Sunday, February 15, 2009

GENETIC MUTATIONS
A mutation is any permanant change in the DNA sequence. Most mutations are recognised because the phenotype, that is the characteristics displayed by an organism, have changed. There are different types of mutation. Mutations are rare events occurring at a rate of 1 in every 50 million bases added to the nucleotide chain. The rate of Mutation is 1 in10x7 cells to 1 in 10x12 cells. Most of the changes that happen are quickly repaired by our very efficient and accurate DNA repair system. But this repair mechanism is not foolproof. Failure to repair all mutations has led to the introduction of some mutations that have made organisms fitter and better able to adapt to their environments. However, many mutations have detrimental effects for an organism and it is these mutations that are the basis of many human genetic disorders and disease.
Please Click on the link below and Right Click and "Save"
http://www.cumc.columbia.edu/dept/ps/2007/mid/2006/MID2.pdf
Right Click and "Save" For FRANCOIS JACOB's Genetics of the bacterial cell NobelLecture,Decemberll, 1965