BMC Genomics,
Journal Year:
2024,
Volume and Issue:
25(1)
Published: Nov. 20, 2024
Abstract
Background
The
short-snout
icefish,
Neosalanx
brevirostris
,
a
member
of
the
Salangidae
family,
is
an
economically
important
fishery
species
in
China.
Understanding
mechanisms
underlying
sex
determination
this
has
crucial
implications
for
conservation,
ecology
and
evolution.
Meanwhile,
there
shortage
rapid
cost-effective
genetic
methods
identification,
which
poses
challenges
identifying
immature
individuals
mechanism
studies
aquaculture
breeding
applications.
Results
Based
on
whole
genome
resequencing
data,
sex-specific
loci
regions
were
found
to
be
concentrated
region
chromosome
2.
All
exhibited
excess
heterozygosity
females
complete
homozygosity
males.
This
determining
contains
seven
genes,
including
cytochrome
P450
aromatase
CYP19B
involved
steroidogenesis
associated
with
24
two
W-deletions.
A
haploid
female-specific
sequence
was
identified
as
paralogous
diploid
significant
length
difference,
making
it
suitable
identification
by
traditional
PCR
agarose
gel
electrophoresis,
further
validated
males
known
phenotypic
sexes.
Conclusions
Our
results
confirm
that
N.
exhibits
female
heterogametic
system
(ZZ/ZW),
2
putative
containing
relatively
small
(~
48
Kb).
gene
proposed
candidate
gene.
Moreover,
development
based
method
enables
at
any
developmental
stage,
thereby
facilitating
advancing
applications
species.
Annual Review of Animal Biosciences,
Journal Year:
2023,
Volume and Issue:
12(1), P. 233 - 259
Published: Oct. 20, 2023
Sexual
reproduction
is
prevalent
across
diverse
taxa.
However,
sex-determination
mechanisms
are
so
that
even
closely
related
species
often
differ
in
systems.
Teleost
fish
a
taxonomic
group
with
frequent
turnovers
of
sex-determining
and
thus
provides
us
great
opportunities
to
investigate
the
molecular
evolutionary
underlying
turnover
Here,
we
compile
recent
studies
on
diversity
fish.
We
demonstrate
genes
TGF-β
signaling
pathway
frequently
used
for
master
(MSD)
genes.
MSD
arise
via
two
main
mechanisms,
duplication-and-transposition
allelic
mutations,
few
exceptions.
also
temperature
influences
sex
determination
many
species,
those
chromosomes,
higher
temperatures
inducing
differentiation
into
males
most
cases.
Finally,
review
theoretical
models
discuss
what
questions
remain
elusive.
Molecular Ecology Resources,
Journal Year:
2023,
Volume and Issue:
23(4), P. 886 - 904
Published: Jan. 1, 2023
Sex
determination
(SD)
shows
huge
variation
among
fish
and
a
high
evolutionary
rate,
as
illustrated
by
the
Pleuronectiformes
(flatfishes).
This
order
is
characterized
its
adaptation
to
demersal
life,
compact
genomes
diversity
of
SD
mechanisms.
Here,
we
assembled
Solea
senegalensis
genome,
flatfish
great
commercial
value,
into
82
contigs
(614
Mb)
combining
long-
short-read
sequencing,
which
were
next
scaffolded
using
highly
dense
genetic
map
(28,838
markers,
21
linkage
groups),
representing
98.9%
assembly.
Further,
established
correspondence
between
assembly
chromosomes
BAC-FISH.
Whole
genome
resequencing
six
males
females
enabled
identification
41
single
nucleotide
polymorphism
variants
in
follicle
stimulating
hormone
receptor
(fshr)
consistent
with
an
XX/XY
system.
The
observed
sex
association
was
validated
broader
independent
sample,
providing
novel
molecular
sexing
tool.
fshr
gene
displayed
differential
expression
male
female
gonads
from
86
days
post-fertilization,
when
gonad
still
undifferentiated
primordium,
concomitant
activation
amh
cyp19a1a,
testis
ovary
marker
genes,
respectively,
females.
Y-linked
allele,
included
24
nonsynonymous
showed
divergent
3D
protein
structure,
overexpressed
compared
X-linked
allele
at
all
stages
gonadal
differentiation.
We
hypothesize
mechanism
hampering
action
driving
toward
testis.
International Journal of Molecular Sciences,
Journal Year:
2023,
Volume and Issue:
24(3), P. 2468 - 2468
Published: Jan. 27, 2023
In
vertebrates,
mainly
single
genes
with
an
allele
ratio
of
1:1
trigger
sex-determination
(SD),
leading
to
initial
equal
sex-ratios.
