Biology subjects

Romanenko, S.

Publications and source records attributed to Romanenko, S..

4 recordsLinked to original sources

bioRxiv2023

Genomic Underground: Unraveling NUMTs in Mole Voles

Nuclear mitochondrial DNA segments (NUMTs) are pervasive elements of eukaryotic genomes. This study focuses on Ellobius talpinus and Ellobius lutescens, for which we assembled full mitochondrial DNA sequences. Our study identified NUMTs encompassing approximately 0.0052% and 0.0086% of genome assembly length in E. talpinus and E. lutescens, respectively. These NUMTs collectively spanned a total length of 122,294 bp in E. talpinus and 194,875 bp in E. lutescens. Notably, the majority of NUMTs in both species were short, with lengths of less than 500 bp. In E. talpinus, the data indicated the presence of comparatively recent NUMT insertions. More than half of the NUMTs in each species are organized into clusters, primarily situated in intergenic regions or within introns. RNA genes are the most frequently occurring fragments within these NUMTs. Furthermore, our analysis identified LINE, SINE, and LTR retrotransposons within and flanking NUMT clusters. Our results demonstrate the intricate dynamics of NUMT integration and distribution in Ellobius species and provide insights into their genomic architecture and evolutionary history. This study contributes to the broader understanding of mitochondrial DNA contributions to nuclear genomes and underscores the complexity of distinguishing between mtDNA and nuclear DNA in genomic studies.

genomics↗

bioRxiv2020

Whole-chromosome fusions in the karyotype evolution of Sceloporus (Iguania, Reptilia) are more intense in sex chromosomes than autosomes

There is a growing body of evidence that the common ancestor of vertebrates had a bimodal karyotype, i.e. consisting of large macrochromosomes and small microchromosomes. This type of karyotype organization is preserved in most reptiles. However, certain species independently experience microchromosome fusions. The evolutionary forces behind this are unclear. We investigated the karyotype of the green spiny lizard, Sceloporus malachiticus, an iguana species which has 2n=22, whereas the ancestral karyotype of iguanas had 2n=36. We obtained and sequenced flow-sorted chromosome-specific DNA samples and found that most of the microchromosome fusions in this species involved sex chromosomes. We found that certain ancestral squamate chromosomes, such as the homologue of the Anolis carolinensis chromosome 11, are repeatedly involved in sex chromosome formation in different species. To test the hypothesis that the karyotypic shift could be associated with changes in recombination patterns, and to study sex chromosome synapsis and recombination in meiosis, we performed synaptonemal complex analysis in this species and in S. variabilis, a related species with 2n=34. We found that in the species studied the recombination patterns correlate more with phylogeny than with the structure of the karyotype. The sex chromosomes had two distal pseudoautosomal regions and a medial differentiated region.

genomics↗

bioRxiv2019

Chromosome painting does not support a sex chromosome turnover in Lacerta agilis Linnaeus, 1758

Reptiles show a remarkable diversity of sex determination mechanisms and sex chromosome systems, derived from different autosomal pairs. The origin of the ZW sex chromosomes of Lacerta agilis, a widespread Eurasian lizard species, is a matter of discussion: is it a small macrochromosome from the 11-18 group, common to all lacertids, or this species has unique ZW pair derived from the large chromosome 5. Using independent molecular cytogenetic methods, we investigated the karyotype of L. agilis exigua from Siberia, Russia, to identify the sex chromosomes. FISH with the flow-sorted chromosome painting probe, derived from L. strigata and specific to chromosomes 13, 14, and Z, confirmed that the Z chromosome of L. agilis is a small macrochromosome, the same as in L. strigata. FISH with the telomeric probe showed an extensive accumulation of the telomeric repeat on the W chromosome in agreement with previous studies, excluding the possibility that the lineages of L. agilis studied in different works could have different sex chromosome systems due to a putative intra-species polymorphism. Our results reinforce the idea of the stability of the sex chromosomes and lack of evidence for sex-chromosome turnovers in known species of Lacertidae.

evolutionary biology↗

bioRxiv2018

Millimetre wave radiation activates leech nociceptors via TRPV1-like receptor sensitisation

Due to new applications such as wireless communications, security scanning, and imaging the presence of artificially generated high frequency (30-300 GHz) millimetre-wave (MMW) signals in the environment is increasing. Although safe exposure levels have been set by studies involving direct thermal damage to tissue, there is evidence that MMWs can have an impact on cellular function, including neurons. Earlier in vitro studies have shown that exposure levels well below the recommended safe limit of 1mW/cm2 cause changes in the action potential (AP) firing rate, resting potential, and AP pulse shape of sensory neurons in leech preparations, as well as alter neuronal properties in rat cortical brain slices; these effects differ from changes induced by direct heating. In this paper we examine continuous MMW power (up to 80 mW/cm2 at 60 GHz) and evaluate the responses in the thermosensitive primary nociceptors of the medicinal leech (genus Richardsonianus Australis). The results show that MMW exposure causes an almost two-fold decrease in the threshold for activation of the AP compared with conductive heating (3.6{+/-}0.4 mV vs. 6.5{+/-}0.4 mV respectively). Our analysis suggests that MMW exposure mediated threshold alterations are not caused by enhancement of voltage gated sodium and potassium conductance. Moreover, it appears that MMW exposure has a modest suppressing effect on membrane excitability. We propose that the reduction in AP threshold can be attributed to sensitization of the TRPV1-like receptor in the leech nociceptor. In silico modelling supported the experimental findings. Our results provide evidence that MMW exposure stimulates specific receptor responses that differ from direct conductive heating, fostering the need for additional studies.

biophysics↗