scholarly journals Maintenance of polygenic sex determination in a fluctuating environment: an individual-based model

2017 ◽  
Vol 30 (5) ◽  
pp. 915-925 ◽  
Author(s):  
A. W. Bateman ◽  
B. R. Anholt
Keyword(s):  
Sex Determination ◽  
Individual Based Model ◽  
Fluctuating Environment ◽  
Polygenic Sex Determination

scholarly journals The maintenance of polygenic sex determination depends on the dominance of fitness effects which are predictive of the role of sexual antagonism

2021 ◽  
Author(s):  
Richard P Meisel
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
House Fly ◽  
Sexual Antagonism ◽  
Antagonistic Effects ◽  
Fitness Effects ◽  
Y Chromosomes ◽  
Sexually Antagonistic Selection ◽  
The Individual ◽  
Polygenic Sex Determination

Abstract In species with polygenic sex determination, multiple male- and female-determining loci on different proto-sex chromosomes segregate as polymorphisms within populations. The extent to which these polymorphisms are at stable equilibria is not yet resolved. Previous work demonstrated that polygenic sex determination is most likely to be maintained as a stable polymorphism when the proto-sex chromosomes have opposite (sexually antagonistic) fitness effects in males and females. However, these models usually consider polygenic sex determination systems with only two proto-sex chromosomes, or they do not broadly consider the dominance of the alleles under selection. To address these shortcomings, I used forward population genetic simulations to identify selection pressures that can maintain polygenic sex determination under different dominance scenarios in a system with more than two proto-sex chromosomes (modeled after the house fly). I found that overdominant fitness effects of male-determining proto-Y chromosomes are more likely to maintain polygenic sex determination than dominant, recessive, or additive fitness effects. The overdominant fitness effects that maintain polygenic sex determination tend to have proto-Y chromosomes with sexually antagonistic effects (male-beneficial and female-detrimental). In contrast, dominant fitness effects that maintain polygenic sex determination tend to have sexually antagonistic multi-chromosomal genotypes, but the individual proto-sex chromosomes do not have sexually antagonistic effects. These results demonstrate that sexual antagonism can be an emergent property of the multi-chromosome genotype without individual sexually antagonistic chromosomes. My results further illustrate how the dominance of fitness effects has consequences for both the likelihood that polygenic sex determination will be maintained as well as the role sexually antagonistic selection is expected to play in maintaining the polymorphism.

MODELS OF POLYGENIC SEX DETERMINATION AND SEX RATIO CONTROL

Evolution ◽  
1982 ◽  
Vol 36 (1) ◽  
pp. 13-26 ◽  
Author(s):  
M. G. Bulmer ◽  
J. J. Bull
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Polygenic Sex Determination

scholarly journals Polygenic sex determination

2013 ◽  
Vol 23 (12) ◽  
pp. R510-R512 ◽  
Author(s):  
Emily C. Moore ◽  
Reade B. Roberts
Keyword(s):  
Sex Determination ◽  
Polygenic Sex Determination

scholarly journals Temperature-dependent effects of house fly proto-Y chromosomes on gene expression act independently of the sex determination pathway

2020 ◽  
Author(s):  
Kiran Adhikari ◽  
Jae Hak Son ◽  
Anna H. Rensink ◽  
Jaweria Jaweria ◽  
Daniel Bopp ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Sex Chromosomes ◽  
Developmental Process ◽  
Natural Populations ◽  
House Fly ◽  
Sexually Dimorphic ◽  
Temperature Dependent ◽  
Y Chromosomes ◽  
Polygenic Sex Determination

AbstractSex determination, the developmental process by which sexually dimorphic phenotypes are established, evolves fast. Species with polygenic sex determination, in which master regulatory genes are found on multiple different proto-sex chromosomes, are informative models to study the evolution of sex determination. House flies are such a model system, with male determining loci possible on all six chromosomes and a female-determiner on one of the chromosomes as well. The distributions of the two most common male-determining proto-Y chromosomes across natural populations suggests that temperature variation is an important selection pressure responsible for maintaining polygenic sex determination in this species. To test that hypothesis, we used RNA-seq to identify temperature-dependent effects of the proto-Y chromosomes on gene expression. We find no evidence for ecologically meaningful temperature-dependent expression of sex determining genes between male genotypes, but we identified hundreds of other genes whose expression depends on the interaction between proto-Y chromosome genotype and temperature. Notably, genes with genotype-by-temperature interactions on expression are not enriched on the proto-sex chromosomes. Moreover, there is no evidence that temperature-dependent expression is driven by chromosome-wide expression divergence between the proto-Y and proto-X alleles. Therefore, if temperature-dependent gene expression is responsible for differences in phenotypes and fitness of proto-Y genotypes across house fly populations, these effects are driven by a small number of temperature-dependent alleles on the proto-Y chromosomes.

