Genomic insights into evolution of parthenogenesis and triploidy in the flowerpot snake
Science Advances,
Journal Year:
2025,
Volume and Issue:
11(14)
Published: April 2, 2025
The
flowerpot
snake
(
Indotyphlops
braminus
)
is
the
only
known
parthenogenetic
and
triploid
species
within
Serpentes.
However,
genetic
basis
underlying
this
phenomenon
remains
unresolved.
We
investigated
genomic
complexities
of
rare
all-female
reptile.
On
newly
assembled
genome,
we
revealed
40
chromosomes
grouped
into
three
subgenomes
(A,
B,
C).
Comparative
analysis
with
related
diploid
a
chromosome
fusion
event
in
ancestral
genomes.
This
shaped
unique
landscape
snake.
examined
gene
expression
specificity
ovarian
tissues
identified
pathways
essential
for
DNA
replication
repair.
Our
findings
suggest
potential
mechanism
homologous
pairing
during
meiosis
allopolyploid
parthenogenesis.
research
provides
insights
evolutionary
adaptations
mechanisms
parthenogenesis
reptilian
species,
challenging
traditional
views
on
reproductive
strategies
evolution
asexual
organisms.
Language: Английский
Meiotic deviations and endoreplication lead to diploid oocytes in female hybrids between bighead catfish (Clarias macrocephalus) and North African catfish (Clarias gariepinus)
Frontiers in Cell and Developmental Biology,
Journal Year:
2024,
Volume and Issue:
12
Published: Aug. 23, 2024
Introduction
Reproductive
isolation
and
hybrid
sterility
are
mechanisms
that
maintain
the
genetic
integrity
of
species
prevent
introgression
heterospecific
genes.
However,
crosses
closely
related
can
lead
to
complex
evolution,
such
as
formation
all-female
lineages
reproduce
clonally.
Bighead
catfish
(
Clarias
macrocephalus
)
North
African
C.
gariepinus
diverged
40
million
years
ago.
They
cultivated
hybridized
in
Thailand
for
human
consumption.
Male
hybrids
sterile
due
genome-wide
chromosome
asynapsis
during
meiosis.
Although
female
sometimes
fertile,
their
configuration
meiosis
has
not
yet
been
studied.
Methods
We
analyzed
at
pachytene
(synaptonemal
complexes)
diplotene
(lampbrush
chromosomes),
using
immunostaining
detect
pairing
double-stranded
break
formation,
FISH
with
species-specific
satellite
DNAs
distinguish
parental
chromosomes.
Results
More
than
95%
oocytes
exhibited
catfish;
however,
they
were
able
progress
stage
form
mature
eggs.
The
remaining
underwent
premeiotic
endoreplication,
followed
by
synapsis
crossing
over
between
sister
chromosomes,
similar
known
clonal
fish
reptiles.
Discussion
occurrence
reproduction
suggests
a
unique
model
studying
gametogenic
alterations
caused
hybridization
potential
asexual
reproduction.
Our
results
further
support
view
certain
animals
relies
on
intrinsic
sexually
reproducing
species,
given
multiple
independent
origins
same
mechanism.
Language: Английский
Premeiotic endoreplication is the mechanism of obligate parthenogenesis in rock lizards of the genus Darevskia
Biology Letters,
Journal Year:
2024,
Volume and Issue:
20(9)
Published: Sept. 1, 2024
Among
vertebrates,
obligate
parthenogenesis
occurs
exclusively
in
squamate
reptiles.
Premeiotic
endoreplication
a
small
subset
of
developing
oocytes
has
been
documented
as
the
mechanism
production
unreduced
eggs
minutely
explored
parthenogenetic
lineages,
namely
teiids
and
geckos.
The
situation
lacertid
genus
Darevskia
discussed
for
decades.
Certain
observations
suggested
that
ploidy
level
is
restored
during
egg
formation
through
fusion
polar
body
nuclei
unisexualis
D.
armeniaca
.
In
this
study,
we
re-evaluated
hypothesis
by
studying
diplotene
chromosomes
adult
females
sexual
species
raddei
nairensis
parthenogens
armeniaca,
dahli
We
revealed
19
bivalents
38
diploid
parthenogens,
which
uncovers
premeiotic
non-reduced
females.
earlier
contradicting
reports
can
likely
be
attributed
to
difficulty
identifying
mispairing
pachytene,
fact
reptiles
relying
on
only
undergo
genome
doubling
overcome
pachytene
checkpoint.
This
study
highlights
co-option
escape
from
reproduction
all
independent
hybrid
origins
vertebrates
studied
date.
Language: Английский