Chromosome
structure
is
complex,
and
many
aspects
of
its
organization
remain
poorly
understood.
Measuring
chromosome
stiffness
offers
valuable
insight
into
their
structural
properties.
In
this
study,
we
analyzed
the
chromosomes
from
metaphase
I
(MI)
II
(MII)
oocytes.
Our
results
revealed
a
ten-fold
increase
in
(Young’s
modulus)
MI
compared
to
somatic
chromosomes.
Furthermore,
MII
was
lower
than
that
We
examined
role
meiosis-specific
cohesin
complexes
regulating
stiffness.
Surprisingly,
three
mutants
exhibited
comparable
wild-type
chromosomes,
indicating
these
cohesins
are
not
primary
determinants
Additionally,
our
findings
an
age-related
Since
aging
associated
with
elevated
levels
DNA
damage,
investigated
impact
etoposide-induced
damage
on
oocyte
found
it
led
reduction
Overall,
study
underscores
dynamic
cyclical
nature
stiffness,
modulated
by
both
cell
cycle
factors.
Human
recombination
maps
are
a
valuable
resource
for
association
and
linkage
studies
crucial
many
inferences
of
population
history
natural
selection.
Existing
maps1-5
based
solely
on
cross-over
(CO)
recombination,
omitting
non-cross-overs
(NCOs)-the
more
common
form
recombination6-owing
to
the
difficulty
in
detecting
them.
Using
whole-genome
sequence
data
families,
we
estimate
number
NCOs
transmitted
from
parent
offspring
derive
complete,
sex-specific
including
both
COs.
Mothers
have
fewer
but
longer
than
fathers,
oocytes
accumulate
non-regulated
fashion
with
maternal
age.
Recombination,
primarily
NCO,
is
responsible
1.8%
(95%
confidence
interval:
1.3-2.3)
11.3%
9.0-13.6)
paternal
de
novo
mutations,
respectively,
may
drive
increase
mutations
substantially
prominent
COs
centromeres,
possibly
avoid
large-scale
genomic
changes
that
cause
aneuploidy.
Our
results
demonstrate
highlight
much
greater
extent
differences
meiotic
process
between
sexes,
which
reflect
safeguarding
infancy
until
ovulation.
PLoS Biology,
Год журнала:
2025,
Номер
23(1), С. e3002950 - e3002950
Опубликована: Янв. 6, 2025
In
many
eukaryotes,
meiotic
recombination
occurs
preferentially
at
discrete
sites,
called
hotspots.
various
lineages,
hotspots
are
located
in
regions
with
promoter-like
features
and
evolutionarily
stable.
Conversely,
some
mammals,
driven
by
PRDM9
that
targets
away
from
promoters.
Paradoxically,
induces
the
self-destruction
of
its
this
triggers
an
ultra-fast
evolution
mammalian
is
ancestral
to
all
animals,
suggesting
a
critical
importance
for
program,
but
has
been
lost
lineages
surprisingly
little
effect
on
meiosis
success.
However,
it
unclear
whether
function
described
mammals
shared
other
species.
To
investigate
this,
we
analyzed
landscape
several
salmonids,
genome
which
harbors
one
full-length
truncated
paralogs.
We
identified
initiation
sites
Oncorhynchus
mykiss
mapping
DNA
double-strand
breaks
(DSBs).
found
DSBs
clustered
positioned
promoters,
enriched
H3K4me3
H3K36me3
location
depended
genotype
Prdm9
.
observed
high
level
polymorphism
zinc
finger
domain
,
indicating
diversification
positive
selection.
Moreover,
population-scaled
maps
O
kisutch
Salmo
salar
revealed
rapid
turnover
caused
target
motif
erosion.
Our
results
imply
conserved
across
vertebrates
peculiar
evolutionary
runaway
active
hundred
million
years.
Proceedings of the National Academy of Sciences,
Год журнала:
2025,
Номер
122(2)
Опубликована: Янв. 6, 2025
During
meiosis,
each
pair
of
homologous
chromosomes
becomes
connected
by
at
least
one
crossover,
as
required
for
accurate
segregation,
and
adjacent
crossovers
are
widely
separated
thereby
limiting
total
numbers.
In
coarsening
models,
this
crossover
patterning
results
from
nascent
recombination
sites
competing
to
accrue
a
pro-crossover
RING-domain
protein
(COR)
that
diffuses
between
synapsed
chromosomes.
Here,
we
delineate
the
localization
dynamics
three
mammalian
CORs
in
mouse
determine
their
interdependencies.
RNF212,
HEI10,
newest
member
RNF212B
show
divergent
spatiotemporal
along
chromosomes,
including
profound
differences
spermatocytes
oocytes,
not
easily
reconciled
elementary
models.
