Melanomas: characteristic mutations in non-coding DNA
Only 3% of human DNA actually codes for proteins. For a very long time, geneticists regarded with a mixture of astonishment and contempt the remaining 97%, aflaxing it with the sobriquet "garbage DNA". In recent years, however, some of these non-coding regions have proved indispensable in regulating gene expression. Outside the genetic "production chain," a few discrete sequences monitor and regulate the rate of protein synthesis.
It is here, in these vast molecular expanses neglected by microscopes, that Harvard geneticists have just made an important discovery.
Their work, published January 24, 2013, in the journal Science, focused on the genetic sequencing of 70 cell samples taken from melanomas - a common cancer affecting certain cells of the epidermis and mucous membranes. Failing to discover a new denominator common to all strains, scientists were able to observe with interest that two genetic abnormalities coexisted in 50 of the samples. Two mutations present in the non-coding area of DNA.
Such discoveries are exceptional: while genetic specialists know how to find commonalities between dozens of sequences counting for several million elements, they usually focus their efforts on the 3% "useful" of the Genome.
The discovery of Harvard scientists demonstrates the usefulness of going hunting off these beaten paths. The double mutation observed in 50 of the 70 cancer samples is likely not by chance. Such variations in the regions responsible for regulating the expression of the "code" offer radically new avenues for understanding the processes that govern the appearance of a tumour.
Excited by this discovery, Harvard geneticists subsequently searched for the famous double mutation in the genomes of other types of cancer cells. After examining 150 samples taken from liver and bladder tumours, the pattern was found to be present in 16% of cases.
It is now a question of understanding what regulatory variations are induced by these mutations. It is still too early to determine whether or not these abnormalities may or may not become the target of future treatments. This discovery, on the other hand, opens up huge prospects for exploration, demonstrating the importance of examining the smallest sequences of the genome... even if they were located in what was concerned, until recently, as a huge 'discharge'.
It is here, in these vast molecular expanses neglected by microscopes, that Harvard geneticists have just made an important discovery.
Their work, published January 24, 2013, in the journal Science, focused on the genetic sequencing of 70 cell samples taken from melanomas - a common cancer affecting certain cells of the epidermis and mucous membranes. Failing to discover a new denominator common to all strains, scientists were able to observe with interest that two genetic abnormalities coexisted in 50 of the samples. Two mutations present in the non-coding area of DNA.
Such discoveries are exceptional: while genetic specialists know how to find commonalities between dozens of sequences counting for several million elements, they usually focus their efforts on the 3% "useful" of the Genome.
The discovery of Harvard scientists demonstrates the usefulness of going hunting off these beaten paths. The double mutation observed in 50 of the 70 cancer samples is likely not by chance. Such variations in the regions responsible for regulating the expression of the "code" offer radically new avenues for understanding the processes that govern the appearance of a tumour.
Excited by this discovery, Harvard geneticists subsequently searched for the famous double mutation in the genomes of other types of cancer cells. After examining 150 samples taken from liver and bladder tumours, the pattern was found to be present in 16% of cases.
It is now a question of understanding what regulatory variations are induced by these mutations. It is still too early to determine whether or not these abnormalities may or may not become the target of future treatments. This discovery, on the other hand, opens up huge prospects for exploration, demonstrating the importance of examining the smallest sequences of the genome... even if they were located in what was concerned, until recently, as a huge 'discharge'.