**2. The relevant regions in chromosomes**

The specific succession in the bases (A, G, C, and T) constitutes the hereditary message. Each DNA fragment involves a specific protein synthesis process. Proteins are synthesized from a set composed of 20 different amino acids, which are determined by three bases occurring in subsequent order. A group of three consecutive nucleotides with desoxyribose and phosphoric group is called a codon and a total of 64 different combinations specify 20 amino acids and three stop codons, namely TAA, TAG, and TGA. The protein synthesis (Fig.1) is realized in two steps: (1) the transcription within which the hereditary information is copied into the messenger RNA and, (2) the translation in which the messenger RNA is exploited by the ribosome to form the amino acid chain. To obtain numerical data from this succession of symbolic bases of a DNA sequence, we use binary indicator coding techniques.

Fig. 1. The protein's synthesis steps

In a DNA sequence, electron microscopy and biochemical studies have established that the bulk of the chromatin DNA is compacting into repeating structural units, named nucleosomes. A model of this DNA structure in such regions is proposed by Kornberg in (Kornberg, 1974, 1977). The chromatin is a dynamic structure, oscillating between the nucleosome and open structures depending on the environmental conditions (Kornberg, 1974, 1977; Oudet et al, 1978). And each nucleosome is formed by two molecules of each histone (protein) H2A, 206 Fourier Transform Applications

methodology that generates results to highlight the periodicities studied. This analysis is based on organisms translated into signals by three coding techniques. The algorithm steps of this technique are detailed to mention the generation method of spectrums and spectrograms. The fourth part deals with the study of the frequencies' evolution. It present results for smoothed STFT, as a 1D, 2D or 3D spectrogram representation. Part five

The specific succession in the bases (A, G, C, and T) constitutes the hereditary message. Each DNA fragment involves a specific protein synthesis process. Proteins are synthesized from a set composed of 20 different amino acids, which are determined by three bases occurring in subsequent order. A group of three consecutive nucleotides with desoxyribose and phosphoric group is called a codon and a total of 64 different combinations specify 20 amino acids and three stop codons, namely TAA, TAG, and TGA. The protein synthesis (Fig.1) is realized in two steps: (1) the transcription within which the hereditary information is copied into the messenger RNA and, (2) the translation in which the messenger RNA is exploited by the ribosome to form the amino acid chain. To obtain numerical data from this succession

**exon intron**

In a DNA sequence, electron microscopy and biochemical studies have established that the bulk of the chromatin DNA is compacting into repeating structural units, named nucleosomes. A model of this DNA structure in such regions is proposed by Kornberg in (Kornberg, 1974, 1977). The chromatin is a dynamic structure, oscillating between the nucleosome and open structures depending on the environmental conditions (Kornberg, 1974, 1977; Oudet et al, 1978). And each nucleosome is formed by two molecules of each histone (protein) H2A,

**Peptides**

**genes**

**Splicing mRNA Traduction**

of symbolic bases of a DNA sequence, we use binary indicator coding techniques.

**DNA sequence**

**Transcription**

Fig. 1. The protein's synthesis steps

concludes this chapter.

**2. The relevant regions in chromosomes** 

H2B, H3 and H4. Each nucleosome has a diameter of 12.5±1 nm and contains about 200 base pairs of DNA. This number is varying according to the chromatin's origin (Hayes et al 1990; Kornberg, 1977; Oudet et al, 1978; Worcel et al 1981). In contrast a particle named 'nucleosome core' is invariant in its DNA content about 146 base pairs. Interesting electron microscopic evidence elaborated in (Oudet et al, 1978) suggests that under appropriate conditions a nucleosome could open up into two separate half nucleosomes of diameter 9.3±1 nm. The finding of each type of histones in the nucleosome has suggested that a nucleosome could be made up of two symmetrical halves (Altenburger, 1976).

Fig. 2. Chromatine's and nucleosome's structure

In order to study the protein coding regions signals and the nucleosome regions ones, the DNA symbolic data must be converted to DNA signals.
