Centromeres are the basic unit for chromosome inheritance, but their evolution is highly dynamic. Both the centromeric histone protein (cenH3), as well as the underlying DNA sequence that forms the centromere (that is, the centromeric satellite DNA) vary among species. Centromere repeats have been proposed to act as selfish genetic elements by driving non-Mendelian chromosome transmission during female meiosis, thus prodding the rapid evolution of centromeric proteins to restore fair segregation. In addition to their primary sequence, the position of centromeres along the chromosome varies widely as well and results in diverse karyotypes across species.
We use the obscura group of Drosophila to study centromere evolution. Flies in this clade show multiple transitions from acrocentric to metacentric chromosomes, and vice versa.
Centromeres are formed de novo in euchromatic regions
Bracewell R, Chatla K, Nalley MJ & Bachtrog D (submitted). Dynamic turnover of centromeres drives karyotype evolution in Drosophila.