Một kiểu di truyền qua RNA chưa từng được học!

[ruanhocon]

Có em đây ạ..

bai 1:


Genome-wide non-mendelian inheritance of extra-genomic information in Arabidopsis.
Lolle SJ, Victor JL, Young JM, Pruitt RE
Nature 2005 Mar 23
Links

Exceptional
F1000 Factor 13.3

[hr:e177884ed4]

1. Magnus Nordborg
University of Southern California, United States of America
GENOMICS & GENETICS

Hypothesis
New Finding

This paper reports what appears to be the transmission to offspring of genetic information not present in the parents but present in previous generations. The proposed mechanism is some form of RNA cache. It is not often one reads a paper that could make it necessary to revise most biology textbooks.

Evaluated 12 Apr 2005

Stephan Beck
Wellcome Trust Sanger Institute, United Kingdom
IMMUNOLOGY

Hypothesis
New Finding
Controversial

This article is interesting because it insinuates a novel mechanism for unorthodox non-mendelian inheritance. Using a mutant system in the plant Arabidopsis thaliana, the authors observed inheritance of allele-specific genomic DNA sequences that were not present in the parental genome but were present in the grandparental genome. Excluding obvious explanations such as contamination and gene conversion, the authors postulate the mechanism to be mediated by an unknown species of RNA using an 'ancestral RNA-sequence cache'. If confirmed, this finding presents a major discovery with wide-ranging implications.

Evaluated 8 Apr 2005


Philip Benfey
Duke University, United States of America
PLANT BIOLOGY

New Finding
Controversial

A new layer of genetic inheritance may have been uncovered in this report. A mutation that reverts at a very high frequency leads the authors to speculate that there is an "RNA genome" that maintains genetic information from previous generations and can be used to repair genomic lesions. The authors appear to have ruled out most trivial causes for their findings, including gene conversion or high mutation rate. Thus, although an RNA genome seems far-fetched, it is difficult to come up with a reasonable alternative to explain these fascinating results.

Evaluated 5 Apr 2005


Venkatesan Sundaresan
University of California, Davis, United States of America
PLANT BIOLOGY

Hypothesis
New Finding

This paper reports the amazing discovery of an unsuspected mechanism for correcting mutations using the hothead mutation in Arabidopsis. The mutations were restored to the grandparental allele, and a role for a DNA template was excluded, therefore RNA has been postulated as the template. The details of the mechanism, how universal it might be in eukaryotes, and why it has eluded detection previously are fascinating problems for future studies. The findings could also have important implications for biotechnology.

Evaluated 4 Apr 2005

Caren Chang
University of Maryland, United States of America
PLANT BIOLOGY

Hypothesis
New Finding

This paper reveals the surprising inheritance of allele-specific sequences not present in the genomes of either parent but present only in the genomes of earlier generations. This non-Mendelian inheritance pattern was revealed by the high frequency reversion of 11 different alleles in the organ fusion gene HOTHEAD in Arabidopsis thaliana. It is postulated that the mechanism involves stored RNA templates serving as molecular "memory" to repair chromosomal DNA sequences.

Martin Parniske
Ludwig Maximilians Universitaet, Germany
PLANT BIOLOGY

Hypothesis
New Finding
Controversial

In this important and groundbreaking paper, the authors propose a novel extrachromosomal mechanism of inheritance. High frequency of revertants at three independent positions in the HOTHEAD gene cannot be explained by gene conversion or high rates of localised random mutation. To explain their observations, the authors propose replicating double stranded RNA molecules as a cache for sequence information that can be transmitted over several generations.

Evaluated 31 Mar 2005

James Hu
Texas A & M University, United States of America
CHEMICAL BIOLOGY

New Finding

Lolle et al. report evidence for a cache of genetic information in Arabidopsis that reflects the previous genetic history of a plant. Plants mutant for the Hothead (HTH) locus show amazing genetic behavior. Selfing homozygous hth/hth plants give rise to a high frequency of gene conversions, both at HTH itself and, importantly, at several other homozygous ecotype-specific SNPs. In all of these cases, progeny appear that are heterozygous at loci that were homozygous in the selfed plants. This does not seem to be due to hypermutation. Alleles only appear that were present in the lineage giving rise to the plants, but not in the current generation. These results suggest a cache of allelic information that is transmissible; since Lolle et al. could not detect this information in the DNA, they suggest that the cache could take the form of RNAs that replicate in ways similar to the dsRNAs found in the mechanism of RNAi. The recovery of information from the cache has so far only been seen in hth/hth plants.

