生物谷報道：單獨的染色體是雙螺旋分子。正處于分離狀態(tài)的染色體是雙生分子：兩團遺傳物質(zhì)靠一段名為著絲粒（centromere）的DNA連接在一起,。著絲粒指導染色體分離，確保新生細胞DNA含量正常,。但多年來，人們對著絲粒進化細節(jié)卻一無所知,。最近出現(xiàn)了一種頗具爭義性的理論：著絲粒來自于古老染色體的末端,。
據(jù)《科學》報道,，研究者對著絲粒是一次性進化還是多次進化有爭議,。即使源頭是獨立的，各種有機體在這些DNA鏈的排序上也會變化多端,。然而著絲粒始終起著相同的作用：它們一開始把新形成的染色體組合起來,，然后當細胞分裂時協(xié)調(diào)錨定蛋白纖維使染色體分離。此外,，所有單一源頭分裂的有機體蛋白質(zhì)進化在此過程中的是相同的,。
原始出處：
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: [email protected]
