3 ms·
Wrong. It is not called junk DNA out of ignorance but because we know much of it is ancient viral insertion. There is no way to cleanse the genome effectively.
by robwwilliams 5y ago
Wrong. It is not called junk DNA out of ignorance but because we know much of it is ancient viral insertion. There is no way to cleanse the genome effectively.
- sterlind 5y agothere must be some genome-cleaning processes active, surely. otherwise wouldn't the size of all genomes slowly ratchet up in every species, until organisms just can't cope anymore and everything goes extinct? also, do you consider introns to be junk DNA? those didn't evolve from viral insertion (probably?) so though they might end up hosting "junk", presumably they're not all "junk."
- asdff 5y agoThere is a balance to genome size in terms of selection. If you have a smaller genome, mutations are more likely to have an effect, which means faster evolution (good if you are a pathogen for example). There are smaller energy requirements with replicating a smaller genome, and fewer atoms needed from the environment with shorter DNA. There is probably some optimal physical size to the nucleus, which gets larger as there is more DNA inside. Deletions can occur during cell division. A deletion bias is observed over a duplication bias: https://en.wikipedia.org/wiki/Bacterial_genome#Deletional_bias https://en.wikipedia.org/wiki/Bacterial_genome#Deletional_bi...
- swayvil 5y agoYet the trope exists, my fervent friend.