Evaluated 31 Mar 2005

John Bowman
University of California, Davis, United States of America
PLANT BIOLOGY

Hypothesis
New Finding

Non-Mendelian inheritance of extra-chromosomal genetic information in Arabidopsis is observed at a high level in a hothead mutant background, with genomic mutant alleles reverting to alleles not present in the parents, but present in grandparents or great-grandparents. The authors propose that the extra-genomic genetic information may be stored as an RNA cache representing ancestral alleles that is propogated from generation to generation. In times of stress, such an allele cache could be beneficial in facilitating a reversion to alleles of reproductively successful ancestors.

Evaluated 31 Mar 2005

Christian Hardtke
University of Lausanne, Switzerland
PLANT BIOLOGY

Hypothesis
New Finding

Once in a while a publication shakes the foundations of what we have learned in school; this paper is one of them. The authors followed up on a high frequency of revertants in homozygous lines of the Arabidopsis hothead mutant. They demonstrate through a number of elegant genetic experiments that these revertants have been altered non-randomly at the exact nucleotide of the original mutation, restoring the grand-parental wild type allele. They go on to show that such reversions occur globally throughout the genome of these mutants and can still be observed after several generations of homozygous mutant propagation. The authors postulate an RNA-based "genetic cache" that can direct restoration of ancestral alleles, possibly depending on stress conditions. So dig out your puzzling low penetrance mutants and have a look...

Evaluated 31 Mar 2005

Jose Luis Riechmann
California Institute of Technology, United States of America
PLANT BIOLOGY

Hypothesis
New Finding

This is a fascinating paper that provides compelling evidence for the inheritance of allele-specific DNA information that was not present in the chromosomal DNA of the parents, but rather in previous generations. Whereas the details of the molecular mechanism are largely unknown, it appears to be a genome-wide, template-dependent process, perhaps involving an uncharacterized class of functional RNA. This is a novel, non-mendelian mechanism of inheritance.

Evaluated 31 Mar 2005

James Carrington
Oregon State University, United States of America
PLANT BIOLOGY

Hypothesis
New Finding

This remarkable paper presents compelling evidence for a memory system that retains allele-specific information from previous generations, even if the parents lacked the allele. In loss-of-function hothead mutants of Arabidopsis, DNA polymorphisms on a genome-wide scale revert back to the allele present in grandparents (but missing in parents), presumably by a sequence-specific, non-DNA-based guide mechanism involving RNA. Might this multi-generational sequence cache be another role for the RNAi apparatus? The testable questions raised by these findings are almost as exciting as the results themselves!

Evaluated 31 Mar 2005

Marjori Matzke
Austrian Academy Of Sciences, Austria
PLANT BIOLOGY

Hypothesis
New Finding

This paper reports an unusual form of inheritance in Arabidopsis 'hothead' mutants, where DNA sequence information absent in the parent but present in previous generations reappears at high frequency in selfed progeny of homozygous mutant plants. The specificity of the observed DNA sequence changes led the authors to propose the existence of a genome-wide library of stable, heritable RNAs, which can be used for template-directed changes in DNA sequence. This process might have adaptive significance if alleles tested successfully in previous generations can be restored to the genome, allowing an organism to recover from a genotype that might be poorly suited to its present environment.

Evaluated 31 Mar 2005

Judy Wall
University of Missouri-Columbia, United States of America
MICROBIOLOGY

Hypothesis
New Finding
Controversial

This article describes an apparently new mechanism of genetic inheritance in plant cells that questions the predictable segregation patterns of alleles. Allele-specific DNA sequence information not present in the parental genomic DNA but present in earlier generations was shown to be inherited. An unrecognized RNA cache of sequences is proposed as a genetic reservoir for subsequent inheritance. Understanding the mechanism and the extent of the occurence of this phenomenon could elucidate a novel genetic transmission path.

