OJBTM
Online Journal of Bioinformatics
Volume 11 (1): 59-71, 2010.
In silico
identification of functions enduring horizontal gene transfer in archaea.
Tamanna A1*, Nandi T1
1 Department of
Biotechnology, Jaypee Institute of Information
Technology University, Noida (UP) 201307, India.
ABSTRACT
Tamanna A1*,
Nandi T., In silico identification of functions
enduring horizontal gene transfer in archaea: a comparative approach. Onl J Bioinform., 11 (1): 59-71, 2010. A
major route of genomic evolution in bacteria is the acquisition of new genes
from often very distantly related individuals through horizontal gene transfer
(HGT). Archaea sustaining extremophilic life, evolve
by undergoing HGT to adapt to extreme conditions. With the availability of
increasing amounts of genomic sequences, it is becoming evident that genomes
experience horizontal transfer and integrate genetic information. However, the
knowledge on the type of biological functions that is associated with such HGT
remains scarce. Genome scale investigation of this issue will advance the
understanding of functional classes of the genes that are involved in HGT. In
this study, we have applied a comparative genomics approach to analyze 16
archaeal genomes that have been completely sequenced and assigned each gene
with a HGT score according to w8 algorithm proposed by Tsirigos
et al., 2005. We observed that the average fraction of proteins per
proteome with ≥ 90% HGT score is 6.7%. The average fraction of proteins
with significant sequence and function homology is 73.5% and 26.5%,
respectively. Based on the comparative analysis at the sequence and function
level, we have short-listed 54 unique protein functions that are more likely to
undergo the phenomenon of HGT across 16 archaea. Cluster of Orthologous Groups
(COGs) classification of the identified 54 protein functions revealed that the
classes for energy production & conversion (C) and amino acid transporter
& metabolism (E) are predominant. We have investigated the association of
the biological function of genes and their preferences towards the phenomenon
of horizontal gene transfer. This methodology can also be applied to the
identification of biological functions associated with HGT in bacterial domain.
Keywords:
Horizontal gene
transfer (HGT).
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