The size of the genome (which can be said to be the amount of DNA in an organism's genes) varies enormously from one species to another. The smallest size, for viruses, varies from 2 thousand base-pairs to over a million.Humans have about 3 billion (forming around 19,000 genes) - but some plants have more than 10 times as much. The lack of correlation between the apparent complexity of an organism and its genome size is called the "G-value paradox".What gives /sci/?
>>15284090polyploidy, redundant copies of chromosomes
>>15284093What do the number of chromosomes an organism posseses have to do with it? It's talking about genome size.
>>15284132ok then junk DNA
>>15284138Junk DNA? Isn't this moniker sort of obsolete and outdated in light of contemporary research regarding non-coding regions?At minimum, ENCODE showed that at least 80% of the genome is transcribed, and newer research estimates this figure to ultimately be much higher.And just from a logical perspective, wouldn't it make sense to conclude that the primary source contributing to complexity isn't the genome, but rather the once dubbed "junk DNA".This seems quite intuitive considering the recognized lack of correlation between genome size and complexity.
If I remember correctly some ugly fish is the mammal with the biggest genome. Guess that means he's the most evolved.
There is no such thing as being more or less evolved
>>15284157how much of the junk DNA that gets transcribed get translated into working proteins though?
>>15284200Proteins? None, that's what non-coding means.How much of that contributes to the regulation and expression of the genome? That's a matter of ongoing research, but functionality of an RNA isn't measured by whether or not it is translated, we know this not to be the case. E.g. alternative splicing We know that non-coding RNAs play a critical multi fauceted role in genomic regulation, but more importantly, these functionalities and RNA types are increasingly being discovered at rapid pace.I see no reason for this trend of discovery to stop, do you?
>>15284248no but I didn't know that, how can non-coding RNAs regulate gene expression? enhancer proteins and epigenetics are the only ways iirc
>>15284289Too many ways to name.But here is one example, microRNAs.microRNA controls gene expression mainly by binding with messenger RNA (mRNA) in the cell cytoplasm. Instead of being translated quickly into a protein, the marked mRNA will be either destroyed and its components recycled, or it will be preserved and translated later.Anything that regulates / modifies genomic expression would fall under the umbrella of epigenetics.
>>15284413Thanks, but that doesn't have anything to do with the original post is about.Which in case you've forgotten, is the lack of correlation between organismal complexity and genome size.
>>15284090Complexity doesn't mean apparent complexity. An organism can have the need to perform very specific functions that need specialized genes and the respective machinery it builds. However, that task isn't of concern for an organism who doesn't live in the same environment performing the same tasks as the first organism. So an organism may be complex as in it perform novel processes inside it's cells, but that doesn't manifest in visible features, instead being observable by the organism surviving in conditions where it shouldn't. Which conditions are these can be many, such as thriving with certain nutrients being present at lower concentrations, or being able to better withstand sudden temperature shifts in it's environment. These conditions can be very specific and only seem unusual if you had a population of the same organism without the gene which you could compare to, as they might need those additional genes to compensate for shortcomings due to other prior genes that had a net positive effect on their survival and as such were not worth abandoning.Another effect to take into account is emergent properties. Certain organisms might be more efficient with their genome size because they have certain genes that, when combine, can provide the same services as specialized genes. For example, you could have a gene dedicating to coding for a protein that, in the presence of a certain substance, binds to some receptor. However, a creature with a more efficient genome could have a protein that performs that function to an acceptable standard when in the presence of a second protein, even if those two proteins by themselves are specialized for performing a different role. So the second organism simply increases it's expression of both proteins when signaled to do so, instead of accessing a specific genome for a specific protein for that task.Do note that I'm not a biologist, so none of the examples I gave are referring to a specific, real world process.
>>15284090>The lack of correlation between the apparent complexity of an organism and its genome size is called the "G-value paradox".https://youtu.be/5ChRM4CEWygThe other part of the equation?
>>15285763My comment ended up being to long, but to put it short: there are many ways to crack an egg, and different organisms are cooking different meals for different parties. Complexity can be hard to observe, and not all complexity is expressed by the amount of information directly present on the DNA, as proteins are extremely complex and the complexity in their behaviour cannot be inferred simply by how long it's coding sequence is.The real tl;dr is that proteins are near magic and a smaller total of them doesn't mean less capacity for an organism, as having a few crucial proteins can be game changing. And also, complexity is hard to measure.
