近日，中國(guó)農(nóng)業(yè)大學(xué)農(nóng)學(xué)與生物技術(shù)學(xué)院金危危教授等研究人員發(fā)表在《美國(guó)國(guó)家科學(xué)院院刊》上的文章入選了Nature亮點(diǎn)推薦,，在這篇文章中,，研究人員在葫蘆科植物中發(fā)現(xiàn)了一種著絲粒復(fù)位，而且通過(guò)比較熒光原位雜交圖譜等實(shí)驗(yàn)分析,，研究人員也發(fā)現(xiàn)葫蘆科植物著絲粒激活和休眠都與異染色體大量的遺失和獲得有密切的關(guān)系,。
研究人員在葫蘆科植物中發(fā)現(xiàn)了一種著絲粒復(fù)位,，著絲粒是許多高等真核生物染色體的重要結(jié)構(gòu)域之一，它的最內(nèi)層是由串聯(lián)重復(fù)的衛(wèi)星DNA及其側(cè)翼富集的中度重復(fù)元件組成,。在整個(gè)真核生物類(lèi)群中,，不同物種間著絲粒的DNA序列千差萬(wàn)別，但其功能卻相當(dāng)保守,，可確保在有絲分裂和減數(shù)分裂過(guò)程中染色體的正確分離和傳遞,。
在進(jìn)化過(guò)程中真核生物著絲粒的DNA序列會(huì)發(fā)生遷移，從而導(dǎo)致染色體形態(tài)學(xué)和組型發(fā)生大幅改變,，而著絲粒復(fù)位現(xiàn)象在許多哺乳動(dòng)物基因組進(jìn)化過(guò)程中都已被發(fā)現(xiàn),，并且證明在哺乳動(dòng)物基因組進(jìn)化過(guò)程中扮演著重要的角色。在這篇文章中,，研究人員在葫蘆科植物中發(fā)現(xiàn)了一種著絲粒復(fù)位,，而且通過(guò)比較熒光原位雜交圖譜等實(shí)驗(yàn)分析，研究人員也發(fā)現(xiàn)葫蘆科植物著絲粒激活和休眠都與異染色體大量的遺失和獲得有密切的關(guān)系,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS August 18, 2009, doi: 10.1073/pnas.0904833106
Centromere repositioning in cucurbit species: Implication of the genomic impact from centromere activation and inactivation
Yonghua Hana,b,1, Zhonghua Zhangc,1, Chunxia Liua, Jinhua Liua, Sanwen Huangc, Jiming Jiangd and Weiwei Jina,2
aNational Maize Improvement Center of China, Key Laboratory of Crop Genetic Improvement and Genome of Ministry of Agriculture, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100094, China;
bState Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
cKey Laboratory of Horticultural Crops Genetic Improvement of Ministry of Agriculture, Sino-Dutch Joint Lab of Horticultural Genomics Technology, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; and
dDepartment of Horticulture, University of Wisconsin-Madison, Madison, WI 53706
The centromere of an eukaryotic chromosome can move to a new position during evolution, which may result in a major alteration of the chromosome morphology and karyotype. This centromere repositioning phenomenon has been extensively documented in mammalian species and was implicated to play an important role in mammalian genome evolution. Here we report a centromere repositioning event in plant species. Comparative fluorescence in situ hybridization mapping using common sets of fosmid clones between two pairs of cucumber (Cucumis sativus L.) and melon (Cucumis melo L.) chromosomes revealed changes in centromere positions during evolution. Pachytene chromosome analysis revealed that the current centromeres of all four cucumber and melon chromosomes are associated with distinct pericentromeric heterochromatin. Interestingly, inactivation of a centromere in the original centromeric region was associated with a loss or erosion of its affixed pericentromeric heterochromatin. Thus, both centromere activation and inactivation in cucurbit species were associated with a gain/loss of a large amount of pericentromeric heterochromatin.
