Evolution In Networks Essay

1995 words - 8 pages

INTRODUCTION
Bio-molecular networks became popular during the last decade with the sudden increase in data about protein and other biomolecule interactions. Network representations of these data has allowed graph theory to be applied to bio-molecules and model the pairwise relationships between them where proteins and enzymes are characterized as network nodes and the interactions between them as network links (edges). The two types of networks typically constructed are protein-protein interaction maps and metabolic networks.
Metabolism is a fundamental process in all organisms that is carefully controlled to ensure their survival, but enzymes and proteins in metabolic pathways undergo ...view middle of the document...

Betweenness is the frequency with which a node is located on the shortest path between all other nodes. Metabolic flux is the rate at which reactants are converted into products by chemical reactions.
Evolution of a network i.e., addition and deletion of nodes and/or edges occur due to genetic changes. Gene duplication entails the addition of a network node and its associated edges whereas gene loss indicates that the node and its associated edges are lost. Mutations that disturb gene regulation, point mutations, deletions, insertions, inversions, shuffling, alternative splicing and domain accretion can also cause gain and loss of nodes and edges. On the other hand, network function may limit the kinds of mutations that can be accepted, and thus how genes evolve. It should be noted that the evolution of links is a lot more fine-tuned than that of nodes as links can change over time irrespective of whether or not nodes change.
DATASET AND METHODS
Greenberg et al studied adaptation and evolutionary constraint in twelve strains of Drosophila that are closely related to (and include) Drosophila melanogaster. The maximum likelihood estimates of rates of non-synonymous amino acid substitutions dN, synonymous substitutions dS and their ratio, ω (ω = dN/dS) were used for each gene. Then positive selection tests were performed using PAML (Model M8 against M7). Fuzzy reciprocal BLAST of every D.melanogaster gene against all other genomes was used to estimate rates of gene duplication. The metabolic network and pathway assignment of D.melanogaster was obtained from KEGG and gene information & mutation phenotypes from FlyBase. Evolutionary rates were calculated for 447 genes. Partial correlations were used to assess the weight of each network parameter. Permutation tests were used to evaluate P values and for enzymes that belonged to multiple pathway groups and enzymes encoded by multiple genes, modified permutation tests were used.
Vitkup et al investigated how the topology of a metabolic network and its reaction fluxes affect the evolution of network genes through point mutations and gene duplications in the yeast Saccharomyces cerevisiae and three other yeast species. To elicit only genuine functional relationships, 14 most connected metabolites and co-factors were excluded from most calculations. This resulted in about 5% of network enzymes becoming disconnected from the network. Unlike the earlier study, this study used Ks, Ka and Ka/Ks values in their calculations. The calculations were based on the maximum likelihood models of Muse & Gaut and Goldman & Yang for estimating gene duplication rates, previously published studies and the maximum likelihood model of Yang & Nielsen for Ks, Ka and Ka/Ks. They also performed partial correlation analysis to relate network parameters.
Montanucci et al analyzed the evolutionary constraints of the N-glycan pathway by estimating the dynamics, dispensability of the pathway components, biological & topological...

Find Another Essay On evolution in networks

Network theory of internalization and social capital in internalization

964 words - 4 pages of value chain has evolved in recent years rising to become the concept of value networks where the links of the value chain are invested in flow management and is part of customer preferences followed by management all business processes, distribution, product design, etc. . To deliver a deal valued by the market. In this new approach, enterprise networks where nodes are actors, companies, individuals or entities from which the interdependent

Marketing Through Social Media Essay

3843 words - 15 pages which are about the social evolution and about the interaction. In Web 1.0, the Internet user was passive, he could only consult, look or listen. Now, the user is at the heart of the Web, he is capable of acting on the contents, of developing it and sharing it. It is partially what explains the number of people who go on these social networks today. The social networks are not something new in the life of the individuals, but today it is

Evolution Unwound

821 words - 4 pages The videos show and discuss many issues about the theories of evolution. In order to fully understand the concepts depicted, all the videos must be viewed. By following this string of videos we discover that since the beginning of time the evolution life has been a constantly unwinding mystery; how unproven theories and outrageous speculations hindered scientists in their quests to unwind these mysteries; how many theorists were afraid to

Neural Network Concept in Artificial Intelligence

1918 words - 8 pages otherwise. Hopfield networks store information via their local stable points in the state space, which are referred as attractors. The information retrieval is performed by state evolution. The information is retrieved when the state evolution reaches a local stable point. Hopfield structure is very effective in the implementation of associative memories. Associative memory works much more like our mind does. If we are for instance looking for

