title: [Problems of variability in weightlessness].
abstract: The genetic (cytogenetic) effects of microgravity have been under study for about 30 years. This line of research developed through three periods. Initially, biologists raised the question whether microgravity may act as a lethal factor or a strong mutagen. Many flight experiments gave a negative answer to it. The major goal of the second period was to identify the effects of microgravity at the chromosomal and cellular levels. Such effects, statistically significant although small in value, were detected in Tradescantia paludosa and Drosophila melanogaster microspores. These findings were confirmed by American and--later--by European investigators. The third period addresses the entire problem of variability in microgravity. This approach can be implemented on the basis of a comprehensive program of research that will include experiments at different levels: from the gene to the population level. The basic objective of the program is to clarify the role of the genetic apparatus in the adaptation of living systems to microgravity and, consequently, to determine the role of gravity in the evolution of life on the Earth.
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005786:Gene Expression Regulation; D014644:Genetic Variation; D006801:Humans; D009154:Mutation; D013026:Space Flight; D014893:Weightlessness
vernacular_title: Problemy izmenchivosti v nevesomosti.