The Intertidal Harpacticoid Copepod Tigriopus japonicus (Crustacea: Copepoda) β-actin Gene: Cloning, Sequence and Intraspecies Variation

Abstract

The Tigriopus japonicus β-actin genes were amplified from genomic DNA by polymerase chain reaction (PCR) and cloned into pCRII vector. Several clones of the T. japonicus β-actin gene spanned 1662–1676 bp with gains or losses of some bases in intron 3 or 4 but they consisted generally of 5 exons and 4 introns with very high homology, implying polymorphism of this gene. The exon and intron boundaries were matched with the GT/AG rule. The T. japonicus β-actin gene showed high homology to the fish (Rivulus marmoratus) and human genes, 99.2 and 98.4%, respectively at the amino acid sequence level. The phylogenetic implications inferred from the T. japoncius β-actin gene are discussed.

• β-Actin gene
• Cloning
• Variation