28.02.2020 - 17:14
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Selenium and Genome Annotation (Sergi Castellano)

(Former group hosted by the Department of Evolutionary Genetics)

The group was a member of the Genetics Department from 2010 to 2017 and is moving to University College London.

Much of our work focuses on the identification and characterization of functional elements in eukaryotic genomes, primarily using selenium-dependent genes as our study system. On the one hand, we develop and apply methods to identify and annotate selenoprotein genes, which are usually missannotated in standard databases. On the other, we use population genetics and molecular evolution approaches to study the evolution of the use of selenocysteine, the selenium-containing amino acid, compared to cysteine in proteins. Because nutrition is a prominent selective force in humans and other primates, we are currently working in whether differences in dietary selenium have shaped the use and regulation of selenium and selenoproteins in these species. We are also interested in more theoretical aspects of sequence evolution.

Ongoing projects include:

  • Frédéric Romagné is working on the identification and correct annotation of selenoprotein genes. We have recently released annotations for more than 50 animal genomes for an update of our database of selenoproteins. Elias Mueller is working with Frédéric on this project.
  • Louise White is working on the identification of signatures of local adaptation to levels of dietary selenium in recent human evolution. Selenium in the diet varies widely among human populations and we have addressed this question through the resequencing of selenoprotein genes across populations around the world.
  • Gaurab Sarangi is working on the assessment of the exchangeability between cysteine and selenocysteine, the 21st amino acid in the genetic code, in protein function. In particular, we are interested in the role of compensatory mutations after the loss of selenocysteine in selenoproteins.

Since moving to MPI in 2010, we have also taken an interest in the analysis of ancient genomes. We are particularly interested in contributing to the population genetics analysis of Neandertals. In collaboration with the group of Svante Pääbo, we have recently analyzed the patterns of coding variation in Neandertals. We are also interested in the population history of Neandertals and have recently shown that, in addition to the known interbreeding events 50,000-60,000 years ago, Neandertals interbred with modern humans as early as 100,000 years ago. Despite these multiple interbreeding events, the Neandertal Y lineage is most likely extinct in modern humans.

Finally, we are collaborating with Aida Andrés in a number of projects on primate evolution.