Genome complexity: Plant DNA discoveries (Introduction)

by David Turell , Thursday, January 01, 2015, 14:42 (3615 days ago) @ Balance_Maintained

The largest DNAs of all are found here. Horizontal transfer, natural hybridization, high mutation rates, and much more. Interesting read:-http://www.the-scientist.com/?articles.view/articleNo/38729/title/Genomes-Gone-Wild/-"In the last two years, researchers have stumbled upon some “mind-blowing” phenomena in plant genomics, including genomes so strange that “we didn't think [they] could be like that,” says R. Keith Slotkin, a geneticist at Ohio State University. Examples include the peaceful coexistence of two different genomes in a single nucleus and the willy-nilly way plants swap genes among species. And just as with Hooke's, Brown's, and Mendel's fundamental discoveries in plant biology, the bizarre behavior of plant genomes often applies to animals as well."-And the junk issue:-"Two years later, Victor Albert at the University of Buffalo decided to investigate a group of plant cells with nuclei that looked quite different: they appeared to harbor especially tiny genomes. When Albert and colleague Luis Herrera-Estrella sequenced the genome of Utricularia gibba, a bladderwort that forms free-floating mats with hidden underwater bladders that suck in unsuspecting prey, they found that it has one of the smallest genomes ever to be sequenced from a plant—just 82 million base pairs. Even more interesting, the genome is small not because it has fewer genes than other plants. In fact, it has more genes than grapes, papaya, or Arabidopsis. Rather, 97 percent of the plant's genome is protein-coding genes and gene regulatory regions, with only 3 percent having no known function—what scientists often call “junk” DNA.2 That's the complete opposite of the human genome, which is made up of 98 percent junk and 2 percent protein-coding genes.-"“The implications are that you can make a perfectly good complex, multicellular plant with a gigantic genome or a tiny genome,” says Albert. “You probably need approximately the same number of genes, but the ‘junk' or lack of ‘junk' probably doesn't matter much, if it even matters at all.”"