Evaluation of Genetic Diversity of Golden Apple Snail, Pomacea Canaliculata (Lamarck), in the Philippines and China Through Dna Barcoding

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ABSTRACT
Genetics is a trend these days especially that, DNA barcoding has been developed. DNA barcoding is an important tool in categorizing the taxa of different species and it tells so much about the species’ traits, including genetic diversity. The Pomacea canaliculata was introduced in different parts of Asia and had been an invasive species and a pest in different ecosystems ever since the introduction. In understanding this species of snails, samples were collected, DNA’s were extracted, undergone PCR and electrophoresis, and was sequenced and analyzed. The analysis was qualitative In the Philippines while quantitative in China. In the Philippines, the cytochrome oxidase subunit 1 (COI) genes was used and compared among the species collected and when it was sequenced, it showed differences due to localized gap, mismatch and non-correspondence of bases. And in China, the diversity was analyzed by means of Nei’s gene diversity, Shannon’s information index, percentage of polymorphic bands (PPB) an AMOVA anlysis. Both the quantitative and qualitative showed that there was diversification within and among the populations of these snails.

INTRODUCTION
Genetics is the study of the genes, and the heredity and variation of individuals. Understanding the genome, which is the complete set of chromosomes or the entire genotype of an individual, is important because it helps in the taxonomy of species, especially nowadays wherein advancements in science needs more specific information, and that basing on morphological features is not enough. Life is specified by genomes which contain all the biological information which is encoded in its deoxyribonucleic acid (DNA) and divided into units or the genes. The genes are the blueprint for life because it is the particulate determiner of hereditary traits. Hence, DNA barcoding became a trend for scientists and researchers for the understanding of the different variations in the traits of different organisms.

The golden apple snails (Pomacea canaliculata) originated from the South America, Central America, the West Indies and the Southern USA (Pain 1972) and was spread in the past decades to the different parts of Southeast Asia, namely Philippines, China, Thailand, Cambodia, Hong Kong, Indonesia and Japan. The introduction of the P.canaliculata without prior studies caused damages to the different plants and it became an invasive species which resulted to becoming pests to humans and competitors to other local snails, example of which are those from the genus Pili. The P. canaliculata was observed to have different growth and reproduction in different parts of Asia, together with their external characteristics due to the different habitats and environmental conditions (Keawjam, 1986 and 1987), therefore there is the possibility to misidentify two sympatric species as one. On the other hand allopatric populations inhabiting different habitats may show ecomorphological variations and questionable species status and it was also suggested that the golden apple snails had high adaptability hence it was easier for them to form new populations (Dong et al. 2011).

The understanding of the genomes of different species is a trend for scientists these days but the information about the different mollusks is still limited. The basic information on the number of species and/or population is of help for conservation programs (Carvalho and Hauser, 1994) and for building appropriate management schemes. In contribution, the studies aims are to evaluate the genetic diversity of the golden apple snail population in Asia, namely, Philippines and China via molecularly characterizing the P.canaliculata and to find different ways of analyzing the gathered data from the sequenced DNA of the said species.

REVIEW OF RELATED LITERATURE
Genetic diversity (Reed 2005)
The significance of genetic diversity arose from two necessities: genetic diversity is required for populations to evolve in...
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