scholarly journals The maintenance of polygenic sex determination depends on the dominance of fitness effects which are predictive of the role of sexual antagonism

2020 ◽  
Author(s):  
Richard P. Meisel
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Natural Populations ◽  
House Fly ◽  
Sexual Antagonism ◽  
Antagonistic Selection ◽  
Fitness Effects ◽  
Y Chromosomes ◽  
Sexually Antagonistic Selection ◽  
Polygenic Sex Determination

AbstractIn species with polygenic sex determination, multiple male- and/or female-determining loci on different proto-sex chromosomes segregate as polymorphisms within populations. The extent to which these polymorphisms are stable equilibria is not yet resolved. Previous work demonstrated that polygenic sex determination is most likely to be maintained as a stable polymorphism when the proto-sex chromosomes have opposite (sexually antagonistic) fitness effects in males and females. However, these models usually consider polygenic sex determination systems with only two proto-sex chromosomes, or they do not broadly consider the dominance of the variants under selection. To address these shortcomings, I used forward population genetic simulations to identify selection pressures that can maintain polygenic sex determination under different dominance scenarios in a system with more than two proto-sex chromosomes (modeled after the house fly). I found that overdominant fitness effects of male-determining proto-Y chromosomes in males are more likely to maintain polygenic sex determination than dominant, recessive, or additive fitness effects. I also found that additive fitness effects that maintain polygenic sex determination have the strongest signatures of sexually antagonistic selection, but there is also some evidence for sexually antagonism when fitness effects of proto-Y chromosomes are dominant or recessive. More generally, these results suggest that the expected effect of sexually antagonistic selection on the maintenance of genetic variation in natural populations will depend on whether the alleles are sex-linked and the dominance of their fitness effects.

Models of Polygenic Sex Determination and Sex Ratio Control

Evolution ◽  
1982 ◽  
Vol 36 (1) ◽  
pp. 13 ◽  
Author(s):  
M. G. Bulmer ◽  
J. J. Bull
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Polygenic Sex Determination

scholarly journals Polygenic Sex Determination System in Zebrafish

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e34397 ◽  
Author(s):  
Woei Chang Liew ◽  
Richard Bartfai ◽  
Zijie Lim ◽  
Rajini Sreenivasan ◽  
Kellee R. Siegfried ◽  
...  
Keyword(s):  
Sex Determination ◽  
Determination System ◽  
Sex Determination System ◽  
Polygenic Sex Determination

scholarly journals Unraveling the genotype by environment interaction in a thermosensitive fish with a polygenic sex determination system

2021 ◽  
Vol 118 (50) ◽  
pp. e2112660118
Author(s):  
Benjamin Geffroy ◽  
Mathieu Besson ◽  
Núria Sánchez-Baizán ◽  
Frederic Clota ◽  
Alexander Goikoetxea ◽  
...  
Keyword(s):  
Sex Determination ◽  
Threshold Model ◽  
Energy Levels ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Environment Interaction ◽  
European Sea Bass ◽  
Determination System ◽  
Sex Determination System ◽  
Polygenic Sex Determination

In most animals, sex determination occurs at conception, when sex chromosomes are segregated following Mendelian laws. However, in multiple reptiles and fishes, this genetic sex can be overridden by external factors after fertilization or birth. In some species, the genetic sex may also be governed by multiple genes, further limiting our understanding of sex determination in such species. We used the European sea bass (Dicentrarchus labrax) as a model and combined genomic (using a single nucleotide polymorphism chip) and transcriptomic (RNA-Sequencing) approaches to thoroughly depict this polygenic sex determination system and its interaction with temperature. We estimated genetic sex tendency (eGST), defined as the estimated genetic liability to become a given sex under a liability threshold model for sex determination, which accurately predicts the future phenotypic sex. We found evidence that energetic pathways, concerning the regulation of lipids and glucose, are involved in sex determination and could explain why females tend to exhibit higher energy levels and improved growth compared to males. Besides, early exposure to high-temperature up-regulated sox3, followed by sox9a in individuals with intermediate eGST, but not in individuals showing highly female-biased eGST, providing the most parsimonious explanation for temperature-induced masculinization. This gonadal state was maintained likely by DNA methylation and the up-regulation of several genes involved in histone modifications, including jmjd1c. Overall, we describe a sex determination system resulting from continuous genetic and environmental influences in an animal. Our results provide significant progress in our understanding of the mechanisms underlying temperature-induced masculinization in fish.

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