Science,
Journal Year:
2021,
Volume and Issue:
374(6569)
Published: Nov. 11, 2021
A
closer
look
at
centromeres
Centromeres
are
key
for
anchoring
chromosomes
to
the
mitotic
spindle,
but
they
have
been
difficult
sequence
because
can
contain
many
repeating
DNA
elements.
These
repeats,
however,
carry
regularly
spaced,
distinctive
markers
of
heterogeneity
between
mostly,
not
completely,
identical
repeats.
Such
differences
aid
assembly.
Naish
et
al
.
used
ultra-long-read
sequencing
establish
a
reference
assembly
that
resolves
all
five
in
small
mustard
plant
Arabidopsis
Their
view
into
subtly
homogenized
world
reveals
retrotransposons
interrupt
centromere
organization
and
repressive
methylation
excludes
from
meiotic
crossover
repair.
Thus,
evolve
under
opposing
forces
homogenization
retrotransposon
disruption.
—PJH
Genome Research,
Journal Year:
2018,
Volume and Issue:
28(4), P. 532 - 546
Published: March 12, 2018
Meiotic
recombination
initiates
from
DNA
double-strand
breaks
(DSBs)
generated
by
SPO11
topoisomerase-like
complexes.
DSB
frequency
varies
extensively
along
eukaryotic
chromosomes,
with
hotspots
controlled
chromatin
and
sequence.
To
map
meiotic
DSBs
throughout
a
plant
genome,
we
purified
sequenced
Arabidopsis
thaliana
SPO11-1-oligonucleotides.
SPO11-1-oligos
are
elevated
in
gene
promoters,
terminators,
introns,
which
is
driven
AT-sequence
richness
that
excludes
nucleosomes
allows
SPO11-1
access.
A
positive
relationship
was
observed
between
crossovers
genome-wide,
although
fine-scale
correlations
were
weaker.
This
may
reflect
the
influence
of
interhomolog
polymorphism
on
crossover
formation,
downstream
formation.
Although
H3K4me3
enriched
proximity
to
SPO11-1-oligo
at
5′
ends,
levels
do
not
correlate
DSBs.
Repetitive
transposons
thought
be
silenced
during
meiosis,
prevent
nonallelic
interactions
genome
instability.
Unexpectedly,
found
high
nucleosome-depleted
Helitron/Pogo/Tc1/Mariner
transposons,
whereas
retrotransposons
coldspots.
High
within
regulatory
regions
immunity
genes,
suggesting
role
as
enhancers.
As
transposon
mobility
genomes
restricted
methylation,
used
met1
methyltransferase
mutant
investigate
heterochromatin
distributions.
Epigenetic
activation
centromeres
occurred
mutants,
coincident
reduced
nucleosome
occupancy,
gain
transcription,
H3K4me3.
Together,
our
work
reveals
complex
A.
genes
significance
for
diversity
evolution
genomes.
Nature Communications,
Journal Year:
2022,
Volume and Issue:
13(1)
Published: March 14, 2022
Abstract
A
contribution
of
DNA
methylation
to
defense
against
invading
nucleic
acids
and
maintenance
genome
integrity
is
uncontested;
however,
our
understanding
the
extent
involvement
this
epigenetic
mark
in
genome-wide
gene
regulation
plant
developmental
control
incomplete.
Here,
we
knock
out
all
five
known
methyltransferases
Arabidopsis
,
generating
methylation-free
plants.
This
quintuple
mutant
exhibits
a
suite
defects,
unequivocally
demonstrating
that
essential
for
multiple
aspects
development.
We
show
CG
non-CG
are
required
plethora
biological
processes,
including
pavement
cell
shape,
endoreduplication,
death,
flowering,
trichome
morphology,
vasculature
meristem
development,
root
fate
determination.
Moreover,
find
has
strong
dose-dependent
effect
on
expression
repression
transposable
elements.
Taken
together,
results
demonstrate
dispensable
survival
but
proper
processes.
Genome biology,
Journal Year:
2024,
Volume and Issue:
25(1)
Published: Jan. 22, 2024
Centromeres
load
kinetochore
complexes
onto
chromosomes,
which
mediate
spindle
attachment
and
allow
segregation
during
cell
division.
Although
centromeres
perform
a
conserved
cellular
function,
their
underlying
DNA
sequences
are
highly
divergent
within
between
species.
Despite
variability
in
sequence,
also
universally
suppressed
for
meiotic
crossover
recombination,
across
eukaryotes.
However,
the
genetic
epigenetic
factors
responsible
suppression
of
centromeric
crossovers
remain
to
be
completely
defined.
Genetics,
Journal Year:
2019,
Volume and Issue:
213(3), P. 771 - 787
Published: Sept. 16, 2019
Abstract
Rowan
et
al.
generated
a
dataset
of
over
17,000
meiotic
crossovers
(COs)
from
2000
F2
individuals
single
Arabidopsis
thaliana
cross.
The
unprecedented
density
COs
and
the
high-quality
reference
genomes
two...
Many
environmental,
genetic,
epigenetic
factors
are
known
to
affect
frequency
positioning
(COs).
Suppression
by
large,
cytologically
visible
inversions
translocations
has
long
been
recognized,
but
relatively
little
is
about
how
smaller
structural
variants
(SVs)
COs.