Charles Darwin's Life and Accomplishments

993 words - 4 pages Charles Darwin was born in February 12,1809. When Charles Darwin was a little kid he struggled a lot in school. In 1825 Charles become a fortunate person and went to medical school. Darwin was a British scientist who set the foundations of the theory of evolution and converted the way we imagine about the natural world. Charles Darwin was the discoverer of the biological theory of evolution. Charles Darwin was married for 43 years to Emma Darwin

Ancient Penguin Discoveries and Evolution

1325 words - 5 pages Ancient Penguin Discoveries and Evolution In a recent BBC News article, Ivan Noble discusses the possibility that ancient penguins may hold the key to unlocking the mysteries behind the complicated molecular clock of evolution. Although a seemingly unlikely animal to research, prehistoric penguin remains in the Antarctic often have been the basis for study, research, as well as debate in the modern science world. Because the

Business Environment and Networks

1046 words - 5 pages relationship in a changing scenario of strong competition and emerging value creation networks? The objective is to explore the importance and influence of communication in contemporary inter firm relationships in the value creation networks. In the first session of the essay a literature review on the evolution of the concept of value chain to value network will be discussed. The second session of the essay will analyse the importance of inter firm

Database, Data Warehouse and Mobile Internet

894 words - 4 pages increased the power of their mobile networks allowing higher-speed transmissions. The next evolution in wireless communication, called 4G networks, is entirely packet switched and capable of 100 Mbps transmission speed, with premium quality and high security (Laudon & Laudon, 2012). Overall, convenience is the greatest advantage mobile wireless networks have over wired networks. Wireless networks are slower, less reliable, and less secure than wired

Artificial Neural Networks

1124 words - 4 pages the ANN and changes the weights accordingly to reduce the error rate. All ANNs before training start with random values for each of the weights and through training these weights are fine-tuned using the back propagation algorithm to produce the best output. Neural networks carry great promise in technological evolution but are faced with some obstacles of their own. For one, they need to be extensively trained which could take massive amounts

Social Network and its Impact in America

2019 words - 9 pages . Over time, American culture has been transformed by the evolution of social networking in both good and bad forms. As individuals become more and more involved with these sites, social networks become a key asset of people’s lives. For communication, social networks have allowed friends and families to stay instantly updated about one another when they are separated. In recent days, the use of social networks has become more present in our

What is a 4G Network?

727 words - 3 pages conferencing, 3D TV and cloud computing. Two candidate 4G system used custom commercial Mobile WiMAX (first used in Asian countries in 2006) and therefore the first release – the future of Evolution (LTE) custom ( in the capital and the country’s capital Norge, Sverige since 2009). But have debate if the first – release version should be thought – about to be 4G or not, has stated in the technical definition section below. The top contenders are LTE and

Similar Essays

An Advanced Grammatical Evolution Approach For Intrusion Detection In Manet

1347 words - 6 pages for mobile ad hoc networks. Int. Journal ofAd Hoc and Sensor Wireless Networks, 2(3), 2003. [9] A. Smith. An examination of an intrusion detection architecture for wireless ad hoc networks. In Proceedings of the 5th National Colloquium for Information System Security Education, 2001. [10] Bonnmotion: A mobility scenario generation and analysis tool. [11] libge: A c++ library for grammatical evolution. [12] Ns-2: The network simulator. [13] A

Wireless Sensors Networks Security Essay

2213 words - 9 pages issues. The remainder of this paper is organised in the following way. Section 2 provides a brief overview of wireless sensor networks, their evolution, major research initiatives and future applications. In section 3, security issues and challenges are discussed. Section 4 highlights the related work in sensor networks. Section 5 concludes the paper by posing some questions and future directions. 2. An Overview Sensor networks are

Networks And Modern Communications Essay

3036 words - 12 pages the appearance of a "flexibly separable" network management layer, embodied in the software that controls modern networks. Network control no longer required network ownership and could be shared among various participants in the telecom infrastructure: network owners and operators, network users, and third parties. This enabled a new evolution of network practices, building upon network experimentation and re-configuration, which we characterized

Letter Of Recommendation Essay

824 words - 4 pages of an array of corroborating tools and technologies. The evolution of Social Networks is still in its infancy, for we have just seen a glimpse of its true potential in the last few years. Social Networks have an enormous impact on the society, ameliorating our lives by creating a unified place to share thoughts with people. It has in fact created a virtual world where people exchange their thoughts and stay connected. However, there is a negative side to it as well, like the security of Information and problems of asocial behavior due to its excessive use. They might entice people to waste time and can sometimes be responsible for exacerbating a student’s grade.