Such
are
designated
master-key
regulators
(MKRs)
and
frequently
associated
DNA
structural
variations,
such
as
copy-number
variation
null-alleles.
Most
MKR
knowledge
comes
from
fish,
especially
cichlids,
which
serve
a
genetic
model
for
SD.
We
list
14
MKRs,
dmrt1
has
been
identified
in
taxonomically
distant
species
birds
fish.
The
identification
MKRs
known
involvement
SD,
amh
fshr,
indicates
that
common
network
drives
illustrate
affects
estrogen/androgen
equilibrium,
suggesting
may
exert
over-expression
the
gene
thus
form
MKR.
However,
reason
why
certain
factors
constitute
whereas
others
do
not
is
unclear.
limited
number
conserved
suggests
their
heterologous
sequences
could
be
used
targets
future
searches
additional
species.
Sex-specific
mortality,
sex
reversal,
role
temperature
multigenic
SD
examined,
claiming
these
phenomena
often
consequences
artificial
hybridization.
discuss
essentiality
taxonomic
authentication
validate
purebred
origin
before
searches.
Journal of Evolutionary Biology,
Journal Year:
2023,
Volume and Issue:
36(3), P. 632 - 636
Published: Jan. 22, 2023
Sex
chromosomes
either
carry
a
factor
like
the
male-determining
factors
of
mammals
(Berta
et
al.,
1990)
or
plant
Silene
latifolia
(Westergaard,
1958),
function
in
balanced
sex-determining
systems,
as
Drosophila
(Bridges,
1925)
and
Caenorhabditis
elegans
(Meyer,
2022).
The
sex
chromosome
pairs
these
several
other
species
include
physically
extensive
fully
Y-linked,
male-specific,
regions
('MSY')
that
have
undergone
'genetic
degeneration'
lost
most
genes
are
carried
on
X
(X-linked
then
hemizygous
males).
Similar
losses
recombination,
similar
degeneration,
occurred
evolution
with
female
heterogamety,
including
birds
Lepidoptera,
respectively,
reviewed
by
Wang
al.
(2014)
Fraisse
(2017).
lack
recombination
is
probably
not
direct
consequence
carrying
genes,
having
an
essential
role
determination,
since
unrelated
fish
small
located
within
recombining
(Koyama
2019;
Kuhl
2021;
Nacif
2022;
Reichwald
2015),
completely
sex-linked
some
plants
smaller
than
1
Mb
(Akagi
2014;
Harkess
2020).
These
situations
can
be
explained
ways,
for
example
they
could
reflect
recent
separate
sexes,
appearance
genome
region
so-called
turnover
event
(Vicoso,
2019).
Species
whose
pair
has
changes
which
formerly
stopped
previously
established
therefore
important,
because
tell
us
became
suppressed
after
their
locus
evolved.
first
case
to
discovered
was
Eutherian
mammals.
earliest
enlargement
MSY
involved
fusion
Y
chromosome,
autosome
Marsupials
(Waters
2001).
This
around
115
million
years
ago
(Cortez
2014).
Further
enlargements
caused
subsequent
suppression
events
produced
'evolutionary
strata'
wide
differences
sequence
divergence
between
Y-X
different
(Figure
1).
Based
genetic
map
estimated
females
(which
represents
ancestral
order
added
chromosome),
recently
near
still
recombines,
pseudo-autosomal
region,
'PAR'
(Lahn
&
Page,
1999;
Skaletsky
2003).
In
two
evolved
strata
humans,
median
synonymous
site
values
14%
26%,
almost
high
rest
(Sayres
Makova,
2013).
Very
varied
divergence,
perhaps
reflecting
strata,
also
seen
latifolia,
carnation
family
(Bergero
2007;
Papadopulos
2015).
threespine
stickleback,
without
fusions
any
autosomes,
shows
clear
Figure
1b
(Peichel
2020),
been
inferred
ZW
Neognathous
(Wang
A
may
always
such
(Charlesworth,
However,
cases
when
(shrinking
PAR
changing
its
boundary
region)
demand
explanation.
Several
hypotheses
proposed.
One
idea
sexually
antagonistic
polymorphisms
become
(e.g.
male-benefit
allele
would
reduce
fitness
more
likely
spread
if
closely
linked
one
same
effects
autosomal).
