Article
Multidisciplinary Sciences
Claudius F. Kratochwil, Andreas F. Kautt, Alexander Nater, Andreas Harer, Yipeng Liang, Frederico Henning, Axel Meyer
Summary: This study uncovers the genetic basis of the gold/dark polymorphism in Midas cichlid fish by identifying a transposon insertion in the gene goldentouch.
NATURE COMMUNICATIONS
(2022)
Article
Ecology
Sabine Urban, Jan Gerwin, C. Darrin Hulsey, Axel Meyer, Claudius F. Kratochwil
Summary: Color patterns are linked to the behavioral and morphological characteristics of animals, and play an important role in antipredatory strategies. This study finds a strong correlation between stripe patterns and body elongation in cichlid fish, indicating that the effectiveness of the stripes as an antipredatory strategy depends on body shape. However, genetic analyses show that stripes and body elongation segregate independently, suggesting that their correlation is maintained by correlational selection rather than genetic linkage. Furthermore, mate preference tests indicate that females do not differentiate between striped and nonstriped males, suggesting that stripes might be less important for species recognition and mate choice.
ECOLOGY AND EVOLUTION
(2022)
Article
Genetics & Heredity
Mark Kirkpatrick, Jason M. Sardell, Brendan J. Pinto, Groves Dixon, Catherine L. Peichel, Manfred Schartl
Summary: This study focuses on the sex chromosomes of the guppy and its close relatives, finding no evidence of a nonrecombining sex-determining region and suggesting that the evolution of sex-determining regions in certain relatives occurred independently. It also addresses conflicting results in previous studies and proposes best practices for future research.
G3-GENES GENOMES GENETICS
(2022)
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
Biochemistry & Molecular Biology
Camila L. Nacif, Claudius F. Kratochwil, Andreas F. Kautt, Alexander Nater, Gonzalo Machado-Schiaffino, Axel Meyer, Frederico Henning
Summary: The evolution and differentiation of sex chromosomes is a significant event in genome evolution, and the repeated evolution and variability of sex-determination mechanisms in fishes make them a suitable model for studying general patterns in evolution. This study used forward-genetics, long-read sequencing, and optical mapping to determine that sex in Midas cichlids is determined by an XY system and identified and assembled the sex-determining region. The study also found that the male-specific region on chromosome 4 contains transposable elements and a Y-specific duplicate of the anti-Mullerian receptor 2 gene, which has evolved as a master sex-determining gene. The duplication of anti-Mullerian genes is a common mechanism for establishing new sex determiners, highlighting the importance of molecular parallelism in the evolution of sex determination.
Article
Biology
Julian Torres-Dowdall, Sina J. Rometsch, Jacobo Reyes Velasco, Gaston Aguilera, Andreas F. Kautt, Guillermo Goyenola, Ana C. Petry, Gabriel C. Depra, Weferson J. da Graca, Axel Meyer
Summary: Phylogenetic comparative studies suggest that the deviation from bilateral symmetry might evolve through genetic assimilation, but the changes in its inheritance are largely unknown. Research on the evolution of genital asymmetry in Anablepidae fish reveals that the bias towards left-sided males has likely evolved independently three times. Breeding experiments show that regardless of their own sidedness, male fish sire more left-sided offspring. This suggests that sidedness may be inherited as a threshold trait with different thresholds across species.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2022)
Article
Ecology
Claudius F. Kratochwil, Andreas F. Kautt, Sina J. Rometsch, Axel Meyer
Summary: High-throughput DNA sequencing technologies have made it easier to sequence entire genomes. Whole-genome resequencing can help identify and describe species that are difficult to discern, but it can be costly and time-consuming. Species-specific markers can be designed based on whole-genome resequencing data, enabling rapid and reliable species identification at a lower cost.
