Lucia Pettinato - INFN Firenze #
Statistical analysis of promoter sequences #
<p>
Promoters are DNA sequences located upstream of each gene. Through 
various biochemical mechanisms, they regulate the transcription rate of 
the corresponding gene, directing when and in which tissues the 
information stored in the gene must (or must not) be used.
</p><p>
In this work, I analyze a sample of promoters of Homo sapiens, to search 
for statistically significant properties of promoter sequences. A 
clustering algorithm, specifically developed, identifies classes of 
promoters with similar statistical base composition properties. The 
classes obtained are further characterized developing an algorithm to 
detect regular regions (i.e. periodic or homogeneous in composition): 
such regions are known to have an important role in determining the 
promoter functions.
</p><p>
The combination of these methods allows to identify and characterize 
three classes of promoters in Homo sapiens; it also gives crucial clues 
to grasp the pervasive presence of transposons (DNA sequences capable to 
move from one location on the genome to another) in one of these 
classes. This analysis, repeated for other species, allows a comparison 
to search for evolutionary trends in promoter structure.
</p>