Biology Reference
In-Depth Information
C
HAPTER
1
C
HAPTER
I. TAXONOMY
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II. PHYLOGENY
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1) 16S rRNA gene
2) Molecular techniques based on 16S rRNA gene
3) 16S rRNA gene sequencing in cyanobacteria
4) Diversity of cyanobacteria determined on the basis of molecular markers
5) The species concept in bacteria and cyanobacteria
III. EVOLUTION OF BACTERIA AND CYANOBACTERIA
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The root of the TOL
IV. THE OTHER SIDE OF THE COIN
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I. TAXONOMY
A classifi cation provides a platform to identify a particular organism to the level of species. The art
of classifi cation is known as taxonomy and phylogeny helps to draw evolutionary relationships
between the organisms classifi ed. So a phylogenetic system of classifi cation serves a better purpose
for classifi cation as well as inferring evolutionary relationships. The earliest taxonomic treatises
considered cyanobacteria as an algal group under the general name blue-green algae (Thuret,
1875; Bornet and Flahault, 1888; Gomont, 1892). Traditionally thus, the blue-green algae have been
classifi ed along with eukaryotic algae under the International Code of Botanical Nomenclature
(ICBN). As per rules of ICBN, a type species has to be deposited in a recognized Herbarium either
in a dried state or fi xed algal material. Due to the limitation in the availability of pure culture
strains and the paucity of information on their biochemical and genetic features, the earlier workers
depended mostly on morphological characteristics. Due to the absence of membrane-bound cell
