Tag Archives: DNA

A “Jumping Gene’s” Preferred Targets May Influence Genome Evolution

By Guest PostSeptember 10, 2011Scienceallan spradling, baylor college of medicine, cell, chromosomes, DNA, dna duplication, drosophila, drosophila melanogaster, drosophila transposons, fruit fly, gene disruption project, gene function, genetic blueprint, genome duplication cycle, genome structure, hugo bellen, human cell, human genome, jumping genes, minos, model organisms, p element, piggybac, rogerhoskins, transposons

Baltimore, MD — The human genome shares several peculiarities with the DNA of just about every other plant and animal. Our genetic blueprint contains numerous entities known as transposons, or “jumping genes,” which have the ability to move from place to place on the chromosomes within a cell.

An astounding 50% of human DNA comprises both active transposon elements and the decaying remains of former transposons that were active thousands to millions of years ago before becoming damaged and immobile. If all of this mobile and formerly mobile DNA were not mysterious enough, every time a plant, animal or human cell prepares to divide, the chromosome regions richest in transposon-derived sequences, even elements long deceased, are among the last to duplicate. The reason for their delayed duplication, if there is one, has eluded biologists for more than 50 years. (more…)

Ancient Humans Were Mixing it Up

By Guest PostSeptember 7, 2011Scienceafrica, archaic hominin forms, august woerner, central africa, chromosome, contemporary african populations, DNA, eurasia, fernando mendez, fossil, fossil specimens, genome, homo, homo sapiens, hybridization, jeffrey wall, joseph watkins, michael hammer, modern humans, molecular biology, morphologically diverged neighbors, neanderthal bones, neanderthals, sub saharan africans

*Anatomically modern humans interbred with more archaic hominin forms even before they migrated out of Africa, a UA-led team of researchers has found.*

It is now widely accepted that anatomically modern humans of the species Homo sapiens originated in Africa and eventually spread throughout the world. Ancient DNA recovered from fossil Neanderthal bones suggests they interbred with more archaic hominin forms once they had left their evolutionary cradle for the cooler climates of Eurasia, but whether they exchanged genetic material with other, now extinct archaic hominin varieties in Africa remained unclear.

In a paper published in the Proceedings of the National Academy of Sciences, or PNAS, a team led by Michael Hammer, an associate professor and research scientist with the UA’s Arizona Research Labs, provides evidence that anatomically modern humans were not so unique that they remained separate. (more…)

Research Reveals How Butterflies Copy Their Neighbours to Fool Birds

By Guest PostAugust 13, 2011Natureamazonian species, bates and darwin, butterfly, chromosomal region, chromosome, cnrs, DNA, eaten by birds, evolutionary thinkers, heliconius numata, liverpool university, mathieu joron, melinaea, müllerian mimicry, muséum national d'histoire naturelle, neighbouring species, non mimetic patterns, Paris, patterns of warning colouration, peppered moth, rainforest, richard ffrench constant, supergene, university of exeter, wallace, wing colour patterns, wing patterns

The mystery of how a butterfly has changed its wing patterns to mimic neighbouring species and avoid being eaten by birds has been solved by a team of scientists.

The study is published in the journal Nature. (more…)

Life Scientists Use Novel Technique to Produce Genetic Map for African Americans

By Guest PostJuly 23, 2011Scienceafrican american, african american dna, african ancestry, african and european ancestry, african caribbeans, ancestry, bioinformatics, biological process, cag, chicago asthma genetics, chromosome, collaborative study on the genetics of asthma, csga, daniel wegmann, david reich, discover genes, disease mapping, DNA, european populations, european rate, genestar, genetic diseases in african americans, genetic map, genetic network of arteriopathy, genetic research on asthma in the africa diaspora, genetic study of atheroscleoris risk, genoa, genome, graad, high resolution genetic maps, john novembre, journal nature genetics, nelson freimer, recombination, saarp, scales of the genome, searle foundation, severe asthma research program, simon myers, snp typing for association with multiple phenotypes from existing epidemiological data, stampeed, ucla life scientists

UCLA life scientists and colleagues have produced one of the first high-resolution genetic maps for African American populations. A genetic map reveals the precise locations across the genome where DNA from a person’s father and mother have been stitched together through a biological process called “recombination.” This process results in new genetic combinations that are then passed on to the person’s children.

