生物谷报道：单独的染色体是双螺旋分子。正处于分离状态的染色体是双生分子：两团遗传物质靠一段名为着丝粒（centromere）的DNA连接在一起。着丝粒指导染色体分离，确保新生细胞DNA含量正常。但多年来，人们对着丝粒进化细节却一无所知。最近出现了一种颇具争义性的理论：着丝粒来自于古老染色体的末端。
据《科学》报道，研究者对着丝粒是一次性进化还是多次进化有争议。即使源头是独立的，各种有机体在这些DNA链的排序上也会变化多端。然而着丝粒始终起着相同的作用：它们一开始把新形成的染色体组合起来，然后当细胞分裂时协调锚定蛋白纤维使染色体分离。此外，所有单一源头分裂的有机体蛋白质进化在此过程中的是相同的。
原始出处：
Science 13 April 2007:
Vol. 316. no. 5822, pp. 243 - 246
DOI: 10.1126/science.1140615
Evolutionary Formation of New Centromeres in Macaque
Mario Ventura,1* Francesca Antonacci,1* Maria Francesca Cardone,1 Roscoe Stanyon,2 Pietro D'Addabbo,1 Angelo Cellamare,1 L. James Sprague,3 Evan E. Eichler,3 Nicoletta Archidiacono,1 Mariano Rocchi1
A systematic fluorescence in situ hybridization comparison of macaque and human synteny organization disclosed five additional macaque evolutionary new centromeres (ENCs) for a total of nine ENCs. To understand the dynamics of ENC formation and progression, we compared the ENC of macaque chromosome 4 with the human orthologous region, at 6q24.3, that conserves the ancestral genomic organization. A 250-kilobase segment was extensively duplicated around the macaque centromere. These duplications were strictly intrachromosomal. Our results suggest that novel centromeres may trigger only local duplication activity and that the absence of genes in the seeding region may have been important in ENC maintenance and progression.
1 Department of Genetics and Microbiology, University of Bari, 70126 Bari, Italy.
2 Department of Animal Biology and Genetics, University of Florence, Florence 50125, Italy.
3 Howard Hughes Medical Institute, Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA.
* These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail: rocchi@biologia.uniba.it
