Insect Taxonomy—Basics to Barcoding 77
Cladoendesis—New Approach to
Phylogenetic Construction
The term cladoendesis was introduced by N. J.
Kluge in early twenty-first century, meaning
“branch coupling” that pays more attention on
the connection between apomorphies of each
taxon and characteristics of higher taxa, so that
the characters of all the taxa are, from the very
beginning, considered to be interrelated within
a certain hierarchy (Kluge 2012 ). It is a method
of phylogenetic analysis opposed to various ma-
trix methods. The phylogenetic trees are not built
each time as new ones but reconstructed based on
the previous results where each character of each
taxon is compared with its ancestral condition in
the ground plan of the higher taxon (Kluge 2012 ).
Cladoendesis enables understanding of nature
and evolution of metamorphosis in insects.
All the schools eventually yield phylogenetic
trees, a visual representation of the fact that spe-
cies are related by descent from a common ances-
tor. Depending upon the type of school used in
the construction, it may be called as phenograms
(arrived from phenetics) or cladograms (arrived
from cladistics).
Molecular biology has taken the systematics
towards a different turn. The convergence of un-
related in species under similar selection pressure
and divergence of related in species under differ-
ent selection pressure yields to surge toward mo-
lecular taxonomy as an additional tool in support
of traditional taxonomy in diagnostics. Recent
advances in molecular techniques have greatly
helped to resolve the controversial classification
schemes based either largely or entirely on mor-
phological attributes (Viraktamath 2003 ).
Molecular Systematics
Early attempts at molecular systematics were also
termed as chemotaxonomy that made use of pro-
teins, enzymes, carbohydrates, and other mole-
cules that were separated and characterized using
techniques such as chromatography. These have
been replaced in recent times largely by DNA se-
quencing, which produces the exact sequences of
nucleotides or bases in either DNA or RNA seg-
ments extracted using different techniques.
The theoretical framework for molecular sys-
tematics was laid in 1960s which plunged into
DNA–DNA hybridization during 1974–1986.
The advantage claimed for using hybridiza-
tion rather than gene sequencing was that it was
based on the entire genotype, rather than on par-
ticular sections of DNA. Another application in
molecular phylogeny is DNA barcoding, wherein
the species of an individual organism is identi-
fied using small sections of mitochondrial DNA
(mtDNA) or chloroplast DNA that demarcates
species as lineages (Hebert et al. 2003 ).Insect Mitochondrial DNQA and DNA
Barcoding
Mitochondrial genes are often chosen for evolu-
tionary studies as they have a number of positive
characteristics like: (i) maternal inheritance with
little or no recombination (ii) general conserva-
tion of gene order and composition (iii) small
size compared with the nuclear DNA and (iv) the
lack of introns (Gissi et al. 2008 ). mtDNA have
proven to be informative in the study of species
diversity and evolutionary processes because it is
easy to isolate and contains conserved sequences
that make it possible to use as universal primers
(Otranto and Stewens 2002 ; Xie et al. 2006 ).
Extensive studies in the mtDNA of Dro-
sophila species showed that the same genes are
present in both mammals and invertebrates; how-
ever, their arrangements may differ (Clary and
Wolstenholme 1985 ; Crozier and Crozier 1993 ).
The protein coding genes are the most frequently
sequenced mitochondrial genes for evolutionary
studies and phylogenetic analysis. Protein coding
genes commonly analyzed include; COI, COII,
16S, and 12S. In particular, the COI gene has
been widely sequenced. Yet, the specific region
chosen has varied from study to study (Lunt et al.
1996 ; Caterino et al. 2000 ). The first subunit of
mtDNA CO gene, corresponding to nucleotides
1490–2198 of the D. yakuba sequence, has been
identified as an area of interest for “DNA bar-
coding” (Hebert et al. 2003 ). This region has a