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Comparative chromosome and mitochondrial DNA analyses and phylogenetic relationships within common voles (Microtus,
N A Mazurok1, N V Rubtsova, A A Isaenko
1Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Department, Novosibirsk.
Abstract:
The four species of common voles within the genus Microtus--M. kirgisorum, M. transcaspicus, M. arvalis, and M. rossiaemeridionalis--are so closely related that neither morphological features nor paleontological evidence allow clarification of their phylogeny. Analysis of vole karyotypes and mitochondrial DNA sequences, therefore, is essential for determining their phylogenetic relationships. A comparison of high resolution GTG-banding patterns allows us to ascertain the similarity between the karyotypes of these species, revealing that they are composed of rearrangements of the same chromosomal elements. Based on this analysis, we propose possible routes of chromosomal divergence involved in speciation within this group of voles and construct a phylogenetic tree of their karyotypes. We suggest that two different karyotypic variants existed during the course of vole evolution--one resulting in M. rossiaemeridionalis and M. transcaspicus, the other, M. kirgisorum and M. arvalis. As an alternative approach FITCH and KITSCH computer programs were used to construct a phylogenetic tree of vole molecular evolution based on a pairwise comparison of mitochondrial cytochrome b sequences and the divergence time of the species was determined. The correlation between the trees constructed using karyologic and molecular approaches is discussed in the context of other available data.
Insights
Phylogenetic analysis of common voles using karyotype and mitochondrial DNA reveals distinct evolutionary paths. This research clarifies the speciation of closely related Microtus species.
Area of Science:
- Zoology
- Genetics
- Evolutionary Biology
Background:
- The phylogeny of four closely related common vole species (genus Microtus) remains unclear due to limited morphological and paleontological data.
- Karyotypic and molecular analyses are crucial for resolving the evolutionary relationships within this group.
Purpose of the Study:
- To determine the phylogenetic relationships among four species of common voles: *M. kirgisorum*, *M. transcaspicus*, *M. arvalis*, and *M. rossiaemeridionalis*.
- To investigate the role of chromosomal rearrangements and molecular evolution in the speciation of these voles.
Main Methods:
- High-resolution GTG-banding patterns were compared to analyze karyotype similarities and chromosomal element rearrangements.
- Phylogenetic trees were constructed using karyotype data and mitochondrial cytochrome b gene sequences.
- FITCH and KITSCH computer programs were utilized for molecular phylogenetic analysis and divergence time estimation.
Main Results:
- Karyotype analysis indicated that the species share common chromosomal elements, with divergence likely arising from rearrangements.
- Two distinct karyotypic variants were proposed, potentially leading to *M. rossiaemeridionalis*/*M. transcaspicus* and *M. kirgisorum*/*M. arvalis*.
- Molecular phylogenetic analysis based on mitochondrial DNA provided an alternative tree, with divergence times estimated.
Conclusions:
- Both karyological and molecular data contribute to understanding vole phylogeny, though correlations require further investigation.
- The study proposes evolutionary routes for chromosomal divergence and speciation within the *Microtus* genus.
- This research provides insights into the complex evolutionary history of common voles.