∞ generated and posted on 2016.02.06 ∞
String of nucleic acid bases that together encode the transcription of a single piece of RNA.
Genes have to attract the binding of RNA polymerase, have a location where transcription begins, are transcribed linearly from approximately one end of the gene to the other, and then signal the RNA polymerase to stop transcribing.
The result of this process the production of a single piece or RNA, a , has a reasonably well-defined start (), and reasonably well-defined stop (), and a well-defined sequence of nucleotides in between.(Try not to be confused by the use of "start" and "stop" in the previous sentence as these do not refer to start and stop codons, which are an aspect of translation rather than the process of transcription.)
Genes can range in length from any tens of nucleotides to many thousands of nucleotides. Only one strand of DNA making up a double helix typically encodes an individual gene, the template strand, with the other strand typically serving solely as its complement, that is, simply the other half of the double helix.
Video (Describes processes for origin of new genes, though surprisingly ignores horizontal gene transfer and also muddies the presentation by dragging an anti-creationism stance into the arguments; note that from 5:35 to 5:46 an image of phage plaques is presented that turns out to be from a 2008 publication of mine ☺)