Evaluated 30 Mar 2005

Kay Schneitz
Technical University of Munich, Germany
PLANT BIOLOGY

New Finding

This paper reports on the fascinating discovery that the Arabidopsis organ fusion mutant hothead (hth) can inherit allele-specific DNA sequence information not present in the genome of its parents but in previous generations. The authors provide evidence that this phenomenon is not restricted to the HTH gene but exists in several loci dispersed throughout the genome. The experiments indicate that a number of possibilites, such as seed contamination or gene conversion, do not account for the observations. While the mechanism is not understood, the authors postulate an RNA-based and template-directed process.

Evaluated 30 Mar 2005

Shigeru Iida
National Institute for Basic Biology, Japan
PLANT BIOLOGY

Hypothesis
New Finding

The authors described novel non-mendelian inheritance phenomena, in which reversions could be observed in the selfed progeny of mutants bearing homozygously recessive alleles when their recent ancestors had carried the corresponding wild-type allele. If the intriguing phenomena and the proposed mechanism were found to be a general nature of inheritance, it would also have impacts on our understanding of evolutionary processes because their model implies that, in the similar way as described for the wild-type allele in the paper, the mutant alleles in the recent ancestors can also be recovered in the selfed progeny of plants with the wild-type allele in the homozygous condition.

Evaluated 30 Mar 2005

Frank Lyko
German Cancer Research Center, Germany
GENOMICS & GENETICS

Hypothesis
New Finding

This paper describes fascinating details about non-mendelian inheritance events in Arabidopsis. The authors have analyzed the HOTHEAD mutant that shows an increased rate of mutant reversion. The results indicate that this phenomenon is mediated by retrieval of genetic information from extra-genomic templates, like an ancestral RNA cache.

Evaluated 24 Mar 2005
[hr:e177884ed4]

 

[Cao Xuân Hiếu]

Mời mọi ng đọc bản đầy đủ. Tôi đảm bảo là nếu phát hiện này tiến hành ở nước ta thì chẳng đời nào thằng Nature nó tin. Nếu điều này đúng thì tôi tin rằng đã có ối nhà khoa học đã vứt kết quả thí nghiệm kiểu này đi từ lâu rồi.

 

[Cao Xuân Hiếu]

Vụ này cao cấp quá các bác ạ. Không có đại gia nào đứng cầm trịch vài bài thì dễ tắt điện lắm.

Nếu mọi ng đều có hứng thú thì chúng ta "dũng cảm" tiến lên.

Bài học mà chúng ta thấy được từ bài báo trên là chiến lược bảo vệ tính chính xác trong khoa học của nó. Ai đọc đầu tiên cũng nghĩ rằng chắc nhóm này làm sai ở bước nào đó.

Vậy chúng ta cùng in bài báo ra và "xé " nó ra từng mảnh để xem nhóm tác giả này đã phải đối mặt với những vấn đề "nghi ngờ" tính chính xác ntn và "cách giải quyết" của họ là gì?

Thí nghiệm này được thực hiện bởi những kỹ thuật mà các PTN ở VN đều có thể làm và kiểm chứng. Vậy cái hay của nó là "strategy".

 

[Trần Hoàng Dũng]

vietbio cứ làm đi, mọi người hưởng ứng.

Nói chuyện khoa học VN thấy buồn quá, ta còn kô tin ta chứ nói gì thế giới.

Strategy à, làm khoa học ai chẳng nghĩ đến cái này, nhưng strategy của ta là làm sao dẫn đến: ứng dụng thực tế để đề tài kô xếp ngăn kéo, chứ nếu viết strategy để lấy kiến thức khoa học thì ai mà duyệt đề tài để lấy tiền đi ... nhậu.

Do vậy đề tài khoa học của ta luôn kết thúc bằng việc:

- hằng trăm hộ nông dân ứng dụng kết quả
- nhiều nhà máy xí nghiệp mong được chuyển giao kết quả nghiên cứu
- đề tài giải quyết tình hình thực tiễn cấp bách của địa phương

anh so much more.