近日，中国农业大学农学与生物技术学院金危危教授等研究人员发表在《美国国家科学院院刊》上的文章入选了Nature亮点推荐，在这篇文章中，研究人员在葫芦科植物中发现了一种着丝粒复位，而且通过比较荧光原位杂交图谱等实验分析，研究人员也发现葫芦科植物着丝粒激活和休眠都与异染色体大量的遗失和获得有密切的关系。
研究人员在葫芦科植物中发现了一种着丝粒复位，着丝粒是许多高等真核生物染色体的重要结构域之一，它的最内层是由串联重复的卫星DNA及其侧翼富集的中度重复元件组成。在整个真核生物类群中，不同物种间着丝粒的DNA序列千差万别，但其功能却相当保守，可确保在有丝分裂和减数分裂过程中染色体的正确分离和传递。
在进化过程中真核生物着丝粒的DNA序列会发生迁移，从而导致染色体形态学和组型发生大幅改变，而着丝粒复位现象在许多哺乳动物基因组进化过程中都已被发现，并且证明在哺乳动物基因组进化过程中扮演着重要的角色。在这篇文章中，研究人员在葫芦科植物中发现了一种着丝粒复位，而且通过比较荧光原位杂交图谱等实验分析，研究人员也发现葫芦科植物着丝粒激活和休眠都与异染色体大量的遗失和获得有密切的关系。（生物谷Bioon.com）
生物谷推荐原始出处：
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.
