Biology subjects

Sumbera, R.

Publications and source records attributed to Sumbera, R..

3 recordsLinked to original sources

bioRxiv2026

When longevity becomes chemistry: Why rodent brains lack neuromelanin

Background: The biology of neuromelanin (NMel) is linked to Parkinson's disease, in which pigment accumulation and release contribute to dopaminergic cell loss. Rodent brains lack detectable levels of NMel, despite possessing the molecular machinery required for its synthesis. The basis for this absence remains unknown. Objectives: To determine whether long-living rodents accumulate NMel and to test whether lifespan constraints explain the lack of pigmentation in mice and rats. Methods: Histological stains were conducted in brain samples of mole rats of different ages to disclose the potential pigmentation of catecholaminergic centers and to determine the chemical phenotype of pigmented neurons. Results: Mole rats exhibited clear age-dependent NMel accumulation beginning after two years of age, with the highest pigmentation levels observed in neurons of the locus coeruleus. Conclusions: Accumulation of NMel is a slow kinetic process that requires extended longevity. Common laboratory rodents lack pigmented brains simply because they do not live long enough to reach detectable NMel levels.

neuroscience↗

bioRxiv2023

Topographic barriers drive the pronounced genetic subdivision of a range-limited fossorial rodent

Due to their limited dispersal ability, fossorial species with predominantly belowground activity usually show increased levels of population subdivision across relatively small spatial scales. This may be exacerbated in harsh mountain ecosystems, where landscape geomorphology limits species dispersal ability and leads to small effective population sizes, making species susceptible to environmental change. The giant root-rat (Tachyoryctes macrocephalus) is a highly fossorial rodent confined to the afro-alpine ecosystem of the Bale Mountains in Ethiopia. Using mitochondrial and low-coverage nuclear genomes, we investigated 77 giant root-rat individuals sampled from nine localities across its whole [~]1,000 km2 range. Our data revealed a distinct division into a northern and southern subpopulation, with no signs of gene flow, and higher nuclear genetic diversity in the south. Landscape genetic analyses of the mitochondrial genomes indicated that population subdivision was driven by steep slopes and elevation differences of up to 500 m across escarpments separating the north and south, potentially reinforced by glaciation of the south during the Late Pleistocene ([~]42,000 to 16,000 years ago). Despite the pronounced subdivision observed at the range-wide scale, weak geographic structuring of sampling localities within subpopulations indicated gene flow across distances of at least 16 km, suggesting aboveground dispersal and high mobility for relatively long distances. Our study highlights how topographic barriers can lead to the genetic subdivision of fossorial species, despite their potential to maintain gene flow at the local scale. These factors can reduce genetic variability, which should be considered when developing conservation strategies.

evolutionary biology↗

bioRxiv2017

Mashona Mole-Rat Automatic Individual Identification Based on the Mating Calls

In this study was tested mole-rat vocalization for presence of diverse individually distinctive features. An automatic system based on the GMM-UBM was used for individual recognition. The system distinguishes the recordings of the five mole-rats females. The overall achieved identification accuracy is 76.7%, the lowest 59.2%, and the highest 83.5%. The overall percentage is thus high enough to prove that the mating calls of the Mashona mole-rat can carry information about mole-rat individuality. Our results showed that studied vocal signals in the Mashona mole-rats are individually specific which indicates the possibility of individual vocal recognition in this species.

animal behavior and cognition↗