R Holliday

..There have also been innumerable studies on the abnormal de novo methylation and silencing of tumour suppressor genes in cancer cells...

..The human epigenome project will unravel the pattern of DNA methylation in different tissues, and will this determine whether the regulation of gene expression is at the level of DNA or chromatin, or both...

..The stochastic feature of the theory is the probability of the loss of the last uncommitted cells or the youngest committed cells. These cells have the longest lifespan and will give rise to the final population...

..Much is already known about the de novo methylation of tumor suppressor genes in cancer cells, but the significance of epigenetic defects during ageing and in some familial diseases remains to be determined...

..Fluctuating environments are more likely to promote the evolution of small short-lived species with high fecundity...

..Hibernation is a natural form of calorie restriction, and in some cases may lengthen lifespan...

..We can therefore conclude that this evolved design is intrinsically related to the fact of aging. This in turn means that aging cannot be reversed, although it may be modulated, as, for example, by calorie restriction...

..Meiosis and sex could have arisen in an asexually reproducing species and formed a clonal population...

..The strength and success of molecular biology came from the many interactions between geneticists, physicists, chemists and biochemists. It was also characterized by a powerful combination of theoretical and experimental approaches...

..The anti-aging movement proposes in a few decades to reverse what has been the result of millions of years of evolution...

..The hypothesis that DNA methylation has a role in gene expression in higher organism is now supported by abundant evidence. Direct evidence that gene silencing in mammalian cells is causally related to DNA methylation has been obtained...

..The failure of maintenance is irreversible, although longevity may be modulated under certain circumstances, such as dietary restriction accompanied by a loss of fertility...

..The eventual failure to maintain the integrity of tissues and organs is the end result of the multiple causes of aging...

..Much more recently, the revolution in molecular genetics has been in exploited in several laboratories working with Ustilago maydis, and these have produced some completely new insights into recombination and repair...

..The major aim of such research is to devise procedures to delay or prevent the onset of these diseases...

..In the absence of pyruvate, carnosine is cytotoxic to neoplastic and transformed human and rodent cells. None of these effects are seen with its optical isomer, D-carnosine...

..Religion then became the basis for the moral code, and it provided an assurance of continual survival after death...

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..The major aim of such research is to devise procedures to delay or prevent the onset of these diseases...

..It seems that 5-methyldCMP deaminase can be down-regulated in transformed cells, and this can promote de novo methylation by incorporation of 5-methyldCTP derived from 5-methyldCMP...

..It also has low 5-methyl-dCMP deaminase activity. Another HAM+ strain has high deaminase activity and a very low frequency of gene silencing. The starting strain, CHO K1, has a phenotype intermediate between HAM- and HAM+...

..It is well known that tumour cells are more dependent on glycolysis than normal cells. A reduction of glycolysis intermediates by carnosine may deplete their energy supply, but this effect is totally reversed by pyruvate...

..He was also a practitioner and lover of sports and in his early career was politically active. His successes in life made him an extraordinarily talented man who achieved much as a leader in genetics in the UK and internationally...

..These include the use of a BRCA2 homolog and its modifier Dss1 rather than Rad52 as a mediator of Rad51, the presence of only a single Rad51 paralog, and the absence of Dmc1 and auxiliary meiotic proteins...

..maydis. Evolution of a system enabling the survival of U. maydis under such conditions could be a secondary consequence of adaptation to an environment of continual genotoxic stress encountered in its habitat...

..This inevitably occurred at the same time as man gradually gained more control over his environment, and achieved far more reproductive success than is seen in hunter-gatherers living in a harsh, stressful environment...

..Nevertheless, proteins can chemically modify DNA, and this is now known to have strong effects on gene expression...

..Nevertheless, much more information is required about the effects of DNA-damaging agents in changing DNA methylation and gene activity and also about the role of epimutations in tumor progression...