Les variations génétiques et leur régulation : la drosophile a beaucoup à nous apprendre
| Autor: | null Laurençon A, C., de La Roche Saint-André, J Ducau, F Gay, Y Azou, null Bregliano J-C |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Genetics
Mutation Non-Mendelian inheritance media_common.quotation_subject Longevity General Medicine Biology biology.organism_classification medicine.disease_cause General Biochemistry Genetics and Molecular Biology Ageing Drosophilidae Heredity medicine Adaptation Reactivity (psychology) media_common |
| Zdroj: | médecine/sciences. 14:I |
| ISSN: | 1958-5381 0767-0974 |
| DOI: | 10.4267/10608/965 |
| Popis: | Two decades ago, in Drosophila, a peculiar cellular state with unusual hereditary properties has been shown in regulate the frequency of transposition of a LINE-like retrotransposon, called 1 factor. This condition takes place in oocytes of reactive stocks, which are permissive for 1 factor transposition. Among reactive strains, there is a wide range of capacities to mobilize 1 factors, called reactivity levels. Genetic studies show a complex heredity due to a mix of chromosoinal and maternal inheritance. These levels undergo heritable, cumulative and reversible changes upon the effect of ageing and of some environmental factors. Reactivity level of females decreases as they get older; this decrease is transmitted to their daughters and can be cumulated over generations. This effect is always reversible if young mothers are used again to recover progeny. The recent work reviewed in this article shows that reactivity levels are enhanced by genotoxic agents, with cumulative and reversible pattern, and are rightly related to repair-recombination efficiencies in oocytes. Gametes from weakly reactive females exhibit more chromosome losses after irradiation than gametes from strong reactive mothers. Conversely, the latter exhibit a higher frequency, of recessive lethal mutations. Recombination frequency is also correlated with reactivity levels although in a more complex way. Life-span of progenies undergo changes which closely parallel those of reactivity level, including cumulative and reversible effect. These data lead us to postulate the existence of a repair-recombination system which activity depends on maternal age and is modulated by environmental conditions. This system has been denoted VAMOS for variability modulation system, Some potential implications, especially for adaptation and longevity are discussed. |
| Databáze: | OpenAIRE |
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