N. A. Zaytseva1, F. A. Kondrashov2, P. K. Vlasov2

1Siberian Federal University, Krasnoyarsk, Russia2Centre for Genomic Regulation, Barcelona, Spain

1

The global tRNA evolution within the total sequence space has not been explored.

The lack of data on the distribution and evolution of the sequences makes a significant gap in our understanding of evolution of amino acids and genetic code.

2

• GoalDemonstration of transition possibility one group tRNA to another

• Tasks1) To obtain a picture of groups tRNA distribution

2) To assess the divergence of sequences within each group of tRNA 

3

The analysis is based on the model of the ongoing expansion of the protein universe.

4

The rate of divergence of distant homologues is analogous to speed in Hubble’s analysis; the distance between sequences is analogous to physical distance.

5

5787 sequences of mitochondrial tRNAs (Tetrapoda) were analyzed

The sequences were retrieved from http://www.umich.edu/~kondrash/Database/

The general database (Tetrapoda) was divided into four databases: Mammalia, Aves, Amphibia and Reptilia

6

Step 1. The consensus sequences for each group of tRNA were determined.

Step 2. The values of effective radius were computed.

Step 3. The distances from all the sequences to each consensus were calculated.

Step 4. The sequences, which are located in the effective radius of another groups, were identified.

7

• Picture 1— Reduced version of intersection matrix (Tetrapoda).

Consensus/ Group of tRNA

His Ile LeuU Tyr Gly Arg

His 51%

Ile 77%

LeuU 68%

Tyr 18% 48% 19%

Gly 3%

Arg 7%

Table 1 — Values of effective radius for some tRNA groups.

9

Group of tRNA Effective radius

Tyr 0,3333

His 0,2916

Ile 0,3125

Leu 0,2916

Average value (for 21 group)

0,3026

Table 2— Average value of effective radius for each database.

Table 3— Number of tRNA sequences in each database.

10

Tetrapoda

Reptilia Amphibia

Mammalia

Aves

5760 650 1106 3076 945

Tetrapoda

Reptilia Amphibia

Mammalia

Aves

0,3026 0,2954 0,2668 0,2004 0,1240

Picture 2— Correlation between effective radius and origin time of group.

11

Picture 3— Correlation between value of effective radius and chronology of amino acids origin.

12

Histidine, isoleucine, lecine and tyrosine form cluster. In the center of cluster the tyrosine group is located.

There is a correlation between the effective radius and origin time of group of species taken into consideration.

The value of the effective radius is independent on the chronology of amino acids origin.

13

When the investigation is finished, we will have a better understanding of the nature of tRNA distribution in sequence space.

14

Fyodor KondrashovPeter VlasovMichael Sadovsky

This work was supported by grant from Russian government department of Science and Education to Siberian Federal University «The genetic researcher of the Siberian larch»

15