310 likes | 321 Vues
Biomathematics seminar. Application of Fourier to Bioinformatics. Girolamo Giudice. Background. −1 + 3 i and −1 − 3 i ,. Background. Z = −1 + 3 i. Complex plane. Periodic and aperiodic function. Periodic function. Aperiodic function. Sine (or cosine) wave.
E N D
Biomathematics seminar Application of Fourier to Bioinformatics Girolamo Giudice
Background −1 + 3i and −1 − 3i,
Background Z = −1 + 3i Complex plane
Periodic and aperiodic function Periodic function Aperiodic function
Sine (or cosine) wave • A the amplitude, is the peak deviation of the function from zero. • F the frequency, is the number of oscillations (cycles) that occur each second of time. • ω = 2πf, the angular frequency , how many cycles occur in a second • φ the phase , specifies (in radians) where in its cycle the oscillation is at t = 0.
Harmonic analysis and Fouries series It is possible to express periodic function into the sum of a (possibly infinite) set sinesand cosines (or, equivalently, complex exponentials). Quadrature Fourier Series Euler Formula Complex Fourier series
Spectrum Fourier Series Spectrum
Example A=5 0
Fourier transform Continuous Domain Discrete domain Complex Fourier series Inverse Fourier Transform
Binary Indicator Sequences Any three of the four indicator sequences completely characterize the full DNA character string. Indicator sequences can be analyzed to identify in the structure of a DNA string.
Period-3 property PS of a protein coding region PS of a non-coding region
Resonant Recognition Model • The energy of delocalized electrons in amino acids produce the strongest impact on the electronic distribution of the whole protein because produce electromagnetic irradiation or absorption with spectral characteristics corresponding to energy distribution along the protein
Repetita Permit to find periodicities hidden along the sequence.
MSA with Fourier - MAFFT Homologous regions are quickly identified by converting amino acid residues to vectors of volume and polarity is If are the volume component of the nth site
Recursive Splicing Intron Exon Intron Exon Exon Pre-mRNA motifs RNA Binding protein
Take home message Fourier transform and Fourier series have the same purpose: decompose a signal in sum of waves. It was possible: • Detect hidden signal (period-3 property) • Filtering noise (identify Protein-Coding Regions) • Detect periodicity (Repetita) • Detect common structure and sequence similarities (Resonant recognition model, MAFFT) • Denoising and reconstructing signals( Recursive splicing) • Reduce computational time ( MAFFT)