Abstract
Anguilla eels are divided into temperate and tropical eels, based on their major distributions. The present study collected two temperate eels, Anguilla japonica and Anguilla anguilla, and two tropical eels, Anguilla marmorata and Anguilla bicolor pacifica, to examine two questions: do temperate and tropical Anguilla eels have different genetic polymorphic patterns?; and do temperate Anguilla japonica and Anguilla anguilla have a closer relationship to each other than to tropical eels? In total, 274 sequences were cloned and sequenced from six conserved microsatellite loci to examine polymorphic patterns of these four catadromous eels. Different mutational events, including substitutions, and repeat-unit deletions and insertions, appeared in major regions, while different point mutations were observed in flanking regions. The results implied that parallel patterns of microsatellite sequences occurred within both tropical and temperate freshwater eels. Consensus flanking sequences of six homologous loci from each of the four species were constructed. Genetic distances ranged from 0.044 (Anguilla bicolor pacifica vs. Anguilla marmorata) to 0.061 (Anguilla marmorata vs. Anguilla anguilla). The tree topology suggests the hypothesis of Anguilla japonica and Anguilla anguilla being a sister group must be rejected.
Highlights
Freshwater eels of the genus Anguilla consist of 16 species and three subspecies [1] that are globally distributed in temperate, tropical, and subtropical areas
The tropical Anguilla marmorata is very common in the Indo-Pacific Ocean with a more-extensive distribution than temperate freshwater eels [3,4]
Changes in repeat numbers of major regions, substitutions in entire sequences, and indels in flanking regions, are principle reasons resulting in polymorphisms within microsatellite loci
Summary
Freshwater eels of the genus Anguilla consist of 16 species and three subspecies [1] that are globally distributed in temperate, tropical, and subtropical areas. The tropical Anguilla marmorata is very common in the Indo-Pacific Ocean with a more-extensive distribution than temperate freshwater eels [3,4]. Because of high polymorphism in the number of repeats, microsatellites are widely used as markers for studying genetic mapping, population structures, kinship, evolutionary genetics, and genetic diseases [11,12,13,14,15,16] In addition to those advantages, some loci can be well resolved to analyze high-level systematics by their flanking sequences. We examined 274 allelic sequences from six microsatellite loci to infer the mutation mechanisms of these loci among four Anguilla eels and explored the interspecific genealogy using consensus sequences of the flanking regions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
