dorsal/arxiv
View SchemaEvidence of a universal power law characterizing the evolution of metabolic networks
| Authors | Shalini, Areejit Samal, Varun Giri, Sandeep Krishna, N. Raghuram, Sanjay Jain |
|---|---|
| Categories | |
| ArXiv ID | q-bio/0504015 |
| URL | https://arxiv.org/abs/q-bio/0504015 |
Abstract
Metabolic networks are known to be scale free but the evolutionary origin of this structural property is not clearly understood. One way of studying the dynamical process is to compare the metabolic networks of species that have arisen at different points in evolution and hence are related to each other to varying extents. We have compared the reaction sets of each metabolite across and within 15 groups of species. For a given pair of species and a given metabolite, the number $\Delta k$ of reactions of the metabolite that appear in the metabolic network of only one species and not the other is a measure of the distance between the two networks. While $\Delta k$ is small within groups of related species and large across groups, we find its probability distribution to be $\sim (\Delta k)^{-\gamma'}$ where $\gamma'$ is a universal exponent that is the same within and across groups. This exponent equals, upto statistical uncertainties, the exponent $\gamma$ in the scale free degree distribution $\sim k^{-\gamma}$. We argue that this, as well as our finding that $\Delta k$ is approximately linearly correlated with the degree $k$ of the metabolite, is evidence of a `proportionate change' process in evolution. We also discuss some molecular mechanisms that might be responsible for such an evolutionary process.
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"abstract": "Metabolic networks are known to be scale free but the evolutionary origin of\nthis structural property is not clearly understood. One way of studying the\ndynamical process is to compare the metabolic networks of species that have\narisen at different points in evolution and hence are related to each other to\nvarying extents. We have compared the reaction sets of each metabolite across\nand within 15 groups of species. For a given pair of species and a given\nmetabolite, the number $\\Delta k$ of reactions of the metabolite that appear in\nthe metabolic network of only one species and not the other is a measure of the\ndistance between the two networks. While $\\Delta k$ is small within groups of\nrelated species and large across groups, we find its probability distribution\nto be $\\sim (\\Delta k)^{-\\gamma\u0027}$ where $\\gamma\u0027$ is a universal exponent that\nis the same within and across groups. This exponent equals, upto statistical\nuncertainties, the exponent $\\gamma$ in the scale free degree distribution\n$\\sim k^{-\\gamma}$. We argue that this, as well as our finding that $\\Delta k$\nis approximately linearly correlated with the degree $k$ of the metabolite, is\nevidence of a `proportionate change\u0027 process in evolution. We also discuss some\nmolecular mechanisms that might be responsible for such an evolutionary\nprocess.",
"arxiv_id": "q-bio/0504015",
"authors": [
"Shalini",
"Areejit Samal",
"Varun Giri",
"Sandeep Krishna",
"N. Raghuram",
"Sanjay Jain"
],
"categories": [
"q-bio.MN",
"cond-mat.dis-nn",
"q-bio.PE"
],
"title": "Evidence of a universal power law characterizing the evolution of metabolic networks",
"url": "https://arxiv.org/abs/q-bio/0504015"
},
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