Lampbrush chromosomes of Danio rerio.

Danio rerio, commonly known as zebrafish, is an established model organism for the developmental and cell biology studies. Although significant progress has been made in the analysis of the D. rerio genome, cytogenetic studies face challenges due to the unclear identification of chromosomes.

The first chicken oocyte nucleus whole transcriptomic profile defines the spectrum of maternal mRNA and non-coding RNA genes transcribed by the lampbrush chromosomes.

Lampbrush chromosomes, with their unusually high rate of nascent RNA synthesis, provide a valuable model for studying mechanisms of global transcriptome up-regulation. Here, we obtained a whole-genomic profile of transcription along the entire length of all lampbrush chromosomes in the chicken karyotype. With nuclear RNA-seq, we obtained information about a wider set of transcripts, including long non-coding RNAs retained in the nucleus and stable intronic sequence RNAs.

Karyotypes of water frogs from the Pelophylax esculentus complex: results of cross-species chromosomal painting.

Amphibian species have the largest genome size enriched with repetitive sequences and relatively similar karyotypes. Moreover, many amphibian species frequently hybridize causing nuclear and mitochondrial genome introgressions. In addition, hybridization in some amphibian species may lead to clonality and polyploidization.

Assignment of the somatic A/B compartments to chromatin domains in giant transcriptionally active lampbrush chromosomes.

Background: The three-dimensional configuration of the eukaryotic genome is an emerging area of research. Chromosome conformation capture outlined genome segregation into large scale A and B compartments corresponding mainly to transcriptionally active and repressive chromatin. It remains unknown how the compartmentalization of the genome changes in growing oocytes of animals with hypertranscriptional type of oogenesis.

Lampbrush chromosome studies in the post-genomic era.

Extraordinary extended lampbrush chromosomes with thousands of transcription loops are favorable objects in chromosome biology. Chromosomes become lampbrushy due to unusually high rate of transcription during oogenesis. However, until recently, the information on the spectrum of transcribed sequences as well as genomic context of individual chromomeres was mainly limited to tandemly repetitive elements.