ECOLOGY AND EVOLUTION
(2022)
Article
Cell Biology
Indrajit Nanda, Susanne Schories, Ivan Simeonov, Mateus Contar Adolfi, Kang Du, Claus Steinlein, Manfred Alsheimer, Thomas Haaf, Manfred Schartl
Summary: The conspicuous color sexual dimorphism makes guppies ideal study objects for sex-linked traits and sex chromosome evolution. The Y-chromosome in Micropoecilia. picta has been found to be highly degenerated compared to the X-chromosome, with a low SNP density and high heterochromatin content. This is in contrast to other species in the Poecilia group, indicating that the evolution of sex chromosomes is not parallel.
Article
Evolutionary Biology
Claudius F. Kratochwil, Yipeng Liang, Jan Gerwin, Paolo Franchini, Axel Meyer
Summary: This study investigates the differences between striped and nonstriped cichlid fishes in different lineages of Lake Victoria and Lake Malawi. The gene agrp2 is found to be associated with stripe pattern divergence. The study also examines the development of stripe patterns and vertical bar patterns, and suggests that the stripe phenotype may be caused by a combination of subtle transcriptomic differences or cellular changes.
EVOLUTION & DEVELOPMENT
(2022)
Article
Multidisciplinary Sciences
Heiner Kuhl, Kang Du, Manfred Schartl, Lukas Kalous, Matthias Stoeck, Dunja K. Lamatsch
Summary: Understanding genome evolution of polyploids involves analyzing their similar subgenomes and haplotypes. In this study, the genome of the asexual Prussian carp was sequenced, resulting in a haplotype-resolved chromosome-scale assembly of a hexaploid animal. Comparisons with ancestral diploid cyprinids and goldfish revealed the genome structure, phylogeny, and genome duplication history.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Melisa Olave, Alexander Nater, Andreas F. Kautt, Axel Meyer
Summary: This study presents a rare example of sympatric homoploid hybrid speciation in Midas cichlid fishes from Nicaragua. The hybrid lineage has diverged from its parental species both genomically and phenotypically, and occupies a different trophic niche facilitated by body shape adaptations.
NATURE COMMUNICATIONS
(2022)
Editorial Material
Multidisciplinary Sciences
Manfred Schartl, Dunja K. Lamatsch
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Review
Genetics & Heredity
Manfred Schartl, Arthur Georges, Jennifer A. Marshall Graves
Summary: Genetic sex determination in most vertebrates is controlled by a single master sex gene, but there are also more complex systems, such as polygenic sex determination, where multiple genes interact to determine sex. However, many of the claims for polygenic sex determination in vertebrates are either transient states during sex chromosome turnover or aberrant systems in species hybrids. To avoid confusion, a consistent nomenclature for genetic sex determination systems is proposed.
TRENDS IN GENETICS
(2023)
Article
Evolutionary Biology
Paul Masonick, Axel Meyer, Christopher Darrin Hulsey
Summary: The genomic loci underlying variation in vertebrate structures like lips are surprisingly predictable. Both adaptive and maladaptive variation in traits such as jaws and teeth can be structured by the same genes in evolutionarily disparate organisms like teleost fishes and mammals. The recurrence of hypertrophied lips in cichlid fish lineages suggests the presence of shared genetic bases and potential insights into the genetic factors influencing human craniofacial anomalies.
GENOME BIOLOGY AND EVOLUTION
(2023)
Article
Biochemistry & Molecular Biology
Ralf F. Schneider, Helen M. Gunter, Inken Salewski, Joost M. Woltering, Axel Meyer
Summary: Evolutionary novelties can promote ecological specialization and adaptive radiations. Belonoid fishes, such as flying fishes, halfbeaks, and needlefishes, have highly diversified elongated jaw phenotypes. In this study, the development of elongated jaws in a halfbeak and a needlefish was investigated, revealing that these jaws consist of distinct base and extension portions. The growth dynamics of both bases and extensions were described, and the molecular mechanisms underlying the extension outgrowth were deduced.