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Research Project
RNA-SEQ APPLIED TO THE PEACOCK BLENNY SALARIA PAVO: UNVEILING THE GENE NETWORKS AND SIGNALLING PATHWAYS BEHIND PHENOTYPIC PLASTICITY IN A LITTORAL FISH
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Temporal variation in brain transcriptome is associated with the expression of female mimicry as a sequential male alternative reproductive tactic in fish
Publication . Cardoso, Sara D.; Gonçalves, David; Goesmann, Alexander; Canário, Adelino V. M.; Oliveira, Rui Filipe
Distinct patterns of gene expression often underlie intra- and inter-sexual differences, and the study of this set of co-regulated genes is essential to understand the emergence of complex behavioural phenotypes. Here, we describe the development of a de novo transcriptome and brain gene expression profiles of wild-caught peacock blenny, Salaria pavo, an intertidal fish with sex-role reversal in courtship behaviour (i.e. females are the courting sex) and sequential alternative reproductive tactics in males (i.e. larger and older nest-holder males and smaller and younger sneaker males occur). Sneakers mimic both female's courtship behaviour and nuptial colouration to get access to nests and sneak fertilizations, and later in life transition into nest-holder males. Thus, this species offers the unique opportunity to study how the regulation of gene expression can contribute to intersex phenotypes and to the sequential expression of male and female behavioural phenotypes by the same individual. We found that at the whole brain level, expression of the sneaker tactic was paralleled by broader and divergent gene expression when compared to either females or nest-holder males, which were more similar between themselves. When looking at sex-biased transcripts, sneaker males are intersex rather than being either nest-holder or female-like, and their transcriptome is simultaneously demasculinized for nest-holder-biased transcripts and feminized for female-biased transcripts. These results indicate that evolutionary changes in reproductive plasticity can be achieved through regulation of gene expression, and in particular by varying the magnitude of expression of sex-biased genes, throughout the lifetime of the same individual.
Neurogenomic mechanisms of social plasticity
Publication . Cardoso, Sara D.; Teles, Magda; Oliveira, Rui Filipe
Group-living animals must adjust the expression of their social
behaviour to changes in their social environment and to transitions
between life-history stages, and this social plasticity can be seen as
an adaptive trait that can be under positive selection when changes
in the environment outpace the rate of genetic evolutionary change.
Here, we propose a conceptual framework for understanding the
neuromolecular mechanisms of social plasticity. According to this
framework, social plasticity is achieved by rewiring or by
biochemically switching nodes of a neural network underlying social
behaviour in response to perceived social information. Therefore, at
the molecular level, it depends on the social regulation of gene
expression, so that different genomic and epigenetic states of this
brain network correspond to different behavioural states, and the
switches between states are orchestrated by signalling pathways that
interface the social environment and the genotype. Different types of
social plasticity can be recognized based on the observed patterns
of inter- versus intra-individual occurrence, time scale and
reversibility. It is proposed that these different types of social plasticity
rely on different proximate mechanisms at the physiological, neural
and genomic level.
Social network predicts loss of fertilizations in nesting males of a fish with alternative reproductive tactics
Publication . Cardoso, Sara D.; Faustino, Ana Isabel Soares; Costa, Silvia S.; Valério, Fábio; Gonçalves, David; Oliveira, Rui Filipe
Alternative reproductive tactics (ARTs) evolve when
there is strong intra-sexual competition between conspecifics
for access to mates. Typically, larger Bbourgeois^ males reproduce
by securing the access to reproductive resources while
smaller Bparasitic^ males reproduce by stealing fertilizations
from larger males. A number of factors can influence the reproductive
success of each tactic, including intrinsic (e.g. size) and
extrinsic (e.g. tactic relative frequency) variables. An example
where plastic ARTs occur is the peacock blenny Salaria pavo,
with large males reproducing by defending nests and attracting
females (bourgeois tactic) and small males reproducing by
achieving sneaked fertilizations (parasitic tactic). In this study,
we conducted field observations on individually tagged animals
to determine their social network and collected eggs from 11
nests to determine the fertilization success of each male tactic.
Paternity estimates for 550 offspring indicated an average fertilization
success for nest-holder males of 95%. Nest-holder
male morphological traits and social network parameters were
tested as predictors of fertilization success, but only the number
of sneakers present in the nest-holder’s social networks was
found to be a predictor of paternity loss. Although male morphological
traits had been previously found to be strongly correlated
with reproductive success of nest-holder males, as measured
by the number of eggs collected in the male’s nest, no
correlation was found between any of the measured morphological
traits and fertilization success for these males. The results
suggest a stronger influence of the social environment than
of morphological variables in the proportion of lost fertilizations
by nest-holder males of this species.
Temporal variation in brain transcriptome is associated with the expression of female mimicry as a sequential male alternative reproductive tactic in fish
Publication . Cardoso, Sara; Gonçalves, David; Goesmann, Alexander; Canário, Adelino V. M.; Oliveira, Rui Filipe
Distinct patterns of gene expression often underlie intra- and intersexual differences, and the study of this set of coregulated genes is essential to understand the emergence of complex behavioural phenotypes. Here, we describe the development of a de novo transcriptome and brain gene expression profiles of wild-caught peacock blenny, Salaria pavo, an intertidal fish with sex-role reversal in courtship behaviour (i.e., females are the courting sex) and sequential alternative reproductive tactics in males (i.e., larger and older nest-holder males and smaller and younger sneaker males occur). Sneakers mimic both female's courtship behaviour and nuptial coloration to get access to nests and sneak fertilizations, and later in life transition into nest-holder males. Thus, this species offers the unique opportunity to study how the regulation of gene expression can contribute to intersex phenotypes and to the sequential expression of male and female behavioural phenotypes by the same individual. We found that at the whole brain level, expression of the sneaker tactic was paralleled by broader and divergent gene expression when compared to either females or nest-holder males, which were more similar between themselves. When looking at sex-biased transcripts, sneaker males are intersex rather than being either nest-holder or female-like, and their transcriptome is simultaneously demasculinized for nest-holder-biased transcripts and feminized for female-biased transcripts. These results indicate that evolutionary changes in reproductive plasticity can be achieved through regulation of gene expression, and in particular by varying the magnitude of expression of sex-biased genes, throughout the lifetime of the same individual.
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Funding agency
Fundação para a Ciência e a Tecnologia
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Funding Award Number
SFRH/BD/89072/2012