The specific number of chromosomes is one of the defining characteristics of a species. Whilst the common fruit fly carries 8 chromosomes, the genome of bread wheat counts 42 chromosomes. In comparison, the human genome is made out of a total of 46 chromosomes. However, about 15% of all eukaryotic species additionally carry supernumerary chromosomes referred to as "B chromosomes". Other than the essential chromosomes of the genome, B chromosomes are expendable and often preferentially inherited. This leads to a transmission advantage for B chromosomes called "chromosome drive". To date, little knowledge exists about the mechanisms behind this phenomenon. Researchers from the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben have now been able to decipher the mechanisms behind the drive of B chromosomes in the goatgrass Aegilops speltoides. The novel insights in the workings of chromosome drive were recently published in New Phytologist.
* This article was originally published here
