scholarly journals Sex-biased gene expression in rhesus macaque and human brains

2020 ◽  
Author(s):  
Alex R. DeCasien ◽  
Chet C. Sherwood ◽  
James P. Higham
Keyword(s):  
Gene Expression ◽  
Sex Differences ◽  
Sexual Selection ◽  
Cognitive Abilities ◽  
Rhesus Macaques ◽  
Purifying Selection ◽  
Brain Regions ◽  
Sexually Dimorphic ◽  
Brain Gene Expression ◽  
Human Brains

AbstractSexually dimorphic traits (i.e. phenotypic differences between males and females) are largely produced by sex-biased gene expression (i.e. differential expression of genes present in both sexes). These expression differences may be the result of sexual selection, although other factors (e.g., relaxed purifying selection, pleiotropy, dosage compensation) also contribute. Given that humans and other primates exhibit sex differences in cognition and neuroanatomy, this implicates sex differences in brain gene expression. Here, we compare sex-biased gene expression in humans and rhesus macaques across 16 brain regions using published RNA-Seq datasets. Our results demonstrate that most sex-biased genes are differentially expressed between species, and that overlap across species is limited. Human brains are relatively more sexually dimorphic and exhibit more male-than female-biased genes. Across species, gene expression is biased in opposite directions in some regions and in the same direction in others, suggesting that the latter may be more relevant in nonhuman primate models of neurological disorders. Finally, the brains of both species exhibit positive correlations between sex effects across regions, higher tissue specificity among sex-biased genes, enrichment of extracellular matrix among male-biased genes, and regulation of sex-biased genes by sex hormones. Taken together, our results demonstrate some conserved mechanisms underlying sex-biased brain gene expression, while also suggesting that increased neurodevelopmental plasticity and/or strong sexual selection on cognitive abilities may have played a role in shaping sex-biased brain gene expression in the human lineage.

scholarly journals Impact of male trait exaggeration on sex-biased gene expression and genome architecture in a water strider

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
William Toubiana ◽  
David Armisén ◽  
Corentin Dechaud ◽  
Roberto Arbore ◽  
Abderrahman Khila
Keyword(s):  
Gene Expression ◽  
Sexual Selection ◽  
Enrichment Analysis ◽  
Purifying Selection ◽  
Genome Architecture ◽  
Water Strider ◽  
Secondary Sexual Traits ◽  
Genomic Regions ◽  
Small Clusters ◽  
Secondary Sexual

Abstract Background Exaggerated secondary sexual traits are widespread in nature and often evolve under strong directional sexual selection. Although heavily studied from both theoretical and empirical viewpoints, we have little understanding of how sexual selection influences sex-biased gene regulation during the development of exaggerated secondary sexual phenotypes, and how these changes are reflected in genomic architecture. This is primarily due to the limited availability of representative genomes and associated tissue and sex transcriptomes to study the development of these traits. Here we present the genome and developmental transcriptomes, focused on the legs, of the water strider Microvelia longipes, a species where males exhibit strikingly long third legs compared to females, which they use as weapons. Results We generated a high-quality genome assembly with 90% of the sequence captured in 13 scaffolds. The most exaggerated legs in males were particularly enriched in both sex-biased and leg-biased genes, indicating a specific signature of gene expression in association with trait exaggeration. We also found that male-biased genes showed patterns of fast evolution compared to non-biased and female-biased genes, indicative of directional or relaxed purifying selection. By contrast to male-biased genes, female-biased genes that are expressed in the third legs, but not the other legs, are over-represented in the X chromosome compared to the autosomes. An enrichment analysis for sex-biased genes along the chromosomes revealed also that they arrange in large genomic regions or in small clusters of two to four consecutive genes. The number and expression of these enriched regions were often associated with the exaggerated legs of males, suggesting a pattern of common regulation through genomic proximity in association with trait exaggeration. Conclusion Our findings indicate how directional sexual selection may drive sex-biased gene expression and genome architecture along the path to trait exaggeration and sexual dimorphism.

