Phylogenetic analysis of cox i gene in identification of spiders

Abstract

Morphological diversity refers to diversity of species at the genetic or molecular level. In order to study the diversity at the genetic level the taxonomic method DNA barcoding is used. The most commonly used barcode region for animals and some protists is found in mitochondrial DNA (Mt-DNA) i.e. a portion of the cytochrome oxidase I (Mt-Cox I) gene. The cox gene has a frequency of faster mutation rate and are highly conserved among the species hence Mt-Cox I sequence was used for the practical method of species identification. In the present study, the most dominant female spiders collected were Argiope aemula, Nesticodes rufipes, Oxyopes lineatype, Leucauge decorata, Nephila kuchli, and Nephila philipis. These spiders were preserved in 70% ethanol and DNA was extracted. The amplification of the gene and PCR analysis was done by treating forward and reverse primers. The Cox I gene was sequenced for BLAST sequence similarity search. The phylogenetic analysis revealed the relationship between molecular and morphological taxonomy. The six species with different families have raised from a common ancestor. At each branch point lies the most recent common ancestor of all the groups descended from that branch point. The four descendents N. rufipes, N. kuchli, N. philipis and O. lineatype raised from one common ancestor, but O. lineatype emerged as an out group species from the others. Argiope aemula and Laucauge decorata raised from the other common ancestor, indicating the homology sharing.