DNA evolutionary connections
UCSD Study Shows 'Junk' DNA Has Evolutionary Importance: "In the October 20 issue of Nature, Peter Andolfatto, an assistant professor of biology at UCSD, shows that non-coding regions play an important role in maintaining an organism's genetic integrity. In his study of the genes from the fruit fly Drosophila melanogaster, he discovered that these regions are strongly affected by natural selection, the evolutionary process that preferentially leads to the survival of organisms and genes best adapted to the environment."
Intron functions: "Although some introns, such as those in globin genes, appear to be inserted at what are structural domain boundaries in the polypeptide, many intron insertion positions bear no relation to structural or functional domains. The theory that introns serve an evolutionary function in allowing the shuffling of exons is still being debated."
Group II introns: "Some group II introns have a second remarkable property: they encode reverse transcriptase (RT) ORFs and are active mobile elements. Such mobile group II introns can insert into defined sites at high efficiencies (called retrohoming), or can invade unrelated sites at low frequencies (retrotransposition).Group II introns were discovered and first studied in organellar genomes, where they are relatively abundant. However, group II introns are now being found in unexpected numbers in bacterial genomes"
Intron functions: "Although some introns, such as those in globin genes, appear to be inserted at what are structural domain boundaries in the polypeptide, many intron insertion positions bear no relation to structural or functional domains. The theory that introns serve an evolutionary function in allowing the shuffling of exons is still being debated."
Group II introns: "Some group II introns have a second remarkable property: they encode reverse transcriptase (RT) ORFs and are active mobile elements. Such mobile group II introns can insert into defined sites at high efficiencies (called retrohoming), or can invade unrelated sites at low frequencies (retrotransposition).Group II introns were discovered and first studied in organellar genomes, where they are relatively abundant. However, group II introns are now being found in unexpected numbers in bacterial genomes"