What is Metagenomics?

Origin of Metagenomics

Metagenomics does not depend on the process of cultivation; it allows the study of the large majority of microorganisms that cannot be cultured.

In the 1980s, Carl Woese found that the 16S ribosomal ribonucleic acid (rRNA) gene could determine the phylogeny (evolutionary relationship) of prokaryotes (Citation 1).

All organisms contained a homolog, related form of this gene; this tool allowed Woese to categorize the three domains of life: Eukaryote (multicellular), Archaea and Bacteria(singe celled).

 

Image of an 16S rRNA three way
function with the ribosomal protein S8.

Microbial Communities undergo 16S rRNA gene analysis

Norman Pace proved that 16S rRNA genes could be isolated and cultivated and extended from the environment by using the polymerase chain reaction (PCR); PCR produces many copies of each gene for cloning and sequencing. Pace designed primers to amplified and cloned genes that were identical in all organisms. Afterward he determined the complete nucleotide sequence of each gene. Pace and others soon began to construct date of the 16S rRNA from diverse environments such as sediment, seawater, and surfaces of plants and animals (Citation 1).

Analysis of 16S rRNA genes found that most species that underwent culture-independent analysis were new; revealing that there were thousands of species that have yet still be discovered. Yet PCR analysis can amplify only the specified genes from organisms, leaving the rest of the genome unaccounted. Microbiologists need another approach to study the genetics and physiology; this called for the new field of metagenomics. (Citation 1).

Construction of a metagenomic library through DNA extraction from an environment sample (containing a diverse mixture of organisms), followed by cloning the DNA in fragments into a cultivable bacterium, and finally analyzing the cloned DNA or the metagenomic library is the process of metagenomics.

The Father of Microbiology
 

     I
n the Greek language, "meta" means "transcendent" Metagenomics transcends pass traditional and classical approaches to microbiology (Citation 2).

     This  field provides more  perspective on the microbes found within the environment. Anton van Leeuwenhoek (also considered as “the Father of Microbiology”) made vital discoveries and contributions that lead to the establishment of microbiology (Citation 3). He was the first to describe and observe single-celled organisms or microorganisms, bacteria, muscle fibers, and blood flow in capillaries (Citation 3).

     In 1674, van Leeuwenhoek collected a sample of pond scum, discovered Spirogyra, and flagellated protozoa. This event in turn gave rise to fields of microbiology, protistology, and phycology (Citation 4).

 

Automated pipette taking samples from vials for DNA (deoxyribonucleic acid) analysis.

 

What is Metagenomics?
 

    Metagenomics allow scientists to analyze the genetic material of entire microbial communities. By combining genetic and molecular biology, this field identifies and characterizes genetic material from  environmental samples (Citation 7).

     Since many microbes cannot be isolated and cloned  through traditional methods, our knowledge of these microbes' species has come to an abrupt halt. Metagenomics bypasses traditional methods.

     This new innovating field allows a compilation of data that could have not been acquired through traditional methods.

     Metagenomics analyzes the genetic material of entire microbial communities, which allow scientists to discover the influence of genes upon each other.

Genomic analysis derived from traditional methods are limited since those microorganisms have be first cultivated within a laboratory.


A
lthough the study of microbiology has existed for many centuries, Metagenomics is a new field. In the year 1998, Handelsmen and his colleges  first used the term "metagenome" unaware that they were opening a door leading to new discoveries and technological advances (Citation 5).  

 

Why Metagenomics?

T
his field differs from traditional gene sequencing and provides a process to acquiring an abundance of  information. Since many microbes cannot be cultivated within a laboratory and therefore cannot be studied using tools of classical microbiology, metagenomics is the key


 Traditional gene sequencing  limitations include:
  • Limited gene analysis- scientists could only clone cultivatable genes, merely less than one percent of the millions of microbes on Earth were cultivable
  • No study of microbial biodiversity- the cultivation technique includes no variation of the microbes in its natural habitat
  • This process only provides historical and evolutionary development information of the specific gene, not how genes could affect one another.

 

A researcher using a magnifying glass to study a DNA sequence produced using gel electrophoresis techniques.

 


 

 "Metagenomics gives scientists access to millions of microbes that have not previously been studied" (Citation 8)

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Want More Information About Genomics?


This page explains genomic, DNA, metagenomics, and omics. It also depicts genome expression in both plants and bacterial cells, a chart that depicts the three-letter mRNA codons including the particular amino acids they specify. Lastly, a time-line of the selected points that changed and developed genomic history (Citation 35).

 

Home  //  Microbes  //  What is Metagenomics  //  Process  //  Challenges  //  Studies  //  Impact  //  Innovators //  References 

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