Daily Archives: March 27, 2014

A new international study has revealed how genetics could explain why different environmental exposures can trigger the onset of different forms of rheumatoid arthritis.

A team at the Arthritis Research UK Centre for Genetics and Genomics at The University of Manchester, part of a large international consortium involving scientists from across 15 academic institutions, believe their findings could have important implications for the way that rheumatoid arthritis is diagnosed and treated.

Publishing their findings in the journal American Journal of Human Genetics, they say that more accurate clinical testing is now needed to better identify the less-well understood type of rheumatoid arthritis and to prevent it being misdiagnosed.

Rheumatoid arthritis is a serious inflammatory form of arthritis, affecting almost 400,000 people in the UK, which causes painful, swollen joints, and in severe cases, considerable disability. It is known to have strong genetic and environmental components.

It was already known that a proportion of rheumatoid arthritis patients test positive for autoantibodies, whilst about 30% remain sero-negative. In this study, the researchers have better defined the genetic distinction between these two disease subtypes: sero-positive and sero-negative rheumatoid arthritis.

They have now established that different genetic variants of a protein that plays a vital role in how the body's immune system fights infection are associated with the two forms of rheumatoid arthritis. This provides clues to the theory that exposure to different infectious agents, such as bacteria or viruses, trigger the different forms of rheumatoid arthritis in susceptible individuals. Sero-negative rheumatoid is less well understood than sero-positive, and patients who have this type of arthritis can be misdiagnosed, leading to inappropriate treatment.

Dr Steve Eyre from the genetics and genomics centre in Manchester commented: "We recognise that rheumatoid arthritis is a complex disease that can have variable presentation and outcomes for different people, in particular in the way they respond to treatment. These findings add to our ability to genetically define subtypes of rheumatoid arthritis, which is an important step towards selecting the best treatment for each patient."

Centre director Professor Jane Worthington added: "Now that we have established a genetic basis for these two types of rheumatoid arthritis, we hope it will lead to patients receiving a swifter, accurate diagnosis and more appropriate, targeted treatment. These findings have opened the door to a better understanding of sero-negative rheumatoid arthritis."

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The above story is based on materials provided by Manchester University. Note: Materials may be edited for content and length.

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Genetics can explain why infections can trigger onset of different types of rheumatoid arthritis

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To better understand why and how disease works in the human body, scientists are increasingly turning to genetics for answers. Now, a large international team has made the first detailed map of how genes work within the cells and tissues of the human body.

They have published their research in a series of papers, two of which appear in the journal Nature.

The findings, which describe the intricate networks that oversee gene activity, could help identify the main genes involved in disease.

Calling their atlas a "major advance," Prof. Winston Hide, study author from Harvard School of Public Health, says their findings will better their ability to "understand the causes of disease across the body."

The atlas is the result of years of collaboration between 250 experts from over 20 countries. They were all part of the FANTOM 5 project, which stands for Functional Annotation of the Mammalian Genome.

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Researchers produce first comprehensive atlas of human genes

12 hours ago

(Phys.org) Genetics provides stunning new answers to the question of human evolution, according to Auckland cancer researcher, Dr Graeme Finlay.

Genetic markers that are used to follow the development of populations of cells have exactly the same character as those that track the development of species, says Dr Finlay who has just published a book on genetics and human evolution.

His book, 'Human Evolution: Genes, Genealogies and Phylogenies', was published by Cambridge University Press late last year.

Dr Finlay is senior lecturer in Scientific Pathology at the Department of Molecular Medicine and Pathology, and an Honorary Senior Research Fellow at the Auckland Cancer Society Research Centre, in the University of Auckland.

"Controversy over human evolution remains widespread, but the human genome project and genetic sequencing of many other species have provided myriad precise and unambiguous genetic markers that establish our evolutionary relationships with other mammals," says Dr Finlay.

This book identifies and explains these identifiable, rare and complex markers including endogenous retroviruses, genome-modifying transposable elements, gene-disabling mutations, segmental duplications and gene-enabling mutations.

These new genetic tools also provide fascinating insights into when and how many features of human biology arose: from aspects of placental structure, vitamin C dependence and trichromatic vision, to tendencies to gout, cardiovascular disease and cancer.

The book brings together a decade's worth of research and ties it together to provide an overwhelming argument for the mammalian ancestry of the human species.

Dr Finlay says he hopes the book will be of interest to professional scientists, undergraduate and college students in both the biological and biomedical sciences, and to anyone including theologians concerned with the scientific evidences for evolution.

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Genetic markers provide unprecedented primate link in human evolution

22 hours ago

A presentation at Genetics Society of America's Drosophila Research Conference builds the case that de novo genes derived from ancestral non-coding DNA can spread through a species.

Earlier this year, researchers in David J. Begun, Ph.D.'s lab at UC Davis reported that they had uncovered 142 de novo genes that originated in the ancestral non-coding DNA sequences and are segregating in Drosophila melanogaster populations.

Dr. Begun and postdoctoral scientist Li Zhao, Ph.D., identified de novo genes by comparing the RNA transcripts of the testes of several wild-derived strains of D. melanogaster to the standard reference genome for this fly species and to the RNA transcripts and genomes of two other Drosophila species.

Their results suggested that these genes may play an important role in Drosophila male reproduction. The UC Davis scientists, who were the first to investigate whether de novo genes spread through a species, next turned their attention to females.

They conducted a systematic search for de novo genes that were expressed in female Drosophila flies and determined that these genes appear to derive primarily from ancestral intergenic sequences, which is similar to the case for male-biased de novo genes.

At the GSA Drosophila Research Conference, Dr. Zhao will report about the female-expressed de novo genes. The population genetics and role of selection on these genes will also be discussed.

Explore further: New genes spring and spread from non-coding DNA

More information: Abstract: "Female-expressed de novo genes in Drosophila." Li Zhao, David J. Begun. abstracts.genetics-gsa.org/cgi-bin/dros14s/showdetail.pl?absno=14531505

Provided by Genetics Society of America

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Female fly genomes also populated with de novo genes derived from ancestral sequences