To
examine
fine-scale
determinants
CO
landscape,
including
SVs,
we
used
rapid,
cost-effective
method
for
high-throughput
sequencing
generate
precise
map
>17,000
between
Col-0
Ler-0
accessions
thaliana.
were
generally
suppressed
in
regions
with
this
effect
did
not
depend
on
size
variant
region,
was
only
marginally
affected
type.
suppression
extend
far
beyond
SV
borders
rates
slightly
elevated
flanking
regions.
Disease
resistance
gene
clusters,
which
often
exist
as
exhibited
high
at
some
loci,
there
tendency
toward
depressed
loci
where
large
differences
two
parents.
Our
high-density
also
revealed
fine
detail
relates
genetic
(DNA
motifs)
(chromatin
structure)
features
genome.
We
conclude
that
occurs
narrow
region
spanning
large-
small-scale
representing
an
influence
landscape
addition
sequence
variation
along
chromosomes.
PLoS Genetics,
Journal Year:
2020,
Volume and Issue:
16(7), P. e1008872 - e1008872
Published: July 16, 2020
Transposable
elements
(TEs)
are
genomic
parasites
that
selfishly
replicate
at
the
expense
of
host
fitness.
Fifty
years
evolutionary
studies
TEs
have
concentrated
on
deleterious
genetic
effects
TEs,
such
as
their
disrupting
genes
and
regulatory
sequences.
However,
a
flurry
recent
work
suggests
there
is
another
important
source
TEs’
harmful
effects—epigenetic
silencing.
Host
genomes
typically
silence
by
deposition
repressive
epigenetic
marks.
While
this
silencing
reduces
selfish
replication
should
benefit
hosts,
picture
emerging
triggers
inadvertent
spreading
marks
to
otherwise
expressed
neighboring
genes,
ultimately
jeopardizing
In
Review,
we
provide
long-overdue
overview
genome-wide
evidence
for
presence
prevalence
effects,
highlighting
both
similarities
differences
across
mammals,
insects,
plants.
We
lay
out
current
understanding
functional
fitness
consequences
propose
possible
influences
evolution
hosts
themselves.
These
unique
indicate
effect
not
only
crucial
component
TE
biology
but
could
also
be
significant
contributor
genome
function
evolution.
Frontiers in Plant Science,
Journal Year:
2018,
Volume and Issue:
9
Published: June 28, 2018
Polyploidization
is
a
widespread
phenomenon,
especially
in
flowering
plants
that
have
all
undergone
at
least
one
event
of
whole
genome
duplication
during
their
evolutionary
history.
Consequently,
large
range
plants,
including
many
the
world's
crops,
combines
more
than
two
sets
chromosomes
originating
from
same
(autopolyploids)
or
related
species
(allopolyploids).
Depending
on
polyploid
formation
pathway,
different
patterns
recombination
will
be
promoted,
conditioning
level
heterozygosity.
A
population
harboring
high
heterozygosity
produce
genetically
diverse
progenies.
Some
these
individuals
may
show
better
adaptability
to
ecological
niches,
increasing
chance
for
successful
establishment
through
natural
selection.
Another
condition
young
polyploids
survive
corresponds
well-balanced
gametes,
assuring
sufficient
fertility.
In
this
review,
we
discuss
consequences
pathways,
meiotic
behavior
and
regulation
speciation
success
maintenance
species.
PLoS Genetics,
Journal Year:
2019,
Volume and Issue:
15(4), P. e1008093 - e1008093
Published: April 22, 2019
Chromosome
and
genome
stability
are
important
for
normal
cell
function
as
instability
often
correlates
with
disease
dysfunction
of
DNA
repair
mechanisms.
Many
organisms
maintain
supernumerary
or
accessory
chromosomes
that
deviate
from
standard
chromosomes.
The
pathogenic
fungus
Zymoseptoria
tritici
has
many
eight
chromosomes,
which
highly
unstable
during
meiosis
mitosis,
transcriptionally
repressed,
show
enrichment
repetitive
elements,
heterochromatic
histone
methylation
marks,
e.g.,
trimethylation
H3
lysine
9
27
(H3K9me3,
H3K27me3).
To
elucidate
the
role
heterochromatin
on
in
Z.
tritici,
we
deleted
genes
encoding
methyltransferases
responsible
H3K9me3
H3K27me3,
kmt1
kmt6,
respectively,
generated
a
double
mutant.
We
combined
experimental
evolution
genomic
analyses
to
determine
impact
these
deletions
chromosome
stability,
both
vitro
planta.
used
whole
sequencing,
ChIP-seq,
RNA-seq
compare
changes
chromatin
structure,
differences
gene
expression
between
mutant
wildtype
strains.
Analyses
ChIP-seq
data
H3K9me3-deficient
strains
revealed
dramatic
reorganization,
where
H3K27me3
is
mostly
relocalized
into
regions
enriched
wild
type.
rearrangements
formation
new
were
found
absence
H3K9me3,
accompanied
by
activation
transposable
elements.
In
stark
contrast,
loss
actually
increased
under
growth
conditions
vitro,
even
without
large
scale
activity.
conclude
maintenance
because
it
disallows
considered
constitutive
heterochromatin.
this
system,
reduces
overall
generating
"metastable"
state
quasi-essential
genome.