Article
Multidisciplinary Sciences
Emily C. Moore, Patrick J. Ciccotto, Erin N. Peterson, Melissa S. Lamm, R. Craig Albertson, Reade B. Roberts
Summary: For many vertebrates, a single genetic locus initiates a cascade of developmental sex differences, resulting in adults with two phenotypically distinct sexes. However, species with polygenic sex determination have multiple interacting sex determination alleles, allowing for more than two genotypic sexes. In the cichlid fish Metriaclima mbenjii, polygenic sex determination produces modular variation in morphological and behavioral traits, and the evolution or introgression of a newly acquired sex determiner creates additional axes of phenotypic variation.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Gregoire Vernaz, Milan Malinsky, Hannes Svardal, Mingliu Du, Alexandra M. Tyers, M. Emilia Santos, Richard Durbin, Martin J. Genner, George F. Turner, Eric A. Miska
Summary: Lake Malawi cichlid fishes exhibit extensive phenotypic diversity despite low sequence divergence. The study reveals substantial methylome divergence among closely-related cichlid fishes, with differentially methylated regions associated with transcription changes of ecologically-relevant genes. This research provides insights into the role of epigenetics in species diversification.
NATURE COMMUNICATIONS
(2021)
Article
Genetics & Heredity
Nicolas Lichilin, Walter Salzburger, Astrid Boehne
Summary: Research shows that the sex determination system can vary between populations of the same fish species. A study on Astatotilapia burtoni, a fish species found in Lake Tanganyika, revealed that there are different sex determination systems in natural populations compared to laboratory strains. The analysis of the species' genomes did not detect differentiated sex chromosomes, suggesting that the sex determination system in A. burtoni is more flexible and may involve non-genetic or poorly differentiated sex chromosomes.
G3-GENES GENOMES GENETICS
(2023)
Article
Genetics & Heredity
Thomas D. Kocher, Kristen A. Behrens, Matthew A. Conte, Mitsuto Aibara, Hillary D. J. Mrosso, Elizabeth C. J. Green, Michael R. Kidd, Masato Nikaido, Stephan Koblmuller
Summary: African cichlid fishes exhibit a diverse range of sex-chromosome systems, with at least 13 distinct systems identified in the haplochromine lineage. This study focuses on characterizing sex chromosomes in cichlids from the Lake Victoria basin and identifies several new systems as well as highlighting the dynamic evolution of sex determination and sex chromosomes in this lineage.
Article
Evolutionary Biology
Paul Masonick, Axel Meyer, Christopher Darrin Hulsey
Summary: By analyzing the genomes of Lake Malawi cichlid species, this study found that protein-coding single nucleotide polymorphisms (SNPs) can provide enough phylogenetic information to study the inter- and intra-specific relationships of hypertrophied lip cichlids, although noncoding SNPs provide better support. The study also revealed that hypertrophied lip cichlids have likely evolved independently at least twice in Lake Malawi.
GENOME BIOLOGY AND EVOLUTION
(2022)
Article
Marine & Freshwater Biology
C. Darrin Hulsey, Courtney E. Gorman
Summary: This study examined the relationship between the length of the premaxillary ascending process and jaw protrusion in Malawi cichlid species. The research found a significant correlation between the ascending process length and maximum jaw protrusion distance, but no association with protrusion angle. These findings provide insights into the evolutionary mechanisms contributing to cichlid fish diversity.
Article
Plant Sciences
Aretuza Sousa, Veit Schubert, Susanne S. Renner
Summary: The study identified different types of sex chromosomes in liverworts, investigated their recombination environments using molecular cytogenetics and super-resolution microscopy, and found that the heteromorphic sex chromosomes in Frullania dilatata are distinct from autosomes and each other. The similarity between the U chromosomes suggests they may have originated from a non-disjunction event.