72 EXPLORATORY ANALYSIS OF SEX DIFFERENCES IN BRAIN GENE EXPRESSION IN SUICIDES

2019 ◽  
Vol 29 ◽  
pp. S100
Author(s):  
Brenda Cabrera ◽  
Nancy Monroy ◽  
Cristóbal Fresno ◽  
Consuelo Walss-Bass ◽  
Gabriel Fries ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Differences ◽  
Exploratory Analysis ◽  
Brain Gene Expression

scholarly journals Inter- and Intraspecific Variation in Drosophila Genes with Sex-Biased Expression

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Lena Müller ◽  
Sonja Grath ◽  
Korbinian von Heckel ◽  
John Parsch
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Molecular Evolution ◽  
Protein Sequence ◽  
Sequence Variation ◽  
Purifying Selection ◽  
Sexually Dimorphic ◽  
Expression Divergence ◽  
Sexually Dimorphic Expression ◽  
Dimorphic Expression

Genes with sexually dimorphic expression (sex-biased genes) often evolve rapidly and are thought to make an important contribution to reproductive isolation between species. We examined the molecular evolution of sex-biased genes in Drosophila melanogaster and D. ananassae, which represent two independent lineages within the melanogaster group. We find that strong purifying selection limits protein sequence variation within species, but that a considerable fraction of divergence between species can be attributed to positive selection. In D. melanogaster, the proportion of adaptive substitutions between species is greatest for male-biased genes and is especially high for those on the X chromosome. In contrast, male-biased genes do not show unusually high variation within or between populations. A similar pattern is seen at the level of gene expression, where sex-biased genes show high expression divergence between species, but low divergence between populations. In D. ananassae, there is no increased rate of adaptation of male-biased genes, suggesting that the type or strength of selection acting on sex-biased genes differs between lineages.

scholarly journals Sex differences in gene expression and proliferation are dependent on the epigenetic modifier HP1γ

2019 ◽  
Author(s):  
Pui-Pik Law ◽  
Ping-Kei Chan ◽  
Kirsten McEwen ◽  
Huihan Zhi ◽  
Bing Liang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Differences ◽  
Sex Chromosome ◽  
Chromosome Complement ◽  
Autosomal Gene ◽  
Sexually Dimorphic ◽  
Heterochromatin Protein 1 ◽  
Epigenetic Modifier ◽  
Early Embryos ◽  
Males And Females

SummarySex differences in growth rate in very early embryos have been recognized in a variety of mammals and attributed to sex-chromosome complement effects as they occur before overt sexual differentiation. We previously found that sex-chromosome complement, rather than sex hormones regulates heterochromatin-mediated silencing of a transgene and autosomal gene expression in mice. Here, sex dimorphism in proliferation was investigated. We confirm that male embryonic fibroblasts proliferate faster than female fibroblasts and show that this proliferation advantage is completely dependent upon heterochromatin protein 1 gamma (HP1γ). To determine whether this sex-regulatory effect of HP1γ was a more general phenomenon, we performed RNA sequencing on MEFs derived from males and females, with or without HP1γ. Strikingly, HP1γ was found to be crucial for regulating nearly all sexually dimorphic autosomal gene expression because deletion of the HP1γ gene in males abolished sex differences in autosomal gene expression. The identification of a key epigenetic modifier as central in defining gene expression differences between males and females has important implications for understanding physiological sex differences and sex bias in disease.

scholarly journals Impact of trait exaggeration on sex-biased gene expression and genome architecture in a water strider

2020 ◽  
Author(s):  
William Toubiana ◽  
David Armisén ◽  
Corentin Dechaud ◽  
Roberto Arbore ◽  
Abderrahman Khila
Keyword(s):  
Gene Expression ◽  
Sexual Selection ◽  
Enrichment Analysis ◽  
Purifying Selection ◽  
Genome Architecture ◽  
Water Strider ◽  
Secondary Sexual Traits ◽  
Specific Trait ◽  
Sexual Traits ◽  
Secondary Sexual

