The other is that a minor difference--a single nucleotide change, or "point mutation
'--in the DNA sequence turns a normal gene into a potent cell-transforming agent.
These data indicated that the heterozygous point mutation
we identified in GBA gene led to a GCase mutation that reduced its activity.
When the mutated gene was translated into a protein, the point mutation
led to the substitution of methionine for lysine as the 27th amino acid in this variant of histone H3 protein.
One such reassortment event (shift), rather than a point mutation
(drift), appears to explain the emergence of the A/Fujian/411/2002-like strain that caused an epidemic during the 2003 2004 influenza season.
DNA chips designed to detect point mutation
in solid tumors were developed by Lopez-Crapez et al.
A subgroup analysis of the patients with EGFR mutations demonstrated that the efficacy was slightly better among those with an Exon 19 deletion than those with an Exon 21 point mutation
. HR s of PFS were 0.38 for Exon 19 deletions and 0.55 for Exon 21 point mutations
A point mutation
at R345T which appears to result in loss-of-function when re-expressed in the mouse was found in 5925 healthy individuals with a heterozygous frequency of approximately 0.86% (about 4.500.000 European citizens).
Despite the fact that the methods cited above were highly sensitive when used for longitudinal screening of resistant patients known to have a specific point mutation
, some drawbacks exist.
Characteristics of preconceptional carcinogenesis in animal models, including non-Mendelian inheritance patterns (9), rates that are much higher than expected for point mutation
(10), and absence of mutations in cancer genes (11,12), have led us to propose that the mechanism is epigenetic (13,14).
In one, point mutation
, genes adapt through spontaneous mutations during DNA replication.
Using this protocol we screened 12 different nondeletional mutations, including 11 point mutations
, 1 five-nucleotide deletion, and 1 point mutation
associated with the -[[alpha].sup.3.7] rearranged [alpha]2/[alpha]1 gene (Table 1).
of bacterial artificial chromosomes by ET recombination.