ISSN (Print): 2328-3777, ISSN (Online): 2328-3785, ISSN (CD-ROM): 2328-3793 American International Journal of Research in Formal, Applied & Natural Sciences AIJRFANS 14-205; © 2014, AIJRFANS All Rights Reserved Page 1 AIJRFANS is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research) Available online at http://www.iasir.net Subspecies identification in aphids (Homoptera: Aphididae) by application of partial sequence of cytochrome c oxidase subunit I (COI) gene: a view on the potential of method Nina V. Voronova Zoology Department of Belarusian State University, Minsk, Belarus I. INTRODUCTION Today the species problem remains one of the most fundamental biological problems as well as one extremely difficult to solve [1] . Debates surrounding the concept of a species concept have been going on for decades [2–6] . Ignoring the philosophical aspect of this problem, the most important question of the discussion is – if the living world is really discrete, on which level of the taxonomic system and by which criterion can we draw a line between taxonomic units so that their distinction and individuality are not in doubt [7-9] ? The species problem can be observed most clearly in evolutionarily young groups of animals where adaptive radiation of low level taxa was particular wide. The origination of a generous amount of species, subspecies, races and other forms in an evolutionarily short time have led to an abundance of difficult to distinguish taxa. Aphids (Homoptera: Aphididae) is just such a group. There is a large number of closed related species and subspecies and, perhaps, ecological races which only differ in their biology or host-adaptation among the aphids, but the evolutionary significance of such features are not unquestionable. The major ecological and morphological plasticity of aphids which had been repeatedly demonstrated in experiments [10-11] introduces additional complexity into construction of the phylogenetic system of this large group of animals. Nevertheless, it is impossible to disregard the questions of the taxonomic status of the closed related forms, because such forms of aphids may vary considerably in their harmfulness. Determination of the significance of each aphid species and subspecies as a crop pest is the main factor that forces scientists to search for new methods to detect morphologically similar groups. Another reason for researching the problem of the subspecies detection in aphids is the importance of obtaining knowledge about every evolutionary event in the group, including (or most importantly) the ones which belongs to the micro evolutionary level. Studying the micro evolutionary events allows us both to discover their mechanisms and to identify the main evolutionary trends in a group of phytophagous carrying such an importance for food production and plant ecology [12-13] . Cytochrome c oxidase subunit I gene (COI) is a mitochondrion gene of eukaryotes which was selected as the most effective molecular marker for species identification [14] . A 500–700-bp region at the 5' end of the COI gene forms the primary barcode sequence for members of the animal kingdom [15-16] . In our work we aimed to estimate whether the usage of COI partial sequences as a single molecular marker allows manifesting of morphologically indistinguishable subspecies in aphids. II. MATERIALS AND METODS Specimens and DNA extraction Specimens of aphids were collected in 2008–2010 from Russia and Belarus. We analyzed COI sequences from aphids of 17 species and subspecies belonging to 4 genera and 2 tribes within Aphididae (Table 1). Abstract: The family Aphididae is one of the most important for crop production group of phytophagous. In such groups, in which certain forms can noticeably vary in their host-specify and harmfulness, correct species and subspecies identification has great significance. Aphids (Homoptera: Aphididae) is known their high ecological plasticity and simultaneously this family includes a lot of closely related species, morphologically similar subspecies and other forms which morphology-based identification cannot be single-valued. Mitochondrial COI sequences are provided for not only species but subspecies identification of aphids from Europe. Fragments about 540-bp were analyzed. Most of the studied subspecies (76.92 percent) had distinct COI sequences. The rate of nucleotide substitutions on 5'-end of the COI gene varied from two to seven per length (0.37–1.30 %). Difference between subspecies reached the level typical for closed related species, and showed no individual variability or geographic affinity. Based on these results, we conclude that COI sequences can provide an effective tool for identifying aphid subspecies in such applications as pest management, monitoring and plant quarantine. Keywords: aphids • subspecies identification • DNA barcoding • COI • molecular taxonomy