The new map will help disease geneticists working to map genetic diseases in African Americans because it provides a more accurate understanding of recombination rates among that population, said the senior author of the research, John Novembre, a UCLA assistant professor of ecology and evolutionary biology and of bioinformatics. The map could help scientists learn the roots of these diseases and discover genes that play a key role in them. (more…)

UF Researchers Help Pinpoint Key Events in Ancient Plant Evolution

By Guest PostApril 14, 2011Scienceancient genome duplication, angiosperms, big bangs, cucumber plants, DNA, doug soltis, evolution of seed and flowering plants, flowering plants, genes, genomes, grape, jonathan wendel, modern genome complexity, organisms humans, pam soltis, papaya, poplar, rice, signal, university of florida, water lily

GAINESVILLE, Fla. — Researchers from the University of Florida and six other institutions have unlocked some of the key foundations for the evolution of seed and flowering plants.

The study, to be published online Sunday in Nature, is the first to identify the occurrence of ancient genome duplication events and show the genomes of seed and flowering plants duplicated before each group of plants diversified. It introduces new factors for further molecular research on the organisms humans depend on for food, clothing and shelter. (more…)

Getting a Tighter Grip on Cell Division

By Guest PostNovember 25, 2010Sciencebungo akiyoshi, cell, cell division, chinese handcuff, chromosomes, DNA, genetic information, kinetochore, microtubule, sue biggins

*Molecular “machine” responsible for pulling chromosome copies apart is isolated and seen in action outside the cell*

The dance of cell division is carefully choreographed and has little room for error. Paired genetic information is lined up in the middle of the cell in the form of chromosomes. The chromosomes must then be carefully pulled apart so that the resulting daughter cells each have an identical copy of the mother cell’s DNA. (more…)

UCLA Researchers Identify Molecular Program for Brain Repair Following Stroke

By Guest PostNovember 13, 20101 commentHealth, Scienceadult brain, atrx, axons, brain, brain stroke, carmichael, cells, DNA, drug, gene, giovanni coppola, healing process, molecular cascade, mouse, neurons, peri infarct tissue, s thomas carmichael, stroke

Mouse Stroke. An MRI of a mouse brain after stroke. The mouse section has been stained to show cell bodies. Image credit: University of California

A stroke wreaks havoc in the brain, destroying its cells and the connections between them. Depending on its severity and location, a stroke can impact someone’s life forever, affecting motor activity, speech, memories, and more.

The brain makes an attempt to rally by itself, sprouting a few new connections, called axons, that reconnect some areas of the brain. But the process is weak, and the older the brain, the poorer the repair. Still, understanding the cascade of molecular events that drive even this weak attempt could lead to developing drugs to boost and accelerate this healing process.

Now researchers at UCLA have achieved a promising first step. Reporting in the current online edition of the journal Nature Neuroscience, senior author Dr. S. Thomas Carmichael, a UCLA associate professor of neurology, and colleagues have, for the first time, identified in the mouse the molecular cascade that drives the process of reconnection or sprouting in the adult brain after stroke. (more…)

New 3-D Model of RNA ‘Core Domain’ of Enzyme Telomerase May Offer Clues to Cancer, Aging

By Guest PostNovember 6, 2010Health, Scienceaging, cancer, cells, chromosomes, DNA, dna damage, enzyme, helical extension, juli feigon, medicine, nmr, nobel prize, nuclear magnetic resonance, physiology, proteins, pseudoknot, qi zhang, rna, spectroscopy, telomerase, telomeres, virus

A model representation of telomerase's RNA "core domain," determined by Juli Feigon, Qi Zhang and colleagues in Feigon's UCLA laboratory. Image credit: Juli Feigon, UCLA Chemistry and Biochemistry/PNAS

Telomerase is an enzyme that maintains the DNA at the ends of our chromosomes, known as telomeres. In the absence of telomerase activity, every time our cells divide, our telomeres get shorter. This is part of the natural aging process, as most cells in the human body do not have much active telomerase. Eventually, these DNA-containing telomeres, which act as protective caps at the ends of chromosomes, become so short that the cells die.

But in some cells, such as cancer cells, telomerase, which is composed of RNA and proteins, is highly active and adds telomere DNA, preventing telomere shortening and extending the life of the cell.

UCLA biochemists have now produced a three-dimensional structural model of the RNA “core domain” of the telomerase enzyme. Because telomerase plays a surprisingly important role in cancer and aging, understanding its structure could lead to new approaches for treating disease, the researchers say. (more…)