La fusione Robertsoniana (Rb) di cromosomi acrocentrici è uno degli eventi più frequenti capaci di diversificare il cariotipo. Ciononostante il meccanismo molecolare di tale evento non è ancora chiaro. Nella presente Nota viene suggerita l'ipotesi che, durante la sintesi del DNA, l'appaiamento di basi di sequenze omologhe su filamenti parentali 5' e 3' (di due diversi cromosomi le cui coordinate polari siano anti-rotate) porti alla formazione di un eteroduplex. Il taglio e la chiusura della regione di DNA riordinata (da parte di una topoisomerasi) unirebbe in un metacentrico i due cromosomi acrocentrici. L'analisi della organizzazione del genoma in relazione alla struttura del cariotipo in diversi gruppi animali da sostegno alla idea che i cromosomi possano scambiarsi parti, o intere braccia, in siti ove la sequenza di basi mostri un alto grado di omologia.
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Con il contributo del Ministero per i Beni e le Attività Culturali