Friday, July 28, 2006
New research has provided evidence for 'environmental inheritance', a radical theory of transgenerational genetic adaptation proposed by Professor Marcus Pembrey of the Institute of Child Health, UCL in the mid 1990's
The latest evidence challenges accepted thinking on genetic inheritance, suggesting that historic events can contribute to some common modern illnesses.
The research, published by the Children of the 90s study based at the University of Bristol in collaboration with Umea University, Sweden, could have far-reaching implications for our understanding of modern health epidemics - such as obesity or cardiovascular disease.
Conventionally scientists believe that how we develop as adults depends on two factors - the genes (DNA) we inherit from our parents, and the environmental influences, such as diet, lifestyle, exposure to pollution from conception onwards.
Professor Marcus Pembrey, who is also head of Genetics at Children of the 90s, says that over the long term, the process of Darwinian evolution by random errors in DNA followed by natural selection ensures that the human race adapts to changes in our environment. But it takes very many generations.
Now there is evidence for another mechanism which no-one had considered... some of the father's own experiences in his childhood are captured in some way by his sperm, so affecting the genes that he bequeaths to his descendants.
[NB Although this is only a press release I've got at least one relevant technical paper which I'll be posting soon - when I find it!]
14th December 2005
technorati tags: research, theory, adaptation, marcus+pembrey, obesity, cardiovascular, disease, genes, dna, parents, diet, lifestyle, pollution, genetics, darwinian, evolution, natural+selection, environment, mechanism, sperm
Tuesday, July 25, 2006
[After clicking on the above link, click on "Full Text"]
Evolution: Bacterial Mutation in Stationary Phase
Paul Sniegowski, Current Biology, March '04
Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
A recent study indicates that the genomic mutation rate of the gut bacterium Escherichia coli is substantially higher in nongrowing than growing cultures. These findings are important in the light of the ongoing controversy over the generality and robustness of stationary phase mutagenesis and its evolutionary implications.
Article Outline begins:
The genomic mutation rate is a fundamental evolutionary parameter of any population, determining the rate of influx of new deleterious and beneficial alleles. Because most mutations are likely to be harmful to fitness, DNA repair and proofreading systems have probably evolved so as to minimize rates of mutation. Even the microbial extremophiles that normally inhabit harsh and potentially mutagenic environments seem to have low genomic mutation rates, suggesting that selection almost always puts a premium on the faithful maintenance and transmission of genetic information. Nonetheless, geneticists have long known that some environmental extremes can elevate mutation rates; indeed, this is the basis for the use of DNA damaging agents to induce mutations for study.
[email if the link stops working]
Sunday, July 23, 2006
The Changing Concept of Epigenetics
Annals of the New York Academy of Sciences, 981: 82-96. (2002)
Eva Jablonka and Marion J. Lamb
Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University, Tel Aviv 69978, Israel
ABSTRACT: We discuss the changing use of epigenetics, a term coined by Conrad Waddington in the 1940s, and how the epigenetic approach to development differs from the genetic approach. Originally, epigenetics referred to the study of the way genes and their products bring the phenotype into being. Today, it is primarily concerned with the mechanisms through which cells become committed to a particular form or function and through which that functional or structural state is then transmitted in cell lineages. We argue that modern epigenetics is important not only because it has practical significance for medicine, agriculture, and species conservation, but also because it has implications for the way in which we should view heredity and evolution. In particular, recognizing that there are epigenetic inheritance systems through which non-DNA variations can be transmitted in cell and organismal lineages broadens the concept of heredity and challenges the widely accepted gene-centered neo-Darwinian version of Darwinism.
technorati tags: epigenetics, new+york, academy, jablonka, lamb, cohn, institute, genetic, genes, phenotype, cells, medicine, agriculture, heredity, evolution, inheritance, dna, darwinian, darwinism, tel+aviv