Non-random distribution of breast cancer susceptibility loci on human chromosomes

Non-randomness distribution of micro-RNAs on human chromosomes

Background

Micro-RNA (miRNA) is one of the non-coding RNAs that exist in human genome. miRNAs play an important role in the expression of target genes. Several studies have indicated that organization of human genome is not random. In order to investigate the distribution of miRNAs on human chromosomes, the present study was carried out.

Results

Using the data from miRBase database, we found 1913 loci coding for miRNAs (MIRs). Human chromosome bands 1p36, 1q22, 1q24, 2q13, 2q35, 3p21, 6p21, 7q22, 8p23, 8q24, 9q22, 9q34, 11q12-q13, 12q13, 14q32, 16p13, 16q24, 17p13, 17q11, 17q21, 17q25, 19p13, 19q13, 20q13, 21p11, 22q13, and Xq26-q28 were significantly bearing higher number of MIRs. The 14q32 and 19q13 with 4.11 and 3.59 MIRs per mega-base pair, respectively, were the most MIR-richest human chromosomal bands. The number of MIRs on chromosomal bands significantly decreased as a function of distance from telomere (r = − 0.949, df = 5, P = 0.001).

Conclusions

Our current data suggest that MIRs are not randomly distributed on human genomes.

Chromosomal distribution of schizophrenia susceptibility loci

In order to find the chromosomal distribution of polymorphic loci associated with the schizophrenia risk, the present study was carried out. Meta-analysis studies with information of genetic polymorphisms and schizophrenia risk were identified and used for the present study. There were 39 loci associated with schizophrenia risk. Statistical analysis revealed that the schizophrenia susceptible loci distributed non-randomly on human chromosomes. Human chromosome segments 6p21.1-p22.3 (P < 0.001) bear significantly higher number of susceptible loci.