Nejvíce citovaný článek - PubMed ID 35306896
Dosage compensation evolution in plants: theories, controversies and mechanisms
Chromosomal sex-determining systems with male heterogamety include actively male-determining-Y and X-A balance systems, both of which are found in animals and plants. The sex-determining genes have been identified in several active-Y plant systems, but the evolution and functioning of X-A balance systems remains mysterious. Here we sequenced and compared the genomes of two hop species. The evolution of the hop X-A balance system involved an ancient recombination suppression event across a large X chromosome region shared by both species. In one species, an autosome fused to this ancestral sex chromosome, and recombination was subsequently suppressed again. The two evolutionary strata created in this neo-X have degenerated to different degrees and evolved correspondingly different dosage compensation levels that correlate with histone modification patterns. Finally, we identified an X-specific ETR1-like ethylene receptor in the ancestral X region. Its dosage may affect sex determination, as part of the counting mechanism of this X-A balance system.
Sex chromosomes have evolved in many plant species with separate sexes. Current plant research is shifting from examining the structure of sex chromosomes to exploring their functional aspects. New studies are progressively unveiling the specific genetic and epigenetic mechanisms responsible for shaping distinct sexes in plants. While the fundamental methods of molecular biology and genomics are generally employed for the analysis of sex chromosomes, it is often necessary to modify classical procedures not only to simplify and expedite analyses but sometimes to make them possible at all. In this review, we demonstrate how, at the level of structural and functional genetics, cytogenetics, and bioinformatics, it is essential to adapt established procedures for sex chromosome analysis.
- Klíčová slova
- Bioinformatics, chromosome dissection, cytogenetics, dioecious plants, epigenetics, functional genetics, sex chromosomes, tandem repeats, transposable elements,
- MeSH
- chromozomy rostlin * genetika MeSH
- pohlavní chromozomy * genetika MeSH
- rostliny genetika MeSH
- výpočetní biologie metody MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC), known as oxi-mCs, garners significant interest in plants as potential epigenetic marks. While research in mammals has established a role in cell reprogramming, carcinogenesis, and gene regulation, their functions in plants remain unclear. In rice, 5hmC has been associated with transposable elements (TEs) and heterochromatin. This study utilizes Silene latifolia, a dioecious plant with heteromorphic sex chromosomes and a genome with a large proportion of TEs, which provides a favourable environment for the study of oxi-mCs in individual sexes. Notably, we detected surprisingly high levels of oxi-mCs in S. latifolia comparable with mammals. Nuclei showed enrichment in heterochromatic regions, except for 5hmC whose signal was homogeneously distributed. Intriguingly, the same X chromosome in females displayed overall enrichment of 5hmC and 5fC compared with its counterpart. This fact is shared with 5mC, resembling dosage compensation. Co-localization showed higher correlation between 5mC and 5fC than with 5hmC, indicating no potential relationship between 5hmC and 5fC. Additionally, the promoter of several sex-linked genes and sex-biased TEs clustered in a clear sex-dependent way. Together, these findings unveil a hypothetical role for oxi-mCs in S. latifolia sex chromosome development, warranting further exploration.
- Klíčová slova
- Silene latifolia, Cytosine modifications, dosage compensation, oxi-mCs, sex chromosomes, transposable elements,
- MeSH
- 5-methylcytosin metabolismus analogy a deriváty MeSH
- chromozomy rostlin * genetika MeSH
- epigeneze genetická MeSH
- pohlavní chromozomy * genetika MeSH
- Silene * genetika MeSH
- transpozibilní elementy DNA genetika MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- 5-methylcytosin MeSH
- transpozibilní elementy DNA MeSH
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel's anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel's early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
- Klíčová slova
- FISH, NGS, TRAP, eukaryotic tree of life, interstitial telomere sequences, retroelements, satellite, subtelomere structure, telomerase RNA, telomere evolution,
- MeSH
- DNA MeSH
- lidé MeSH
- repetitivní sekvence nukleových kyselin MeSH
- satelitní DNA * MeSH
- sekvence nukleotidů MeSH
- telomery * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- DNA MeSH
- satelitní DNA * MeSH
