The accuracy of protein synthesis and its relevance to ageing are discussed by L. E. Orgel. He argues that the accumulation of transcription errors in protein synthesis could contribute to ageing. The accuracy of protein synthesis depends on both the correct genetic specification and the competence of the protein-synthetic apparatus. Errors in transcription can lead to errors in protein sequence, which may affect the function of proteins involved in metabolic processes or genetic information processing. The error frequency in protein synthesis is likely to be low, but if errors accumulate, they could lead to an error catastrophe, where the error frequency becomes so high that vital cellular processes become critically inefficient. Orgel suggests that selection for accurate protein-synthesizing units is necessary to prevent this. However, there is no evidence for such segregation within a single cell. At the cellular or higher level, there must be variation in the accuracy of the protein-synthetic apparatus to allow for selective pressure to eliminate less accurate cells. This would maintain the accuracy of protein synthesis and prevent error catastrophe. Orgel also raises questions about the role of cumulative inaccuracy in protein synthesis in ageing and the protective mechanisms that prevent error catastrophe in higher organisms. He suggests experiments using amino acid analogues to study the effects of errors in protein synthesis. In higher organisms, the situation is more complex due to the presence of dividing and non-dividing cells. The accumulation of transcription errors is likely to be more serious for non-dividing cells, as selection at the cellular level is impossible. The mechanisms of protection or selection in higher organisms are not well understood, but possibilities include selection in the growing embryo or quality control mechanisms that convert certain errors into lethal polypeptides. Orgel concludes that the accumulation of protein transcription errors is not the mechanism of ageing, but rather one possible source of progressive deterioration of cells and cell lines.The accuracy of protein synthesis and its relevance to ageing are discussed by L. E. Orgel. He argues that the accumulation of transcription errors in protein synthesis could contribute to ageing. The accuracy of protein synthesis depends on both the correct genetic specification and the competence of the protein-synthetic apparatus. Errors in transcription can lead to errors in protein sequence, which may affect the function of proteins involved in metabolic processes or genetic information processing. The error frequency in protein synthesis is likely to be low, but if errors accumulate, they could lead to an error catastrophe, where the error frequency becomes so high that vital cellular processes become critically inefficient. Orgel suggests that selection for accurate protein-synthesizing units is necessary to prevent this. However, there is no evidence for such segregation within a single cell. At the cellular or higher level, there must be variation in the accuracy of the protein-synthetic apparatus to allow for selective pressure to eliminate less accurate cells. This would maintain the accuracy of protein synthesis and prevent error catastrophe. Orgel also raises questions about the role of cumulative inaccuracy in protein synthesis in ageing and the protective mechanisms that prevent error catastrophe in higher organisms. He suggests experiments using amino acid analogues to study the effects of errors in protein synthesis. In higher organisms, the situation is more complex due to the presence of dividing and non-dividing cells. The accumulation of transcription errors is likely to be more serious for non-dividing cells, as selection at the cellular level is impossible. The mechanisms of protection or selection in higher organisms are not well understood, but possibilities include selection in the growing embryo or quality control mechanisms that convert certain errors into lethal polypeptides. Orgel concludes that the accumulation of protein transcription errors is not the mechanism of ageing, but rather one possible source of progressive deterioration of cells and cell lines.