Tag: cytogenetics

Mosquito populations give a new insight into the role of Caucasus in evolution

We know that the Caucasus is a relatively large mountainous region, situated between Black and the Caspian seas. In its turn, it is divided into three subregions: Ciscaucasia, Greater Caucasus and Transcaucasia, also known as South Caucasus.

A closer look into the chromosome structure of mosquito larvae of a curious group of species (Chironomus “annularius” sensu Strenzke (1959)), collected from the three localities, has allowed Dr Mukhamed Karmokov of the Tembotov Institute of Ecology of Mountain territories at the Russian Academy of Science to figure out how the specificity of the Caucasian region has simultaneously unified its fauna geographically, yet has divided it evolutionarily. His paper is published in the open access journal Comparative Cytogenetics.

Having collected a sufficient amount of mosquito larvae, the researcher managed to study the chromosome structure, rearrangements and possible peculiarities of the separate Caucasian populations, in order to compare them.

Additionally, he analysed their relations to earlier known populations from Europe, Siberia, Kazakhstan and North America.

Amongst the curious peculiarities Karmokov identified in the chromosome structure of the studied larvae were some rearrangements which appear unique to Caucasus. Furthermore, he found that despite the close geographic proximity, the genetic distance between the Caucasian populations is quite significant, even While not enough to determine them as separate species, it could prove them as separate subspecies.

In conclusion, the scientist notes that the obtained data confirm that the Caucasian populations of the studied species have complex genetic structure and provide evidence for microevolution processes in the region.

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Original source:

Karmokov MKh (2018) Karyotype characteristics and chromosomal polymorphism of Chironomus “annularius” sensu Strenzke (1959) (Diptera, Chironomidae) from the Caucasus region. Comparative Cytogenetics 12(3): 267-284. https://doi.org/10.3897/CompCytogen.v12i3.25832

The Caucasus as an ‘island’ in the ‘sea’ of steppes: New insights in mosquito evolution

From a geographical point of view, the Caucasus is far from an island or even a peninsula, being a relatively big mountainous region appearing as a fence at the border of Europe and Asia, situated between the Black and the Caspian seas. However, a study into the chromosome structure of mosquito larvae of the species Glyptotendipes salinus, living by a saltwater lake in the foothills of the Caucasus, suggests that the region could be imagined as an “island” in the “sea” of steppes.

Scientists Dr Mukhamed Karmokov, Tembotov Institute of Ecology of Mountain territories, Russian Academy of Science, and Dr Azamat Akkizov, Institute of Biomedical Problems, RAS, and Center of Medico-Ecological Researches, have their paper, where they describe the Caucasian population of the species, published in the open access journal Comparative Cytogenetics.

Earlier, it has been known that in the Tambukan Lake, located at the foothills of the Caucasus Mountains, lives at least one of the representatives of the genus Glyptotendipes, more precisely, the species G. salinus. Actually, the process of studying the fauna of the genus in the Caucasus region has just began and many questions have remained unclear.

During their research, the authors collected a sufficient amount of larvae of G. salinus that made it possible to study the chromosome structure, rearrangements and peculiarities of the Caucasian population of the species. In addition, the authors tried to understand how the population relates to the previously studied ones, living in the Altai region of Russia and Kazakhstan.

Researchers found interesting, some of them even striking, peculiarities in the chromosome structure and morphology of the larvae from Caucasus. Namely, they found four new chromosome rearrangements, likely unique for the Caucasus. Also, some of the chromosome characters were most similar to the mosquitoes from Altai, while others — to the population in Kazakhstan. The most curious difference of the Caucasian larvae in comparison to data from earlier studies was that they were twice as short.

In conclusion, the authors note that from the obtained data it could be deduced that that the Caucasian population had undergone a significant divergence, or even that it represents a subspecies.

Also, it turns out that the Caucasus itself is a relatively isolated and complex region in terms of microevolution. “The Caucasus, in some sense, can be imagined as a relatively isolated territory, a special place, where evolution has made some unexpected twists,” they say.

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Original source:

Karmokov MKh, Akkizov AY (2016) Karyotype characteristics, larval morphology and chromosomal polymorphism peculiarities of Glyptotendipes salinus Michailova, 1983 (Diptera, Chironomidae) from Tambukan Lake, Central Caucasus. Comparative Cytogenetics 10(4): 571-585. https://doi.org/10.3897/compcytogen.v10i4.9400