The validation results for sub-sets of EST-SSR markers demonstrated that inclusion of non-domesticated genotypes in the study increased rates of polymorphism detection, consistent with the results of similar studies [ 8, 55].
This increased rate of polymorphism can possibly be attributed to the genomic instability and loss of DNA repair mechanisms that would have contributed to the original malignancy [ 31] as well as the number of passages the cell-line would have undergone since the original isolation in 1977, and during which additional mutations would have accrued [ 11].
If natural selection is not strong enough to counteract this elevated mutation rate, increased rates of indel polymorphism and divergence are expected under this mutation bias model as well.
In a more recent study, no association of this polymorphism with either thermal pain generated by a thermode (32° 52°C at increasing rate of 1°C/s) was observed in Caucasian volunteers experiencing experimental pain [ 30].
Interestingly, every twofold degenerate amino acid has an increased rate of synonymous polymorphism compared with the three-, four-, and sixfold degenerate amino acids.
While the power of this study is compromised by the small sample size, the analysis did demonstrate a link between specific cytochrome p450 polymorphisms and an increased rate of TGCT development.
It is also known that endothelial dysfunction associates with an increased rate of cerebrovascular ischemic events, and genetic factors (such as angiotensin-converting enzyme insertion/deletion, methylenetetrahydrofolate reductase C677T polymorphisms, and von Willebrand factor activity) which increase the susceptibility of endothelial dysfunction have been linked to migraine [21, 22].
McGrath et al. reported on the correlation of a polymorphism that increases the degradation efficiency of CYP1B1 with decreased cancer risk, suggesting that an increased rate of CYP1B1 protein degradation mediates a protective effect against tumorigenesis (22, 23).
If the polymorphism results in reduced repair efficiency, the resultant increased levels of DNA damage may lead to an increased rate of apoptosis.
Polymorphisms in DNA repair genes are thought to be a risk factor for cancer as a result of increased rate of mutations.
