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Vol. 53, 2014
Morphological and molecular differentiation of genus Corbicula suggests that two species
are sympatrically distributed in Datong Lake in the Central Yangtze
River Basin
Gui-Ping
Wang1, Ting Zhang2, Jian Zhang1,
De-Liang Li1* and Tiao-Yi Xiao1
1College
of Animal Science and Technology, Hunan Agricultural University,
Changsha 410128, China
2Centre for Environment and Water Resources, College
of Chemistry and Chemical Engineering, Central South University,
Changsha 410083, China
Abstract
Background: White and purple color
morphs of Corbicula have been identified all over the world. Previous
studies suggested that the distinct difference of inner shell color,
especially for sympatric individuals, derived mainly from their
different genetic constitutions, not just environmental conditions. Two
color morphs of Corbicula
sympatric in Datong Lake were compared by both morphometric methods
(shell length, shell height, and shell width) and genetic analysis
(based on the mitochondrial cytochrome c oxidase subunit I gene COI-mtCOI) to explore their
taxonomic relationship.
Results: Morphological analysis showed that there
were no significant differences in the values of SH/SL, SW/SL, and
SW/SH (P > 0.05) between
the two color morphs. Meanwhile, there were no significant differences
in measurable parameters among the four mitochondrial COI haplotypes
(DT-1, DT-7, DT-19, and DT-31) (P > 0.05). The sequences of four
haplotypes (DT-1, DT-7, DT-19, and DT-31) were identical to FW1, FW5,
FW4, and FW3, respectively. Restriction fragment length polymorphism
(RFLP) analysis showed that only the sequences of haplotype DT-7 could
be digested by the restriction enzyme SacI into two fragments with
200/500 bp. Haplotype DT-31 was found only in one individual (white
morph), while each of the other three haplotypes shared with both two
color morphs. Phylogenetic analysis demonstrated that the four
haplotypes were subdivided into two divergent clades among freshwater
clades, and haplotype DT-7 was a divergent sister taxon to the other
three.
Conclusions: The results indicated
that there were no distinct differences on morphological measures
between the two color morphs, and each color morph shared with all four
mitochondrial COI haplotypes. Two species (DT-7 referred as Corbicula
fluminea and DT-1, DT-19, and DT-31 as Corbicula leana) might coexisted
in the Datong Lake. Therefore, a comprehensive study combining nuclear
and mitochondrial data along with biological information should be
performed to confirm this assumption.
Key words: Corbicula; Mitochondrial DNA COI;
Phylogeny; Taxonomy.
*Correspondence: E-mail: lideliang80@aliyun.com
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