遗传重组（它涉及DNA股的断开和重接以产生新的基因组合）是真核细胞生物中的一种基本的生物学过程。在哺乳动物减数分裂的时候，在这一专门化的细胞分裂过程中，来自母系和父系的染色体被一分为二并产生出精子细胞和卵子细胞，而重组过程则将同源染色体的不同部分连接在了一起，从而导致了后代中的基因变化。
在2010年2月12日刊的《科学》杂志中，有3个研究小组报告发现了控制发生在被称作“热点”的优先染色体位置的基因重组程度的哺乳动物基因（含有9或Prdm9的PR结构域）。
Parvanov等人发现，在小鼠中，*Prdm9*（它编码的是一种功能为组蛋白甲基转移酶的锌指蛋白）会在雄性和雌性动物的早期减数分裂时表达，而其表达的不足会导致雌雄两性的不育。研究人员还对小鼠和人类的该基因进行了测序并对其序列变异进行了分析。
Baudat等人将小鼠和人体中不同的*Prdm9*变异株和PRDM9 蛋白变异株与预计的不同DNA序列特异性和基因组中不同模式的热点“使用”进行了相关研究。
最后，Myers 等人对人类和黑猩猩基因组中的重组热点位置进行了比较并发现了一个过去与40%的人类热点（而PRDM9蛋白质就是与其结合的）有关的序列基元；而该重组过程导致了一种自我破坏的驱动力，使得该吸收热点的序列基元从我们的基因组中被清除了出去。
在一篇附随的Perspective中，Cheung写道，这些发现开启了人们了解成功配子形成的平衡与维护基因多元性的大门。（生物谷Bioon.com）
生物谷推荐原始出处：
Science 12 February 2010: DOI: 10.1126/science.1181495
Prdm9 Controls Activation of Mammalian Recombination Hotspots
Emil D. Parvanov, Petko M. Petkov,* Kenneth Paigen*
Mammalian meiotic recombination, which preferentially occurs at specialized sites called hotspots, ensures the orderly segregation of meiotic chromosomes and creates genetic variation among offspring. A locus on mouse chromosome 17, which controls activation of recombination at multiple distant hotspots, has been mapped within a 181-kilobase interval, three of whose genes can be eliminated as candidates. The remaining gene, Prdm9, codes for a zinc finger containing histone H3K4 trimethylase that is expressed in early meiosis and whose deficiency results in sterility in both sexes. Mus musculus exhibits five alleles of Prdm9; human populations exhibit two predominant alleles and multiple minor alleles. The identification of Prdm9 as a protein regulating mammalian recombination hotspots initiates molecular studies of this important biological control system.
The Jackson Laboratory, Bar Harbor, ME 04609, USA.
Science 12 February 2010: DOI: 10.1126/science.1183439
PRDM9 Is a Major Determinant of Meiotic Recombination Hotspots in Humans and Mice
F. Baudat,1,* J. Buard,1,* C. Grey,1,* A. Fledel-Alon,2 C. Ober,2 M. Przeworski,2,3 G. Coop,4 B. de Massy1,
Meiotic recombination events cluster into narrow segments of the genome, defined as hotspots. Here, we demonstrate that a major player for hotspot specification is the Prdm9 gene. First, two mouse strains that differ in hotspot usage are polymorphic for the zinc finger DNA binding array of PRDM9. Second, the human consensus PRDM9 allele is predicted to recognize the 13-mer motif enriched at human hotspots; this DNA binding specificity is verified by in vitro studies. Third, allelic variants of PRDM9 zinc fingers are significantly associated with variability in genome-wide hotspot usage among humans. Our results provide a molecular basis for the distribution of meiotic recombination in mammals, in which the binding of PRDM9 to specific DNA sequences targets the initiation of recombination at specific locations in the genome.
1 Institut de Génétique Humaine, UPR1142, CNRS, Montpellier, France.
2 Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
3 Howard Hughes Medical Institute, University of Chicago, Chicago, IL 60637, USA.
4 Department of Evolution and Ecology and the Center for Population Biology, University of California, Davis, CA 95616, USA.
Science 12 February 2010: DOI: 10.1126/science.1182363
Drive Against Hotspot Motifs in Primates Implicates the PRDM9 Gene in Meiotic Recombination
Simon Myers,1,2,*, Rory Bowden,1,2,* Afidalina Tumian,1 Ronald E. Bontrop,3 Colin Freeman,2 Tammie S. MacFie,4, Gil McVean,1,2, Peter Donnelly1,2,
Although present in both humans and chimpanzees, recombination hotspots, at which meiotic crossover events cluster, differ markedly in their genomic location between the species. We report that a 13–base pair sequence motif previously associated with the activity of 40% of human hotspots does not function in chimpanzees and is being removed by self-destructive drive in the human lineage. Multiple lines of evidence suggest that the rapidly evolving zinc-finger protein PRDM9 binds to this motif and that sequence changes in the protein may be responsible for hotspot differences between species. The involvement of PRDM9, which causes histone H3 lysine 4 trimethylation, implies that there is a common mechanism for recombination hotspots in eukaryotes but raises questions about what forces have driven such rapid change.
1 Department of Statistics, Oxford University, 1 South Parks Road, Oxford OX1 3TG, UK.
2 Wellcome Trust Centre for Human Genetics, Oxford University, Roosevelt Drive, Oxford OX3 7BN, UK.
3 Department of Comparative Genetics and Refinement, Biomedical Primate Research Center, Lange Kleiweg 139 2288 GJ, Rijswijk, Netherlands.
4 Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