Contrasting
mutant
phenotypes
genetic
requirements
indicate
RNF212B,
HEI10
play
distinct
but
interdependent
functions
regulating
meiotic
coordinating
events
prophase-I
integrating
signals
DNA
breaks,
homolog
synapsis,
cell-cycle,
incipient
sites.
During
meiosis,
the
parental
chromosomes
are
drawn
together
to
enable
exchange
of
genetic
information.
Chromosomes
aligned
through
assembly
a
conserved
interface,
synaptonemal
complex,
composed
central
region
that
forms
between
two
parallel
chromosomal
backbones
called
axes.
Here,
we
identify
axis-central
interface
in
C.
elegans
,
containing
positive
patch
on
axis
component
HIM-3
and
negative
C
terminus
protein
SYP-5.
Crucially,
canonical
ultrastructure
complex
is
altered
upon
weakening
this
using
charge-reversal
mutations.
We
developed
thermodynamic
model
recapitulates
our
experimental
observations,
indicating
liquid-like
can
assemble
by
wetting
axes
without
active
energy
consumption.
More
broadly,
data
show
condensation
drives
tightly
regulated
nuclear
reorganization
during
sexual
reproduction.
Chromosome
structure
is
complex,
and
many
aspects
of
chromosome
organization
are
still
not
understood.
Measuring
the
stiffness
chromosomes
offers
valuable
insight
into
their
structural
properties.
In
this
study,
we
analyzed
from
metaphase
I
(MI)
II
(MII)
oocytes.
Our
results
revealed
a
tenfold
increase
in
(Young’s
modulus)
MI
compared
to
somatic
chromosomes.
Furthermore,
MII
was
found
be
lower
than
that
We
examined
role
meiosis-specific
cohesin
complexes
regulating
stiffness.
Surprisingly,
three
mutants
did
significantly
differ
wild-type
chromosomes,
indicating
these
cohesins
may
primary
determinants
Additionally,
our
findings
an
age-related
for
Since
aging
associated
with
elevated
levels
DNA
damage,
investigated
impact
etoposide-induced
damage
on
it
led
reduction
Overall,
study
underscores
dynamic
cyclical
nature
stiffness,
modulated
by
both
cell
cycle
factors.
Current Opinion in Genetics & Development,
Год журнала:
2025,
Номер
93, С. 102349 - 102349
Опубликована: Апрель 17, 2025
The
synaptonemal
complex
(SC)
is
structurally
conserved
across
eukaryotes
and
essential
for
a
proper
progression
of
meiosis.
Despite
this
conservation,
SC
protein
sequences
diverge
drastically.
In
review,
we
explore
findings
on
evolution,
highlighting
key
differences
commonalities
among
lineages
like
the
Caenorhabditis
Drosophila
genera.
We
further
known
cases
where
its
proteins
adopt
novel
functional
roles
discuss
why
knowledge
these
could
be
important
study
canonical
biology.
existing
studies
demonstrate
that
work
evolutionary
biology
in
more
diverse
meiotic
research
organisms
should
play
major
role
aiding
our
understanding
structure
functions.
Current Opinion in Plant Biology,
Год журнала:
2024,
Номер
80, С. 102548 - 102548
Опубликована: Май 14, 2024
Heat
stress
is
one
of
the
major
constraints
to
plant
growth
and
fertility.
During
current
climate
crisis,
heat
waves
have
increased
dramatically,
even
more
extreme
conditions
are
predicted
for
near
future,
considerably
affecting
ecosystems
seriously
threatening
world
food
security.
Although
very
well
known
affect
especially
reproductive
structures,
little
about
how
interferes
with
reproduction
in
comparison
somatic
cells
tissues.
Recently,
effect
on
meiosis
as
a
central
process
sexual
has
been
analyzed
molecular
cytological
depth.
Notably,
these
studies
not
only
important
applied
research
by
laying
foundation
breeding
heat-resilient
crops,
but
also
fundamental
research,
revealing
general
regulatory
mechanisms
recombination
chromosome
segregation
control.
Biochemical Society Transactions,
Год журнала:
2024,
Номер
52(1), С. 379 - 393
Опубликована: Фев. 13, 2024
Meiotic
recombination,
a
cornerstone
of
eukaryotic
diversity
and
individual
genetic
identity,
is
essential
for
the
creation
physical
linkages
between
homologous
chromosomes,
facilitating
their
faithful
segregation
during
meiosis
I.
This
process
requires
that
germ
cells
generate
controlled
DNA
lesions
within
own
genome
are
subsequently
repaired
in
specialised
manner.
Repair
these
breaks
involves
modulation
existing
recombination
repair
pathways
to
crossovers
chromosomes.
Decades
cytological
studies
have
identified
multitude
factors
involved
meiotic
recombination.
Recent
work
has
started
provide
additional
mechanistic
insights
into
how
interact
with
one
another,
DNA,
molecular
outcomes
required
successful
meiosis.
Here,
we
review
recent
developments
focus
on
protein
structures
protein-protein
interactions.
