Eukaryotes have more freedom? (DNA)

[Eagle9]

As we know, both strands in DNA is complementary to each other, it means that nucleotide sequence in one strand completely defines the sequence in the second strand.

Bacteria has got one, circular chromosome and it contains (almost) only genes. So if there are 100 genes in one strand then bacteria will have some certain (and not the genes with any content) genes in the second strand, right?

So, the circumstance that bacterial chromosome is entirely loaded with genes determines the fact that genetic content of one strand completely determines the content of the second strand and vice versa. In other words, the quality of freedom (of having any desired gene(s)) is very low in bacteria. It can not have any gene, in some way its genome's content is “restricted”. Bacteria is “forced” to have some certain genes (anti-sense) in the second strand and it seems to me the miracle that all these genes are really needed for bacteria! Such organisms do not have “superfluous” genes in spite of the fact that one strand entirely depends on other! Is it coincidence or something more?

But in Eukaryotes the situation is different, human’s DNA is loaded with genes by 2-3 %, the rest is junk (well, at least 90 % or so of DNA is old viruses’ corpses). So, if we take some certain gene on one strand then its opposite strand may not have (on just opposite place relative to this gene) some genetic content (nucleotides will be there of course) and (necessary) gene(s) will be at any other place because there are so many places in Eukaryotes’ DNAs.

Or perhaps Eukaryotes (and particularly human’s) complexity demands and maybe defines the relatively huge size of DNA? The huge size gives organism more freedom and possibility to have any gene.

 

[pinball1970]

As we know, both strands in DNA is complementary to each other, it means that nucleotide sequence in one strand completely defines the sequence in the second strand.

Bacteria has got one, circular chromosome and it contains (almost) only genes. So if there are 100 genes in one strand then bacteria will have some certain (and not the genes with any content) genes in the second strand, right?

So, the circumstance that bacterial chromosome is entirely loaded with genes determines the fact that genetic content of one strand completely determines the content of the second strand and vice versa. In other words, the quality of freedom (of having any desired gene(s)) is very low in bacteria. It can not have any gene, in some way its genome's content is “restricted”. Bacteria is “forced” to have some certain genes (anti-sense) in the second strand and it seems to me the miracle that all these genes are really needed for bacteria! Such organisms do not have “superfluous” genes in spite of the fact that one strand entirely depends on other! Is it coincidence or something more?

But in Eukaryotes the situation is different, human’s DNA is loaded with genes by 2-3 %, the rest is junk (well, at least 90 % or so of DNA is old viruses’ corpses). So, if we take some certain gene on one strand then its opposite strand may not have (on just opposite place relative to this gene) some genetic content (nucleotides will be there of course) and (necessary) gene(s) will be at any other place because there are so many places in Eukaryotes’ DNAs.

Or perhaps Eukaryotes (and particularly human’s) complexity demands and maybe defines the relatively huge size of DNA? The huge size gives organism more freedom and possibility to have any gene.

its not quite as simple as that, hoping yaggg and bill will step in but large genome does not equal large complexity. Check out relative genome size wiki. Also the "junk" ie non coding does not mean it it is totally non functional in terms of regulation

https://en.wikipedia.org/wiki/List_of_organisms_by_chromosome_count

 

[Ygggdrasil]

Bacteria is “forced” to have some certain genes (anti-sense) in the second strand and it seems to me the miracle that all these genes are really needed for bacteria! Such organisms do not have “superfluous” genes in spite of the fact that one strand entirely depends on other! Is it coincidence or something more?

Usually, genes are not overlapping. If one strand encodes a protein, the complementary strand usually is not transcribed or made into protein.

Bacterial genomes are likely compact because DNA replication can sometimes be the rate limiting step in their replication. A compact genome allows the bacteria to reproduce more quickly. For humans, and other large multicellular organisms, their reproduction is not limited by the speed of DNA replication, so there is less selective pressure to maintain small, compact genomes.

Compact genomes may not give bacteria opportunities to evolve new functional sequences from non-functional sequences (as is sometimes seen in plants or animals), but bacteria use a different strategy called horizontal gene transfer, in which they take up DNA from organisms in their surroundings, in order to gain new traits and functions (for example, this is one way in which antibiotic resistance can spread throughout a population of bacteria).