Selenoproteins are selenocysteine-containing proteins that have been identified throughout all 3 kingdoms of life. Comparison of various animal species shows that some organisms lost the selenocysteine insertion machinery during evolution. Moreover, some selenoproteins were lost, whilst others emerged during evolutionary history. Therefore, this evolutionary events make it possible to stablish genetical similarities and divergence processes that enable scientists to better understand the phylogenetic relationships between different species.

The aim of the current study is to define the selenoproteome (including the required machinery to synthetize selenoproteins) of the species Parus major by comparing it to the selenoproteome of Gallus gallus: a species used as a reference, as it has previously been characterized.

To do so, the genome of Parus major was obtained and indexed, and the in silico homology analysis was carried out by combining the following bioinformatic tools: automatization processes and running of tBlastx, Exonerate and T-Coffee. Finally, the SECISearch3/Seblastian was run in order to get the predicted selenoproteins and their corresponding SECIS elements.

With the implementation of this procedure X selenoproteins (comentar hom[olegs I altres resultats trobats en la maquinaria I en les selenos) have been identified in the genome of Parus major.