tRNA genes

All natural yeast chromosomes contain one or more yeast tRNA genes, or tDNAs. We are testing the effect of removing all tDNAs from the synthetic chromosomes and re-locating them to a separate “neochromosome”. The strategy here is to encode all tDNAs from a particular chromosome on a centromeric plasmid so that once synthetic chromosome incorporation in yeast is complete the balance of tDNAs will be identical to the starting strain. Re-location of tDNAs is important because they are hotspots for transposition and genome rearrangements. As such, the synthetic chromosomes may well be quite resistant to such recombinational events relative to normal chromosomes, and generally produce a more stable genome. We refer to the tDNA “neochromosome” as the “party chromosome” because we expect the tRNA genes to be unstable, however this instability will be isolated from the synthetic chromosomes.  This neochromosome or chromosome “tDNA block” will grow as the synthesis project proceeds.