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Klosneuviruses (Giant Virus): Contradict the theory of virus as fourth domain of life alongside Bacteria, Eukaryotas and Archean

Klosneuviruses (Giant Virus): Contradict the theory of virus as fourth domain of life alongside Bacteria, Eukaryotas and Archean
An illustration of what a Klosneuvirus might look like. Credit: Ella Maru Studio

Klosneuviruses (Giant Virus): Contradict the theory of virus as fourth domain of life alongside Bacteria, Eukaryotas and Archean

Fourth domain of life :- Evolutionary biologists have never known what to make of viruses, arguing over their origins for decades. But a newly discovered group of giant viruses, called Klosneuviruses, could be a ‘missing link’ that helps to settle the debate — or provoke even more discord.

It is Mystery for biologists that what to make of viruses, it main debate topic for decades. Newly discovery of Giant Virus group also called Klosneuviruses, could be help to know more about this mystery and help to settle the debate.

Mimiviruses, a giant viruses group found by the researchers in 2003, with genes that suggested their anscestors could live outside of a host cell. The discovery split researchers into two camps. One group thinks viruses started out as self-sufficient organisms that became trapped inside other cells, eventually becoming parasitic and jettisoning genes they no longer needed. Another group views viruses as particles that snatched genetic material from host organisms over hundreds of millions of years.

Latter idea supported by the latest study published on 6 April 2017 in Science, that viruses are made up a patchwork of stolen parts. But it has already sparked controversy and is unlikely to settle the raucous debate.

After the Mimivirus discovery, some researchers developed a theory that put viruses near the root of the evolutionary tree. They proposed that viruses comprised a ‘fourth domain’ alongside bacteria, eukaryotes — organisms whose cells contain internal structures such as nuclei — and bacteria-sized organisms called archaea.

Mimiviruses, which at 400 nanometres across are about half the width of an E. coli cell and can be seen under a microscope, were unique in that they contain DNA encoding the molecules that translate RNA messages into proteins. Normal viruses make their host cells produce proteins for them.

The team that discovered Mimiviruses thought the virus’ ability to make their own proteins suggested that these viral giants descended from ancient free-living cell type that may no longer exist2. “They reinitiated the debate about the living nature of viruses, and of their relationship with the ‘cellular’ world,” says evolutionary biologist Jean-Michel Claverie of Aix-Marseille University in France, a co-author of the original Mimivirus paper.

Filling in the gaps

The question could be resolved by comparing genome sequences from viruses with those of their eukaryotic hosts. Mimiviruses contain too few eukaryotic-like genes to perform a statistical analysis that could determine their evolutionary relationships. The difficulty is compounded by the fact that viral genomes mutate very quickly.

Klosneuviruses may fill this gap. Their genomes contain code for dozens of enzymes and other molecular machinery used in making proteins. Some of these parts have never been seen before in any virus, including Mimiviruses.

“They’re kind of this missing link we haven’t had before,” says study co-author Tanja Woyke, a microbiologist at the Joint Genome Institute in Walnut Creek, California.

Woyke and her colleagues discovered the Klosneuviruses by accident while studying how bacteria break down sewage at a treatment plant in Austria. They sequenced the genomes in their samples to identify the organisms present, and found four genomes similar to those of Mimiviruses.

Using sophisticated software to trace the evolutionary history of their mystery genomes, the researchers found that the translation genes seemed to have been picked up one by one over hundreds of millions of years. This evidence supports the idea that viruses stole parts of their genomes, they say. It’s possible, however, that Mimiviruses and Klosneuviruses originated in different ways, making both ideas on viral origins possible, says Frederik Schulz, a bioinformatician at the Joint Genome Institute and a co-author on the new study.

Debating domains

It’s unclear which eukaryotic organisms donated their genes to the Klosneuvirus group. And because they haven’t identified the host, the researchers can’t grow the virus yet. The viruses do not seem to infect the same type of amoeba as Mimivirus and other known giant viruses.

Claverie points out that the majority of the Klosneuviruses’ translation machinery does not match that of any other known organism. And he worries that the computational model used to infer the viruses’ ancestry could pick up leftover pieces of DNA in the sample, potentially contaminating the data. “I am waiting to see a real virus isolated with its host in a tube, before I would believe any of their evolutionary interpretations,” he says.

David Moreira, an evolutionary biologist at the University of Paris South, doesn’t think that’s necessary. He says that plenty of evolutionary work can be done on a genome alone, and he is glad to see more papers coming to the conclusion that viruses are not a fourth domain of life.

Mimivirus co-discover Didier Raoult, a microbiologist at Aix-Marseille University, says this latest discovery won’t settle the debate, but it’s a nice find nevertheless. “We’re finding a part of the world that has been completely ignored and need to be patient.”

Recommended book list for UPSC CDS by Toppers

Recommended UPSC CDS Book List
  1. Pathfinder CDS Examination Conducted by UPSC
Pathfinder CDS Civil defence services

This is, hands down, the best book for CDS preparation. The book has been divided into 3 Sections and further sub-divided into various other topics. This is definitely one of the best CDS preparation books, and I recommend it for the serious CDS aspirant.

