A Quantitative Model for Human Olfactory Receptors

A wide variety of chemicals having distinct odors are smelled by humans. Odor perception initiates in the nose, where it is detected by a large family of olfactory receptors (ORs). Based on divergence of evolutionary model, a sequence of human ORs database has been proposed by D. Lancet et al (2000, 2006). It is quite impossible to infer whether a given sequence of nucleotides is a human OR or not, without any biological experimental validation. In our perspective, a proper quantitative understanding of these ORs is required to justify or nullify whether a given sequence is a human OR or not. In this paper, all human OR sequences have been quantified, and a set of clusters have been made using the quantitative results based on two different metrics. Using this proposed quantitative model, one can easily make probable justification or deterministic nullification whether a given sequence of nucleotides is a probable human OR homologue or not, without seeking any biological experiment. Of course a further biological experiment is essential to validate the probable human OR homologue

Underlying Mathematics in Diversification of Human Olfactory Receptors in Different Loci

As per conservative estimate, approximately (51-105) Olfactory Receptors (ORs) loci are present in human genome occurring in clusters. These clusters are apparently unevenly spread as mosaics over 21 pair of human chromosomes. Olfactory Receptor (OR) gene families which are thought to have expanded for the need to provide recognition capability for huge number of pure and complex odorants. ORs form the largest known multi-gene family in the human genome. Recent studies have shown that 388 full length and 414 OR pseudo-genes are present in these OR genomic clusters. In this paper, the authors report a classification method for all human ORs based on their sequential quantitative information like presence of poly strings of nucleotides bases, long range correlation and so on. An L-System generated sequence has been taken as an input into a star-model of specific subfamily members and resultant sequence has been mapped to a specific OR based on the classification scheme using fractal parameters like Hurst exponent and fractal dimensions