150,000 quadruplex DNA sequence motifs found to be non-randomly distributed throughout the genetic material of maize: Scientists uncover four-stranded elements of maize DNA - Dec. 3, 2014 Excerpt: A team led by Florida State University researchers has identified DNA elements in maize that could affect the expression of hundreds or thousands of genes. Maybe they are part of the machinery that allows an organism to turn hundreds of genes off or on,,,, Bass and Carson Andorf,,, began this exploration of the maize genome sequence along with colleagues from FSU, Iowa State and the University of Florida. They wanted to know if certain DNA structures such as the four-strand G-quadruplex (G4) DNA might exist throughout the genetic material of maize. G4 structures are present in genes that regulate cancer and cell division in humans, making it an important focus in scientific research. But, not much is known about them.,,, The general public thinks of DNA as two connected strands known as the double helix. But scientists also discovered over the years that those strands regularly separate so they can replicate the genetic material. That material can also twist into different shapes such as a G-quadruplex. Bass and his colleagues found 150,000 sequence motifs that could theoretically adopt the G4 DNA structure, and they were distributed all over the chromosomes. Further examination showed that they were present in very specific places, as opposed to a random distribution. Given the strategic placement, the G4 is likely to perform some sort of function. Preliminary work showed that many of the genes identified were implicated in responses to energy crises within plant cells.,,, Its a very interesting aspect of DNA, Bass said. And people in the genetics field are very excited about it. phys.org/news/2014-12-scientists-uncover-four-stranded-elements-maize.html Moreover, G-quadruplexes are found to be conserved from bacteria to humans. Which opens the tantalizing possibility that a species specific non-random distribution of quadruplex DNA sequence motifs may be found throughout all of biological life: Another Remarkable DNA Rescuing Machine (Elucidated) -June 4, 2013 Excerpt: Some of these are composed of four strands that form stable structures called G-quadruplexes or G4s, so named because they tend to be rich in guanine. They are not uncommon,,,, ,,there is a machine that can unwind these G4s quickly and efficiently. Called Pif1 helicase, it is conserved from bacteria to humans.,,, Pif1 is “highly conserved, from bacteria to humans,” evolutionnews.org/2013/06/another_remarka072811.html
Posted on: Wed, 03 Dec 2014 12:16:19 +0000