For CDSE aspirants, as I am one of these, the written book is great and complete in its contents. The only drawback may be the mistakes in typing. Although once you are practising queries you shall be in a position to conveniently find the typing errors. Other than that, there is absolutely no drawback in this content and overall.

And the idea provided for general research and on additional topics is also extremely good.

With enough example for every topics throughout the written book, one can practice easily in depth each one of the topic that will come in the CDS exam.

The Mathematics section is further divided into 28 chapters like:

  • · Number System
  • · Time & Distance
  • · Percentage
  • · Profit & Loss
  • · Logarithm
  • · Rational Expressions
  • · Linear Equations
  • · Set Theory
  • · Height & Distance
  • · Triangles
  • · Circle
  • · Locus
  • · Statistics and more
  • The English section has been divided into 9 chapters like:
  • · Spotting the Errors
  • · Vocabulary
  • · Synonyms
  • · Antonyms
  • · Idioms & Phrases
  • · Comprehension

2. CDS 10 Years Topic-wise Solved Papers 2007-2016 with free GK E-books

CDS 10 Years Topic-wise Solved Papers

Only when you have studied well and you intend to resolve the kind of questions asked in the CDS exam, buy this CDS exam book. The book contains two question papers of recent CDS examination at the beginning. The rest of the questions from 2007-2016 are further divided within their particular chapters. The book contains only queries and answers(with description). On the next page, you will notice the ‘Access code’ browse the guidelines their and you may get your free e-book.

3. Chapterwise Section Wise Solved Papers CDS Combined Defence Services Examination

Chapterwise-Sectionwise Solved Papers CDS (Combined Defence Services examination)

It is some sort of practice book where you have lots of solved issue in a systematic way covering each subject. It doesn’t have theory, so I suggest buying this CDS exam book once you are well clear of the concepts of the topics that will be asked in the CDS exam.

How exactly to Prepare English for CDS Test?

The majority of the students fear the English section and usually start searching an ideal answer of how exactly to prepare for the CDS English Paper? English question paper includes 120 questions of 100 marks with the exact time duration of 02 hours. Through this paper, the examiner tests your simple English skills in a lot of ways through various types of Grammar and Vocabulary questions.

First, go through the entire CDS English Syllabus. Following is the complete syllabus for the English section of the CDS exam.

To get ready for English, develop the habit of reading. You can improve your reading habit via many resources like English Newspapers, Mags, Notes, books etc. and in addition improve your English writing, speaking, and listening habits. Make new term lists every day and try to utilise it in lots of sentences. Also, may sign up for English speaking classes as well.

Divide all sections and plan one by one.

Buy some CDS exam books for English to clear the concepts. I suggest the following book for improving your English.

4. DESCRIPTIVE ENGLISH (For All Competitive Examinations)

Descriptive English for Competitive Examination

How to Prepare for the General Knowledge (GK) section for CDS Exam?

CDS GK Paper questions include mainly topics from Constitution, History, Economy, Geography, Politics, Navy & Military and Current affairs etc. Again, develop a habit of reading the newspaper daily.

Additionally, buy some CDS preparation books that cover the current affairs. I recommend the following book fod CDS GK preparation.

5. The Mega Yearbook 2017 – Current Affairs & General Knowledge for Competitive Exams

The Mega Year Book 2017 by Disha Publication

How to Prepare for the Math section for CDS Exam?

Make a list on important formulas, theorems and tips check some of here Geometry formulas for Circle, Rectangle, Square, tangents etc. Speed Distance and Time related questions, Math Formula For Area & surface area, Math Formula For Volume, Maths Formulas Of Number System etc to prepare for CDS.

Practise more and more sums from each topic, and you will pretty much have this section sorted for the CDS exam.

Additionally, I recommend the following CDS exam book for the Math section.

6. Algebra for SSC (Algebra for SSC)

Algebra for SSC

Study Plan for CDS when 2 months are left

  • Please refrain from learning new topics.
  • If you haven’t yet practised the previous year’s question papers, do it now.
  • Brush up your GK by getting your hands on some GK refresher books that are available online.

Here are some important tips for the exam day as well as the last week before the exam-

  1. Must have a solid hold of fundamentals; now is the time to revise just the basics with no more knowledge addition at this instant.
  2. Time management is essential for the exam and it could help in scoring more.
  3. Every single question do not need to be solved seeing that there is bad marking. Select everything from the topics you are best at and try solving it.
  4. Previous year papers ought to be checked to know what kind of questions appear and one particular mock test can be taken in the last day to see what may be the strategy that may help in the flow of solving.
  5. Evaluation question at first once you get it can help in recognising areas where questions that you are more powerful in and could end up being definitely solved by you may help and only the flow of solving ought to be decided.
  6. If you are stop at a spot just try moving forward and don’t waste a lot of time on any question.
  7. Speed and accuracy can only help in obtaining the examination clear and being needed the SSB.
  8. Mugging up issues doesn’t really help in such standard exams but if basics are clear you can win the battle easily.

Arihant publications books are quite useful for CDS. And CDS demands comprehensive study.
NCERTs, Lucent, Laxmikanth polity etc. are important.

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