Friday, March 24, 2017
Fancy genomics “Iam taking you all to the world of two-Speed genomes concept"
My Phd problem includes the various approaches for solving genome assembly problems. When I was working on oomycetes project, I was attracted by the effector proteins, Evolution, pathogenicity, synteny, transposon, Repeat regions, suddenly the fancy thing which came in the mind after reading an interesting paper from biorxiv that is verticullum genome, a group from Netherlands have sequenced and studied the 2-speed genome concepts among the strains. http://genome.cshlp.org/content/early/2016/07/12/gr.204974.116.full.pdf+html I was impressed by the work, then I showed the work to my PI even she was impressed by the speed genomes. I work in a collaborative program where exactly my collaborator also was fascinated by the speed genome work.
Let me explain what is 2 speed genomes?
It was already known that fungi and the plant pathogen genomes comprises of Effector proteins. Which plays an important role in causing pathogenicity to the host. These Effector genes are not randomly distributed across the genomes, tend to be associated with the compartments enriched with repeat sequences and transposons. This led to the ‘two-speed genome’ model in which filamentous pathogen genomes have a bipartite architecture with gene sparse, repeat rich compartments for adaptive evolution. The unusual genome architecture and occurrence of effector genes in specific genome compartments is a feature that has evolved repeatedly in independent phylogenetic lineages of filamentous pathogens. Genome analyses of and three of its sister species revealed uneven evolutionary rates across genomes with genes in repeat-rich regions showing higher rates of structural polymorphisms and positive selection. Two-speed genome architecture with the effector genes populating the more rapidly evolving sections of the genomes. Lineages that acquired two-speed genomes have increased survivability — they are less probabe to go extinct compared to lineages with less adaptable genomes, which are more probabe to be purged out of the biota as their hosts develop full resistance or become extinct. In this ‘jump or die’ model, pathogen lineages that have an increased likelihood to produce virulent genotypes on resistant hosts and non-hosts benefit from a macroevolutionary advantage and end up dominating the biota. Several filamentous plant pathogens have evolved by shifting or jumping from one host plant to another.
The information has been shared from this paper a great detailed review by Sophien and Raffaele et al its available here http://www.sciencedirect.com/science/article/pii/S0959437X15000945 .
For who don’t have access to science direct the same paper is available at biorxiv repository please find the link http://biorxiv.org/content/early/2015/07/01/021774