Spetsai Summer School

Date:
1979-1980
Reference:
PP/CRI/E/1/28/13
Catalogue details

Licence: In copyright

Credit: Spetsai Summer School. Source: Wellcome Collection.

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    10 SELFISH DNA Why do higher organisms have so much DNA? Much of it appears to do little specific and some organisms, such as lilies and salamanders, have much more than we do. it is suggested that we should approach this problem from the viewpoint of natural selection at the DNA level. Perhaps there are types of DNA — selfish DNA — which contribute little or nothing to the organism's phenotype and yet can spread preferentially around the chromosomes. Some of the implications of this idea will be discussed. References: Doolittle, W. F. and Sapienza, C. Selfish genes, the phenotype paradigm and genome evolution. Nature 284 :601-603 (1980). Orgel, L. E. and Crick, F. H. C. Selfish DNA: the ultimate parasite. Nature 284:604-607 (1980). Manfred Eigen 1) Criteria for determining evolutionary kinship relations Methods have been developed that allow one to determine a) whether an evolutionary process has caused divergent or convergent changes in a sequence distribution, b) the topo logy of divergence, and c) the degree of randomization ob tained via mutational events. Applications to tRNA and immu- noglobulines are discussed. 2) Mechanisms of template instructed polymerization Enzyme-free, enzyme-instructed, template-free and en zyme-template instructed mechanisms are compared. The ana tomy of an enzyme-template instructed mechanism has been determined using Qß-replicase and de novo-synthetized templates. The data yield information on early evolutionary processes. 3) An attempt to reconstruct early evolutionary events from present experimental facts (with Ruthild Winkler-Oswatitsch) We report a comparative study of sequences of tRNA. This molecule appears to be one of the most conservative structures which thus provides information of early evolutionary proces ses. A consistent model of an early four letter code and of the start of translation emerges from these studies.
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