& & & * & * * * * * * * & $ & & * * * * * & ' ' * * & * & * \\ \ $ $ & $PLQRDFLG DWWDFKHGKHUH HQG HQG 6WHP ORRS \ & 9DULDEOHORRS $QWLFRGRQORRS $QWLFRGRQ 'ORRS '+ 'LK\GURXULGLQH 7K\PLGLQH3VHXGRXULGLQH DQG&\WLGLQH Fig. . Holley’s two-dimensional clover leaf model of transfer RNA undergoes polymerisation under oxygen tension causing the change in the shape of the RBC from biconcave to a sickle shaped structure. The effect of point mutation can be understood by the following example.
ABC DEF GHI JKL If we insert a letter O between DEF and GHI the arrangement would be ABC DEF O GH IJK L If we insert OQ at the same place the arrangement would be ABC DEF OQ G HIJ KL The above information shows that insertion or deletion of one or two bases, changes the reading frame from the point of insertions or deletions. Such mutations are referred to as frame shift insertion or deletion mutations. This forms the genetic basis of proof that codon is a triplet and is read in a continuous manner