Our interest in Painlevé VI arises from our exploration of
representations of finitely generated groups
encountered in models of topological quantum computing (TQC) [
1,
17] and the investigation of DNA/RNA short sequences crucial in transcriptomics [
2,
31]. A model of TQC can commence with a link such as the Hopf link
, whose character variety is the Cayley cubic surface
given in (
4). This surface is associated with the Picard solution of
, as mentioned at the end of the introduction. Other links, such as
or
[
1], whose character varieties contain the Fricke-Painlevé surfaces
for
and 3 can be utilized. To these surfaces one can attach solution 30 of Painlevé VI (see sub
Section 3.5 for the former case), and solutions 20 or 45 (see sub
Section 3.3 for the latter case).
It has been observed that the truncated Groebner basis of four-letter
groups encountered in the context of DNA/RNA sequences contains algebraic surfaces
for
and 4 as mentioned above, as well as the surface
[
2]. This surface corresponds to Fricke-Painlevé solution 31, with parameters
, associated with the symmetry of the great dodecahedron (see sub
Section 3.4). The surface with parameters
is also part of the Groebner basis for four-letter
groups. This reveals that many algebraic solutions of
, the Picard solution for the Cayley cubic
, solutions 20 and 45 associated to
, solutions 3, 21 and 42 for parameters
and the great dodecahedron solution 31 should play a role in genetics at the genome scale.
A Specific Example: (-Methyladenosine) Modifications
In the context of so-called epitranscriptomics there are chemical modifications that control the metabolism of transcription of the genetic information. More than 170 types of RNA methylation processes have been discovered. The most common for eukaryote organisms is the methylation of
-methyladenosine (
) on some sites
with a specific short sequence
(
or
G,
,
U or
C), see e.g. [
36,
37,
38]. In paper [
32], we provide a group theoretical analysis of such sequences. For instance, the Groebner basis of three-nucleotide sequences
and
contain algebraic surfaces of type
,
or
with
,
for the former sequence and
,
for the latter sequence. The exponent (*) in the surface
refers to the type of A-D-E (simple) singularity of the surface [
32]. In our view, the occurrence of such a simple singularity in the character variety of a relevant sequence is associated to a potential disease. In addition, we observe that the aforementioned singularities do not belong to the list of singularities found in the context of Painlevé VI.
Let us now pass to the four-nucleotide sequence
. This case is not investigated in much detail in [
32]. Below, we look at the the degree-2 Groebner basis associated to the character variety of group
. The degree
d-Groebner basis is the truncated Groebner basis obtained by ignoring polynomials of total degree larger than
d. In our case, we obtain algebraic surfaces of the Fricke-Painlevé type.
For a four-nucleotide sequence, the degree-2 Groebner basis contains 14-dimensional surfaces of the form in (instead of 7-dimensional surfaces of the form in the case of a three-nucleotide sequence).
For the sequence , we find that, for parameters , contain decoupled surfaces , , and corresponding to the Picard solution of Painlevé VI. For parameters , contains decoupled surfaces , as well as the Fricke-Painlevé surfaces with parameters and variables and . For parameters , contains the decoupled Fricke-Painlevé surfaces with parameters and variables , , and . Then, for parameters , contains the decoupled Fricke-Painlevé surfaces with parameters and variables , the Fricke-Painlevé surface , as well as the Fricke-Painlevé surfaces with parameters and variables , and .
These explicit calculations confirm our hypothesis that some algebraic solutions of Painlevé VI may govern the dynamical transcription in genomics.