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 P. infestans 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
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