Should
mutation
establish
polymorphism,
this
generates
selection
closer
linkage
(Rice,
1987).
difficult
test
because,
non-recombining
stratum
evolved,
will
present
only
Y-linked
making
analysis
impossible.
Although
mutations
might
detectable
from
expression
sexes
at
(perhaps
higher
males),
degeneration
expected
eventually
old
evolutionary
strata.
Another
approach
population
genomic
evidence
show
associations
alleles
(Dagilis
Qiu
signal
found
partially
it
does
whether
future
lead
recombination.
search
alternatives
explain
ask
ruled
out.
As
described
below,
new
ideas
Testing
predictions
2
below)
requires
studies
newly
evolving
genomes,
becoming
possible,
using
combination
sequencing
mapping.
study
S.
dioica
(closely
related
hybridize
nature
homologous
XY
chromosomes),
published
Journal
Evolutionary
Biology
(Filatov,
2022),
examines
stratum.
Y-
X-linked
nevertheless
ascertained
identifying
male-specific
variants
gene
sequences,
samples
males
natural
populations.
allowed
analyses
mentioned
above
showed
parts
establishment
factor.
Clear
step
those
seen,
numbers
unknown,
species'
genomes
large
human
yet
assembled.
mapping
suggest
extremely
rate
PAR,
thus
differ
mammalian
PARs,
crossover
concentrated
very
(Rouyer
1986).
Some
but
dioica,
suggesting
(and
dioica;
Campos
2016).
end
studied
them
detail.
22
were
both
(they
had
populations),
20
classified
species,
15
appear
forming
young
(much
younger
youngest
ones
humans
above)
suitable
testing
about
suppression.
(MSY)
gradually
expand
hinders
pairing
sequences
meiosis
(Jeffries
2021).
MSY-X
should
increase
distance
into
2).
slight
trend
stratum,
outgroup
vulgaris
increases
so
responsible
(HKA
tests,
correct
effect,
detected
elevated
diversity
suggests
regions).
Interestingly,
sharply
latifolia-specific
shared
change
possibly
discontinuous
1b.
time
makes
seem
unlikely
loss
expansion
across
includes
least
(probably
500
kb,
density
34
genes/Mb).
stickleback
slightly
(Ks),
3%
4%,
Again
Ks
older
predicted.
true
papaya,
2012),
consistent
chromosomal
inversion
models
propose
expansions
involving
chance
inversions
prevent
set
MSY.
advantage
outweigh
fertility
disadvantages
heterozygotes,
production
gametes
duplications
deficiencies
crossovers
occur
paired
inversions.
version
(Jay
Olito
2022)
proposes
prevents
deleterious
homozygous
males.
effect
strongest
highly
recessive
effects.
Accumulation
arises
fixing
population,
must
rapidly
replace
(initially
arrangement).
process
works
best
populations,
account
observations
time-course
formation.
involved,
data
distinguish
previous
one—both
predict
current
boundary.
Only
few
examples
coinciding
boundaries
far
discovered.
inversions,
others
done
(Lemaitre
2009).
cases,
(10
IV
seven
V),
formation
require
genes.
(involving
16
genes)
papaya
2012).
Clearly,
detailed
helpful.
rearrangements,
accumulate
stops
(Charlesworth
1994),
third
model
decrease
expression,
dosage
compensation
simultaneously
alleles'
even
before
major
deterioration
coding
reverting
standard
arrangement
(Lenormand
Roze,
Female-biased
indeed
observed
assumed
decreased
alleles,
while
increased
enough
restore
predicts
bias
quickly
sex-linkage
evolves.
Because
evolves
part
process,
strongly
female-biased
many
older)
sexes.
appears
opposite
way
increasing
reach
level
(in
double
males,
significant
difference
which,
expected,
little
bias).
(reviewed
Bachtrog,
2008).
Genes
compensated
seems
incomplete
It
interesting
already
begun
studied,
well
ones,
percent.
Under
polymorphism
hypothesis
outlined
above,
expect
gene(s)
often
pattern
predicted
just
described),
Overall,
model,
do
fit
observations.
Filatov's
larger
supports
(using
HKA
differences),
variants.
Whether
conclusions
confirmed
once
assembly
becomes
available,
valuable
how
integrated
increasingly
accessible
kinds
allow
empirical
tests
this,
potentially
For
instance,
compared
somatic
tissues,
over-represented
among
biased
155
47
one,
did
relationship
genes'
positions
(Kitano
peer
review
history
article
available
https://publons.com/publon/10.1111/jeb.14137.
commentary
there
no
data.