Article
Biochemistry & Molecular Biology
Jason M. Sardell, Matthew P. Josephson, Anne C. Dalziel, Catherine L. Peichel, Mark Kirkpatrick
Summary: By comparing closely related species with homologous sex chromosomes, researchers have found that the sex chromosomes of the blackspotted stickleback experienced independent and more extensive recombination suppression, greater X-Y differentiation, and a much higher rate of Y degeneration than the other two species. This could be due to the smaller effective population size in the blackspotted stickleback. Additionally, a recent fusion between the ancestral blackspotted stickleback Y chromosome and Chromosome 12 may have been favored by the very small size of the recombining region on the ancestral sex chromosome.
MOLECULAR BIOLOGY AND EVOLUTION
(2021)
Article
Biology
Mariannah Pravatti Barcellos de Oliveira, Rafael Kretschmer, Geize Aparecida Deon, Gustavo Akira Toma, Tariq Ezaz, Caio Augusto Gomes Goes, Fabio Porto-Foresti, Thomas Liehr, Ricardo Utsunomia, Marcelo de Bello Cioffi
Summary: In this study, the dynamics of satellite DNAs (SatDNAs) accumulation and elimination during W chromosome differentiation in Triportheus fish were investigated. The majority of repetitive sequences were eliminated as speciation occurred in five additional Triportheus species. While the W chromosomes continued to degenerate, the Z chromosomes in some species began to accumulate TauSatDNAs. Species-specific SatDNAs were likely amplified in the heterochromatic regions of both Z and W chromosomes in each species. Thus, the W chromosomes of various Triportheus species underwent significant evolutionary changes within a short period of time (15-25 Myr) after divergence.
Article
Biology
Evan Lloyd, Brian Chhouk, Andrew J. Conith, Alex C. Keene, R. Craig Albertson
Summary: Animals exhibit diverse patterns of rest and activity, influenced by foraging strategies, social behaviors, and predator avoidance. The cichlid species in Lake Malawi provide a unique opportunity to study variation in locomotor behavior, with surprising variability in circadian timing and rest duration. Nocturnal behavior in some species is associated with increased eye size and may be a response to light rather than an internal circadian rhythm.
JOURNAL OF EXPERIMENTAL BIOLOGY
(2021)
Article
Cell Biology
Barbora Augstenova, Eleonora Pensabene, Lukas Kratochvil, Michail Rovatsos
Summary: Anguimorphan lizards are a group of squamate reptiles with wide geographical distribution and morphological variability. Their karyotypes show significant variation across different lineages, with Anguids exhibiting the most variability. The study documented differentiated sex chromosomes in monitors and helodermatids, as well as in some anguids, and also revealed a rare case of spontaneous triploidy in Varanus primordius.
Article
Ecology
Dina Navon, Paul Hatini, Lily Zogbaum, R. Craig Albertson
Summary: The research found that plasticity is generally integrated across a range of ecologically relevant traits, with traits that have overlapping functions responding in a coordinated manner. Genetic data suggest a compromise between global genetic regulators and integration across traits for plasticity.
Article
Biochemistry & Molecular Biology
Virginie Ricci, Fabrizia Ronco, Zuzana Musilova, Walter Salzburger
Summary: This study examined the diversity and sequence evolution of RH1 in the adaptive radiation of cichlid fishes in Lake Tanganyika, focusing on adaptations to the environmental light with respect to depth. The findings show that Tanganyikan cichlid genomes contain a single copy of RH1 and have several variable sites that may be functionally important in terms of depth-related adaptations. The study provides new insights into the evolution of RH1 in a freshwater environment.
Article
Multidisciplinary Sciences
Kristen A. Behrens, Stephan Koblmuller, Thomas D. Kocher
Summary: This study reveals a high rate of sex chromosome turnover in East African cichlid fishes, with sex determining loci described on at least 12 of 22 chromosomes. New sex chromosome loci were identified and the differentiation of chromosomes appears to have occurred in a single step in certain cases.
SCIENTIFIC REPORTS
(2022)
Article
Marine & Freshwater Biology
Chahrazed Rahmouni, Maarten Van Steenberge, Maarten P. M. Vanhove, Andrea Simkova
Summary: The research indicates that parasite populations parasitizing hosts with poor dispersal capacity are more differentiated compared to populations parasitizing hosts with good dispersal capacity, showing more shape variation among individuals.
