents, while another is freer to evolve new functions. I think this is a pretty decent explanation for the layman :) I might not appreciate all of the technical details but it's easy to imagine why this would work conceptually. There are plenty of computery analogies, like running a legacy program in production while developing an experimental one.