BMC Biology,
Journal Year:
2025,
Volume and Issue:
23(1)
Published: Feb. 21, 2025
Sex
chromosome
(SC)
evolution
is
a
longstanding
topic
of
focus
in
evolutionary
biology.
Teleosts
often
exhibit
rapid
turnover
SCs
and
sex-determining
(SD)
genes,
alongside
diverse
range
SC
differentiation
mechanisms.
On
the
basis
new
chromosome-scale
assemblies
three
Silurus
species
(S.
microdorsalis,
S.
glanis,
lanzhouensis)
two
outgroup
(Pterocryptis
cochinchinensis
Kryptopterus
bicirrhis),
along
with
our
previous
meridionalis
asotus,
we
traced
genus
(Siluriformes),
following
fate
known
SD
gene
amhr2y.
Phylogenetic
analysis
showed
that
amhr2y
occurred
at
least
before
divergence
Pterocryptis,
Kryptopterus,
lost
P.
K.
bicirrhis.
Chr24
has
become
ancestor
five
due
to
duplication-and-translocation
amhr2
mediated
by
LTR
transposon.
Then,
proto
Y
was
formed
maintained
shared
60
kb
male-specific
region
(MSY)
transposable
elements
(TEs)
expansion
gathering.
Due
continuous
TEs
accumulation,
genes
other
than
MSYs
have
degenerated
or
been
lost,
while
non-recombinant
regions
continue
expend,
forming
different
sizes
(from
320
550
kb).
Two
events,
one
homologous
left
arm
right
Chr24)
nonhomologous
Chr5),
occurring
among
were
possibly
hAT
Helitron
transposons.
Our
results
on
dynamic
trajectory
amhr2y,
MSYs,
catfish
indicated
variability
diversity
fish
confirmed
frequent
an
important
way
maintain
homology
low
SCs.
International Journal of Molecular Sciences,
Journal Year:
2025,
Volume and Issue:
26(7), P. 3282 - 3282
Published: April 1, 2025
The
canonical
model
of
vertebrate
sex
chromosome
evolution
predicts
a
one-way
trend
toward
degradation.
However,
most
chromosomes
in
lower
vertebrates
are
homomorphic.
Recent
progress
studies
determination
has
resulted
the
discovery
more
than
30
master
(MSD)
genes,
which
from
teleost
fish.
An
analysis
MSD
gene
acquisition,
recombination
suppression,
and
chromosome-specific
sequences
revealed
correlations
modes
acquisition
chromosomes.
Sex
remain
homomorphic
with
genes
acquired
by
simple
mutations,
duplications,
allelic
variations,
or
neofunctionalization;
contrast,
they
become
heteromorphic
chromosomal
inversion,
fusion,
fission.
There
is
no
suppression
carrying
gained
through
mutations.
In
there
extensive
inversion.
limited
transposition
translocation.
We
propose
cause-effect
that
as
consequence
explains
various
vertebrates.
A
key
factor
determining
whether
non-homologous
regions
created
during
genes.
Chromosome
inversion
creates
inversely
homologous
but
directly
sequences,
lead
to
retain
potential.
Over
time,
recurrent
inverted
leads
formation
strata
may
cause
degradation
Depending
on
nature
deletions
regions,
evolve
dosage
compensation,
selective
retention
haplo-insufficient
be
used
an
alternative
strategy.
Scientific Reports,
Journal Year:
2024,
Volume and Issue:
14(1)
Published: Jan. 30, 2024
Sex
chromosome
replacement
is
frequent
in
many
vertebrate
clades,
including
fish,
frogs,
and
lizards.
In
order
to
understand
the
mechanisms
responsible
for
sex
turnover
early
stages
of
divergence,
it
necessary
study
lineages
with
recently
evolved
chromosomes.
Here
we
examine
evolution
a
group
African
cichlid
fishes
(tribe
Tropheini)
which
began
diverge
from
one
another
less
than
4
MYA.
We
have
evidence
previously
unknown
system,
preliminary
indications
several
additional
systems
not
reported
this
group.
find
high
frequency
estimate
minimum
14
turnovers
tribe.
date
origin
most
common
determining
system
tribe
(XY-LG5/19)
near
base
two
major
sub-clades
tribe,
about
3.4
MY
ago.
Finally,
observe
variation
size
sex-determining
region
that
suggests
independent
evolutionary
strata
species
shared
sex-determination
system.
Our
results
illuminate
rapid
rate
Tropheini
set
stage
further
studies
dynamics