'Hidden' differences of chromosome organization become visible

August 25, 2011
This is the Italian pine vole, Microtus savii. Credit: Alexandra M.R. Bezerra

Why different species have dissimilar sets of chromosomes? Why the differentiated species often conserve apparently identical chromosome complements? Furthermore, why, while chromosome rearrangements can considerably change the course of species evolution, certain variation among individuals and populations of some species persists indefinitely? Such questions motivate researchers to compare chromosomes in closely related species.

To understand the nature of chromosome changes in the voles Microtus savii, researchers from the Rome State University "Sapienza" launched a molecular cytogenetic study. Three of the five Italian forms of pine voles showed remarkable differences in chromosomal distribution of two molecular markers. Analyzing these data and weighing them against previously obtained , the authors expect to improve the taxonomy of these rodents and to track the pathway of their chromosomal evolution.

The Italian pine voles have long been known as a "species complex", namely the Microtus savii complex. The group includes five "forms": "savii", "brachycercus", "nebrodensis", "niethammericus", and "tolfetanus", distributed throughout the Apennine peninsula. The most widely dispersed is "savii"; "brachycercus" lives in Calabria, "niethammericus" inhabits the Southeast part of the peninsula, while "nebrodensis" is restricted to Sicily.

These ground voles have evolved at different times either with or without chromosomal rearrangements. Chromosomal distribution of specific genes and can help to distinguish between related species with very similar, apparently identical, . By localization of such molecular "markers" on chromosomes, or so-called "physical mapping", researchers evidence differences that are normally invisible in microscope. These differences indicate "hidden" processes of chromosome diversification.

Explore further: X chromosome exposed

More information: Gornung E, Bezerra AMR, Castiglia R (2011) Comparative chromosome mapping of the rRNA genes and telomeric repeats in three Italian pine voles of the Microtus savii s.l. complex (Rodentia, Cricetidae). Comparative Cytogenetics 5(3): 247. doi: 10.3897/CompCytogen.v5i3.1429

Related Stories

X chromosome exposed

May 29, 2008

Researchers from the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, and the EMBL-European Bioinformatics Institute (EMBL-EBI) in Hinxton, UK, have revealed new insights into how sex chromosomes are regulated. ...

Discovering the bigger picture in chromosomes

July 6, 2011

By mapping various genomes onto an X-Y axis, a team comprised mostly of Kansas State University researchers has found that Charles Darwin and a fruit fly -- among other organisms -- have a lot in common genetically.

Chromosome number changes in yeast

July 21, 2011

Researchers from Trinity College Dublin have uncovered the evolutionary mechanisms that have caused increases or decreases in the numbers of chromosomes in a group of yeast species during the last 100-150 million years. The ...

B chromosomes affect sex determination in cichlid fishes

August 18, 2011

B chromosomes have a functional effect on sex determination in a species of cichlid fishes from Lake Victoria, according to a study by Japanese researchers to be published in open-access journal PLoS Genetics on August 18th, ...

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.