LAUSR

Motivation: In the evolution of species, a kind of special sequences, termed ultraconserved sequences (UCSs), have been inherited without any change, which strongly suggests those sequences should be crucial for the species to survive or adapt to the environment. However, the UCSs are still regarded as mysterious genetic sequences so far. Here, we present a systematic study of ultraconserved genomic regions in the budding yeast based on the publicly available genome sequences, in order to reveal their relationship with the adaptability or fitness advantages of the budding yeast. Results: Our results indicate that, in addition to some fundamental biological functions, the UCSs play an important role in the adaptation of S. cerevisiae to the acidic environment, which is backed up by the previous observation. Besides that, we also find the highly unchanged genes (HUGs) are enriched in some other pathways, such as the nutrient-sensitive signaling pathway. To facilitate the investigation of unique UCSs, the UCSC Genome Browser was utilized to visualize the chromosomal position and related annotations of UCSs in S. cerevisiae genome. Contact: [email protected] Supplementary information: Supplementary data are available at Bioinformatics online.