SATELLITE ASSOCIATIONS IN HUMAN ACROCENTRIC CHROMOSOMES: AN INSIGHT INTO THE EVOLUTION OF BIARMED CHROMOSOMES

摘要

Human acrocentric chromosomes are frequently found in satellite association (SA). Though many studies concerning SAs have been made, the results are conflicting and are often inconsistent. In view of this, SA were analysed in dyslexic, congenital heart disease (CHD) and control groups to study the ability of their nucleolus-organizing chromosomes to form satellite association pattern in G-banded lymphocyte metaphases. More than eleven thousand metaphases from control, dyslexic and congenital heart disease individuals were examined and the analysis revealed the following: (a) SA is more frequent in dyslexics compared to controls and congenital heart disease patients, (b) heterologous acrocentrics are more frequently associated than homologous pairs,(c) association between D-G acrocentrics are more prevalent than D-D or G-G groups, (d) large acrocentrics associate preferably with small acrocentrics than between small or large acrocentrics, and (e) chromosome 21 is more frequently involved in SA thanthe other acrocentrics. Thus, the acrocentric chromosomes are not stable as metacentric chromosomes and they are susceptible to different chromosomal changes that ultimately leads to dominance of metacentric chromosomes in the human karyotype.