The

*Caenorhabditis elegans* (

*C*.

*elegans*) is a 1

mm length transparent nematode. Thanks to its simple organic structure, it was taken as a model for research into genetic field. Early studies on

*C*.

*elegans* began in 1962 with some works on cell lineage and apoptosis [

1,

2]. There are 2 distinct sexual types of the

*C*.

*elegans*, the hermaphrodite and the male. The second one is very rarely represented in nature (being approximately only the 0.05% of the population). We have 959 cells in the hermaphroditic species and 1031 cells for the male. The sexual difference at the chromosomal level provides: XX chromosomes for hermafrodite and X0 for the male. The sexual reproduction of

*C*.

*elegans* is realized by 2 distinct pathways: mating or, in case of the hermaphrodite, by a self-fertilization. The life cycle of

*C*.

*elegans* consists of 4 larval stages (from L1 to L4); however, if there exists some hard environment conditions, such as lacking of food, the

*C*.

*elegans* remains in the L3 larval stage, until the conditions improve.

The complete sequencing of

*C*.

*elegans* genome was completed in 2002. The

*C*.

*elegans* has 5 chromosomes autosomes plus the sex chromosome X. Totally, it is made up of nearly 100 million base pairs and 19000 genes [

3–

5]. Study on fractal analysis of multigenome of

*C*.

*elegans* has shown that chromosome 3 is the one with multifractal characteristics higher than the others, the less multifractal appears to be the chromosome sexual X [

6]. For the first time, in this work, we have analyzed the different types of sequences belonging to the genome of

*C*.

*elegans*, focusing our investigation on those that show fractal characteristics. Thus, chromosome 3 of

*C*.

*elegans* has been carefully studied because its unsymmetrical and inhomogeneous statistical characteristics. Through the analysis of this chromosome we can investigate what are the features that make it more “complex” from a biostatistical point of view and in particular with the use of statistical parameters such as the complexity, the fractal dimension, the matrix correlation, and the nucleotide frequency. The concept of fractality in biology is further clarified.

On the chromosome 3 of *C*. *elegans,* 2780 genes have been identified. In this paper, almost all nucleotide sequences that are located on chromosome 3 of *C*. *elegans* were analyzed and compared with random sequences. In particular, it will be shown that the nucleotide sequences with a low fractal value have common features with random sequence with low fractal dimension. Moreover, the highest fractal dimension corresponds to sequence close to random sequence with high fractal value, and in particular, it is shown a high frequency of cytosine.

From mathematical point of view, a fractal is a geometric object, characterized by the self-similarity; that is, it repeats its structure cyclically in the same way at different scales. A more rigorous definition of a fractal is based on four properties: self-similarity, fine structure, irregularities, and noninteger dimension [

7]. The fractal dimension is a parameter to compute the degree of complexity or disorder by measuring the unsmoothness of the object. This value enables to measure the amount of information contained in the sequence, the higher value corresponds to a higher information content. Generally, this value ranges between 1 and 2, so that the higher value corresponds to the higher complexity. Fractality has been observed and measured in pathology and cancer models [

8,

9], the study of branching blood vessels, or the irregularity of the contours of tumor cells [

10,

11], the analysis of complete genomes [

12], the correlation analysis of protein sequences [

13] tissue pathology [

14], in exons, introns [

15], and nuclei [

16], and it is involved in blood cancer [

17,

18].