n biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.
Mutations result from errors during DNA replication or other types of damage to DNA (such as may be caused by exposure to radiation or carcinogens), which then may undergo error-prone repair (especially microhomology-mediated end joining[1]), or cause an error during other forms of repair,[2][3] or else may cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements.[4][5][6] Mutations may or may not produce discernible changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity.
The genomes of RNA viruses are based on RNA rather than DNA. The RNA viral genome can be double stranded (as in DNA) or single stranded. In some of these viruses (such as the single stranded human immunodeficiency virus) replication occurs quickly and there are no mechanisms to check the genome for accuracy. This error-prone process often results in mutations.
Mutation can result in many different types of change in sequences. Mutations in genes can either have no effect, alter the product of a gene, or prevent the gene from functioning properly or completely. Mutations can also occur in nongenic regions. One study on genetic variations between different species of Drosophila suggests that, if a mutation changes a protein produced by a gene, the result is likely to be harmful, with an estimated 70 percent of amino acid polymorphisms that have damaging effects, and the remainder being either neutral or marginally beneficial.[7] Due to the damaging effects that mutations can have on genes, organisms have mechanisms such as DNA repair to prevent or correct mutations by reverting the mutated sequence back to its original state.[4]=wiki link
Researchers have diagnosed a dinosaur with ‘severe’ arthritis - 70 million years after its death.
Scientists led by a researcher from the University of Manchester analysed a fossilised elbow joint from a hadrosaur type of dinosaur and concluded it must have endured considerable suffering before it died.
It’s believed to be the first ever recorded account of septic arthritis in dinosaurs.
Hadrosaurs were plant-eating, duck-billed dinosaurs common in parts of Europe, Asia, and North America and ranged in size from 10ft to 40ft long.
There are many different types of named dinosaur within the family.-
Scientists have discovered a tribe of modern-day hunter gatherers smoked cannabis to ward off parasites - suggesting ancient humans may also have had a taste for the high life.
The Aka people are a pygmy tribe from the Congo Basin, living a life of foraging which is little different from our ancestors.
But more than half of the men have a cannabis habit which would put Snoop Doggy Dogg to shame.
"In the same way we have a taste for salt, we might have a taste for psychoactive plant toxins, because these things kill parasites," said Dr. Edward Hagen, who published a report on his research in the American Journal of Human Biology.
He found tribespeople who used cannabis had a lower rate of infection from parasitic worms, suggesting they "unconsciously" used the drug medicinally-