These introns can be regarded as examples of selfish DNA.

Sometimes known as "selfish DNA," they usually carry little information beyond what they need to cruise around the genome.

The idea of selfish DNA was originally inspired by the so-called transposons of bacteria.

Furthermore, some introns represent mobile genetic elements and may be regarded as examples of selfish DNA.

While some transposons may confer benefits on their hosts, most are regarded as selfish DNA parasites.

Since retrons are not mobile, their appearance in diverse bacterial species is not a "selfish DNA" phenomenon.

What is more, it is not always easy to distinguish between some instances of selfish DNA and some types of viruses.

It is unclear whether introns serve some specific function, or whether they are selfish DNA which reproduces itself as a parasite.

Because I-CreI provides for its own propagation while conferring no benefit on its host, it is an example of selfish DNA.

Plasmid stabilising toxin-antitoxin systems have been used as examples of selfish DNA as part of the gene centered view of evolution.

Selfish DNA is a term for sequences of DNA that sensu stricto have two distinct properties:

Since this intron provides for its own replication without conferring any benefit on its host, I-CreI is a form of selfish DNA.

Since they do not encode protein products, they used to be considered "junk DNA" or "selfish DNA," having no apparent function beyond their own replication.

Another theory is that sexual reproduction originated from Selfish DNA that exchange genetic material (that is: copies of their own genome) for their transmission and propagation.

In evolutionary terms, toxin-antitoxin systems can be considered selfish DNA in that the purpose of the systems are to replicate, regardless of whether they benefit the host organism or not.

"They exist because they learned to perpetuate themselves," said Dr. Maxine F. Singer, president of the Carnegie Institution in Washington, who has studied this type of selfish DNA.

A far more likely "origin" of viruses comes from the idea of "selfish DNA" and outlaw replicators breaking away from their genomes (or mobile elements moving into and out of genomes throughout time).

The IncP-1 plasmid group (IncP plasmids in Escherichia coli) of which RK2 is a part has been described as "highly potent, self-transmissible, selfish DNA molecules with a complicated regulatory circuit"

Irrespective of the strict definition of selfish DNA, there is no sharp, definitive boundary between the concepts of selfish DNA and genetically functional DNA.

In his 1976 book The Selfish Gene Richard Dawkins suggested the idea of selfish DNA in reaction to the then fairly new revelation of the large proportion of noncoding DNA in eukaryotic genomes.

If you haven't read "The Selfish Gene" and the "Extended Phenotype" by Richard Dawkins, and/or any of the slew of papers regarding Selfish DNA he cites or that were inspired by his work, I highly recommend it.

The average Nilean has no conception of love save as selfish DNA, no higher aspiration (besides an elevator between Nil and Hell, Nil sports individuals whose workaholic existence leaves them no time to think about alternatives) in life, and no pleasure beyond the cynical moment.

Maybe they are using a chat program to try and seem witty, in hopes that the person they are chatting with will want to spend time with them, so that, ultimately, they have a better chance of getting laid, so that, ultimately, their selfish DNA will get to replicate itself.

Such acts of molecular fecundity are quite rare; otherwise, the human genome would start to sag beneath the burden of too much selfish DNA and try to toss the freeloading elements from its midst And even when reproduction does happen, the newborn sequence usually hops into some innocuous spot along the double helix.