|JACOBS UNIVERSITY BREMEN
Variation in chromosome number as »normal« state:
Günther Zupanc, Professor of Neurobiology at Jacobs University, and his co-workers at the Scripps Research Institute in La Jolla/California and the University of Leipzig for the first time provided evidence that even a profound deviation from the number of chromosomes typical for a species does not necessarily result in physiological or behavioural deficiencies of the organism. Analysis of newly generated neurons in the brains of the healthy adult knifefish showed, that approximately 80 % of the cells deviate from the “normal” number of 22 chromosomes with aberrations of up to 70 %. The study is published in the current online express issue of Developmental Neurobiology (2007: doi: 10.1002/dneu.20365)
Established scientific doctrine for a long time has assumed that any cell of an organism contains identical genetic information encoded by a species-specific number of chromosomes, with the exception of sperms and eggs with half the number. Humans, for example, have a total of 46 chromosomes – 22 pairs of autosomal chromosomes and two sex chromosomes. Aberrations of this number were thought to usually result in severe diseases. Down syndrome, for example, which causes physical and mental disabilities in humans, is caused by three instead of two chromosomes No 21 in all cells of the body. Even if only part of the body’s cells exhibits this aberration, a phenomenon referred to as “mosaicism”, the severity of the symptoms is similar. The notion that an aberrant number of chromosomes is associated with severe defects of the organism has been reinforced by more recent studies which showed that most, if not all, tumor cells exhibit marked variations in chromosome number among their cells.
Author: Dr. Kristin Beck. Last updated on 15.04.2007. © 2007 Jacobs University Bremen, Campus Ring 1, 28759 Bremen. All rights reserved. No unauthorized reproduction. http://www.jacobs-university.de. For all general inquiries, please call the university at +49 421 200-40 or mail to firstname.lastname@example.org.