Evolutionary history of recombination on newly evolved sex chromosomes
Lead Research Organisation:
University College London
Department Name: Structural Molecular Biology
Abstract
Strategic Research Priority: World Class Bioscience
Sex chromosomes have evolved countless times in numerous animal and plant species and represent an important example of evolutionary convergence. Despite the prevalence and importance of sex chromosomes, we understand little about their early evolution, largely because our knowledge is limited to systems with ancient and highly derived sex chromosomes. This project will address the early stages of sex chromosome evolution in an emerging model system, the guppy, to answer questions about how and why sex chromosomes emerge, under what conditions they are maintained, and how they diverge.
Project
Sex chromosomes originate from autosomes, and form when recombination is halted between the emerging X and Y chromosomes. Halting recombination between them allows the nascent X and Y chromosomes to diverge from each other, leading to differences in size, coding content and repeat elements. The evolutionary consequences of recombination suppression between the sex chromosomes, including loss of gene function on the Y, sexualisation of gene expression of the X, as well as a host of others, have occurred repeatedly and independently in scores of lineages, and sex chromosomes therefore represent a case of massive evolutionary convergence. Moreover, the crucial connection between sex chromosome divergence and recombination makes sex chromosomes a compelling model for the study of the interplay between selection, adaptation and recombination.
This project is designed to study the early stages of recombination suppression in order to identify the mechanism by which sex chromosomes diverge. The project will utilize evolutionary genomic analysis using existing genome assemblies, as well as DNA-Seq and RNA-Seq data generated specifically for this project. The student will learn a range of bioinformatics and wet-lab genetic techniques for the analysis of genomes, and will work closely with the supervisor and other members of the research group.
Sex chromosomes have evolved countless times in numerous animal and plant species and represent an important example of evolutionary convergence. Despite the prevalence and importance of sex chromosomes, we understand little about their early evolution, largely because our knowledge is limited to systems with ancient and highly derived sex chromosomes. This project will address the early stages of sex chromosome evolution in an emerging model system, the guppy, to answer questions about how and why sex chromosomes emerge, under what conditions they are maintained, and how they diverge.
Project
Sex chromosomes originate from autosomes, and form when recombination is halted between the emerging X and Y chromosomes. Halting recombination between them allows the nascent X and Y chromosomes to diverge from each other, leading to differences in size, coding content and repeat elements. The evolutionary consequences of recombination suppression between the sex chromosomes, including loss of gene function on the Y, sexualisation of gene expression of the X, as well as a host of others, have occurred repeatedly and independently in scores of lineages, and sex chromosomes therefore represent a case of massive evolutionary convergence. Moreover, the crucial connection between sex chromosome divergence and recombination makes sex chromosomes a compelling model for the study of the interplay between selection, adaptation and recombination.
This project is designed to study the early stages of recombination suppression in order to identify the mechanism by which sex chromosomes diverge. The project will utilize evolutionary genomic analysis using existing genome assemblies, as well as DNA-Seq and RNA-Seq data generated specifically for this project. The student will learn a range of bioinformatics and wet-lab genetic techniques for the analysis of genomes, and will work closely with the supervisor and other members of the research group.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M009513/1 | 01/10/2015 | 31/03/2024 | |||
| 1622040 | Studentship | BB/M009513/1 | 01/10/2015 | 30/09/2019 | Iulia Darolti |
| Description | Despite sharing the majority of their genome, males and females of the same species often show a wealth of phenotypic differences, affecting morphology, physiology, behavior and life history, among other traits. Through my research, I investigate how sex-specific evolutionary pressures shape distinct male and female phenotypes. In some species, the two sexes differ by their sex chromosomes, which partly explains the observed sexual differences. To a large extent, however, sex differences are encoded by genes that are shared between males and females but that are expressed differently in the two sexes (referred to as sex-biased genes). In my research, I integrate genomic and transcriptomic data to explore the evolution of sex chromosomes and of sex-biased gene expression and their role in differences between the sexes. While there is a wealth of studies on the evolutionary dynamics of sex-biased genes in animals, little is known about the molecular evolution of sex-biased genes in plants in general, and in flowering plants in particular. Animals and plants can be subject to different selection pressures and through my work, I have shown the importance of comparative studies between animals and plant systems with regards to the evolution of sex-biased genes and their effects on sex differences. While in some taxa sex chromosomes are preserved across many species, in others, such as fish, sex chromosome systems can differ even between closely related species or populations of the same species. My work on the evolution of sex chromosomes reveals an extreme variation in sex chromosome morphology across related livebearing fish with implications for differences between males and females. |
| Exploitation Route | Differences between males and females could have an impact on the outcomes of many biomedical research studies. A better understanding of the genetics of many traits and studying both males and females is extremely important for many research fields, especially for medical research. |
| Sectors | Agriculture, Food and Drink,Education,Healthcare,Pharmaceuticals and Medical Biotechnology |
| Description | Soapbox Science London |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | I was a speaker at the London Soapbox Science event in 2018, where I shared my PhD work and engaged in scientific discussions with members of the general public. This event has brought science to the streets and challenged the public's view of women in science. |
| Year(s) Of Engagement Activity | 2018 |