| Mobile elements are important part of Junk DNA in the genomes. Study on them enables us to recognize that the impulsive effect of these repeat sequences on life diversity and their regulations of gene expression. This thesis has studied some distribution characteristics of k-word frequency in two kinds of protein sequences encoded by L1, and the splicing sites residing on Alu.The first part of the paper describes the periodicity of distribution of k-word frequencies in two kinds of protein sequences encoded by L1, and reveals that pairs of amino acids in the two kinds of sequences obey the Weibull distribution under the background of periodicity. Considering the difference between word domain and frequency domain, five types of functionals of k-word frequency, using Shannon information and Fisher information, are defined. We find that most relationships between functional and word length k follows exponential or logarithmic distribution.In the second part, analysis on the types and distribution of splicing sites in Alus is done, and indicates that non-canonical sites are abundant as a departure from the GT-AG rule. The frequencies of non-canonical splicing sites vary with chromosomes, such as more residing on chr. 11, chr. 12, chr. 17. By a statistical approach, we find that the splicing sites are subject to dinucleotide appearances in Alus, and thereby such repetitive elements have increased the versatility of the genome.
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