Status : Verified
Personal Name Halili, Jordan Ferdin A.
Resource Title DNA barcoding and molecular phylogeny of the Philippine Helicarionidae (Pulmonata: Stylommatophora)
Date Issued June 2016
Abstract The phylogeny of the terrestrial snail family Helicarionidae is poorly understood. This study aimed to barcode helicarionids found in the Philippines and perform a phylogenetic analysis to infer relationships of the group. A total of nine species, namely Hemiglypta moussoni (n=2), Lepidotrichia luteofasciata (n=1), Nipponochlamys semisericata (n=1), Ryssota uranus (n=6), R. sagittifera batanica (n=5), R. zeus (n=6), and the Philippine endemic Hemiglypta semperi (n=3), R. otaheitana (n=9), and R. lamarckiana (n=4), were barcoded using the standard marker cytochrome c oxidase I (CO1) gene. A further two genera, Hemiglypta sp. (n=3) and Lepidotrichia sp. (n=3), were also included. Helicarionid individuals were obtained from various sites in the Philippines (Aurora, Batanes, Bicol, Laguna, Leyte, Marinduque, Mindoro, Romblon and the Polillo Group of Islands). Highest sequence divergence was found within the family level (mean K2P distance=18.87%) and least within the species level (mean K2P distance=1.64%). Overlap was noted between interspecific and intraspecific variations. Neighbor-joining tree based on the Kimura-2- parameter model of DNA substitution revealed most species to be monophyletic with the exception of R. otaheitana; the species is therefore tagged for taxonomic re-evaluation. The phylogenetic analysis of Philippine helicarionids was done using the mitochondrial genes, CO1 (548 bp) and 16S rRNA (374 bp), and the nuclear rRNA gene cluster (1585 bp). Trees were constructed for each gene using the model-based methods Neighbor-Joining, Maximum Likelihood, and Bayesian Interference Analysis and the non-model based Maximum Parsimony and were rooted to the urocyclid Sheldonia as the outgroup. All of the trees showed clustering of the Philippine samples into one big clade with equivocal support (<50%). Three major subclades were consistently observed, namely, the Ryssota clade, Hemiglypta clade and the Lepidotrichia clade, with high bootstrap supports. A phylogenetic signal was detected for all the genes used using the g1 test. The use of other characters such as shell morphology, reproductive anatomy and ecology complemented by such molecular studies would be helpful to better understand the phylogeny of this group.
Degree Course Master of Science in Biology
Language English
Keyword Helicarionidae, CO1, 16S, rRNA gene cluster, DNA barcoding, molecular phylogeny, Philippines
Material Type Thesis/Dissertation
Preliminary Pages
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