AbstractExaggerated secondary sexual traits are widespread in nature and often evolve under strong directional sexual selection. Although heavily studied from both theoretical and empirical viewpoints, we have little understanding of how sexual selection influences sex-biased gene regulation during the development of sex-specific phenotypes, and how these changes are reflected in genomic architecture. This is primarily due to the lack of a representative genome and transcriptomes to study the development of secondary sexual traits. Here we present the genome and developmental transcriptomes, focused on the legs of the water strider Microvelia longipes, a species where males exhibit strikingly long third legs used as weapons. The quality of the genome assembly is such that over 90% of the sequence is captured in 13 scaffolds. The most exaggerated legs in males were particularly enriched in sex-biased genes, indicating a specific signature of gene expression in association with sex-specific trait exaggeration. We also found that male-biased genes showed patterns of fast evolution compared to non-biased and female-biased genes, indicative of directional or relaxed purifying selection. Interestingly, we found that female-biased genes that are expressed in the third legs only, but not male-biased genes, were over-represented in the X chromosome compared to the autosomes. An enrichment analysis for sex-biased genes along the chromosomes revealed that they can arrange in large genomic regions or in small clusters of two to four consecutive genes. The number and expression of these enriched regions were often associated with the exaggerated legs of males, suggesting a pattern of common regulation through genomic proximity in association with trait exaggeration. Our findings shed light on how directional sexual selection drives sex-biased gene expression and genome architecture along the path to trait exaggeration and sexual dimorphism.

Relative Cerebellum Size Is Not Sexually Dimorphic across Primates

2020 ◽  
Vol 95 (2) ◽  
pp. 93-101
Author(s):  
Alex R. DeCasien ◽  
James P. Higham
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Sex Difference ◽  
Cognitive Abilities ◽  
Relative Size ◽  
Brain Evolution ◽  
Primate Species ◽  
Published Data ◽  
Heterogeneous Structure ◽  
Selection Pressures

Background/Aims: Substantive sex differences in behavior and cognition are found in humans and other primates. However, potential sex differences in primate neuroanatomy remain largely unexplored. Here, we investigate sex differences in the relative size of the cerebellum, a region that has played a major role in primate brain evolution and that has been associated with cognitive abilities that may be subject to sexual selection in primates. Methods: We compiled individual volumetric and sex data from published data sources and used MCMC generalized linear mixed models to test for sex effects in relative cerebellar volume while controlling for phylogenetic relationships between species. Given that the cerebellum is a functionally heterogeneous structure involved in multiple complex cognitive processes that may be under selection in males or females within certain species, and that sexual selection pressures vary so greatly across primate species, we predicted there would be no sex difference in the relative size of the cerebellum across primates. Results: Our results support our prediction, suggesting there is no consistent sex difference in relative cerebellum size. Conclusion: This work suggests that the potential for sex differences in relative cerebellum size has been subject to either developmental constraint or lack of consistent selection pressures, and highlights the need for more individual-level primate neuroanatomical data to facilitate intra- and inter-specific study of brain sexual dimorphism.

scholarly journals Gene expression correlates of social evolution in coral reef butterflyfishes

2020 ◽  
Vol 287 (1929) ◽  
pp. 20200239 ◽  
Author(s):  
Jessica P. Nowicki ◽  
Morgan S. Pratchett ◽  
Stefan P. W. Walker ◽  
Darren J. Coker ◽  
Lauren A. O'Connell
Keyword(s):  
Gene Expression ◽  
Coral Reef ◽  
Social Evolution ◽  
Brain Regions ◽  
Sexually Dimorphic ◽  
Ventral Telencephalon ◽  
Solitary Living ◽  
Social Variation ◽  
Evolution Of Sociality ◽  
Solitary Species

Animals display remarkable variation in social behaviour. However, outside of rodents, little is known about the neural mechanisms of social variation, and whether they are shared across species and sexes, limiting our understanding of how sociality evolves. Using coral reef butterflyfishes, we examined gene expression correlates of social variation (i.e. pair bonding versus solitary living) within and between species and sexes. In several brain regions, we quantified gene expression of receptors important for social variation in mammals: oxytocin ( OTR ), arginine vasopressin ( V1aR ), dopamine ( D1R, D2R ) and mu-opioid ( MOR ). We found that social variation across individuals of the oval butterflyfish, Chaetodon lunulatus, is linked to differences in OTR , V1aR, D1R, D2R and MOR gene expression within several forebrain regions in a sexually dimorphic manner. However, this contrasted with social variation among six species representing a single evolutionary transition from pair-bonded to solitary living. Here, OTR expression within the supracommissural part of the ventral telencephalon was higher in pair-bonded than solitary species, specifically in males. These results contribute to the emerging idea that nonapeptide, dopamine and opioid signalling is a central theme to the evolution of sociality across individuals, although the precise mechanism may be flexible across sexes and species.

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