This reciprocal relationship between substitution frequency and the contribution of base order to fold potential is a characteristic of DNA sequences under positive selection. Indeed, the low (more positive) value of fold potential in an exon provides evaluation of the extent to which it has been under positive selection, without the need to compare two sequences (the classic way of determining if selection is positive or negative).
From Lewins Genes XII.
fold potential for them is the propensity of single stranded DNA to fold on itself once melted by polymerases.
Does this text just mean that the more an exon shows secondary structure, the more it is likely to have been selected for ?
I’m not entirely sure what “base clustering” means… does it refer to normal (or abnormal like G-G) base pairing, or to the cluster rule, the rule that the purines, A and G, tended to be clustered in one DNA strand of the DNA duplex?
This topic was modified 1 month, 2 weeks ago by Mehdi Saada.