Molecular Basis of Transferrin Polymorphism in Goldfish (Carassius auratus)

Abstract

Transferrin (TF) polymorphism was investigated in a color variety of goldfish (Carassius auratus), and its molecular basis analyzed. Three TF variants (A 1 , A 2 and B 1 ) were identified from an inbred strain of the goldfish, of which A 1 and B 1 displayed a large electrophoretic difference on both native and SDS-PAGE gels. The TF cDNAs corresponding to variants A 1 and B 1 were cloned and sequenced from A 1 A 1 , A 1 B 1 and B 1 B 1 individuals, and their deduced amino acid sequences were analyzed. Substantial amino acid variation occurred between variants A 1 and B 1 , with significant differences in peptide length, theoretical molecular weight (Mw) and isoelectric point (pI). No potential glycosylation sites were observed in the two amino acid sequences, which excluded the possibility that carbohydrate difference might cause electrophoretic variation among the TF variants. Further analysis suggested that the distinct electrophoretic mobility of the two variants A 1 and B 1 by SDS-PAGE resulted from their Mw difference, while the difference by the native PAGE could be explained by their pI variation. Furthermore, genomic DNA fragments containing the transferrin alleles were amplified and subjected to RFLP analysis in A 1 A 1 , A 1 B 1 and B 1 B 1 individuals. The data revealed characteristic banding patterns for each TF genotype, and demonstrated that the TF alleles A 1 and B 1 could be used as a co-dominant marker system. The initial work relating to the goldfish TF variants will benefit the understanding of the evolutionary and functional significance of TF polymorphism in fish.

Transferrin gene polymorphisms and population genetic studies of Atlantic cod (Gadus morhua)

“…This is in line with what has been reported about the existence of sequence variation [1], whereby 113 substitutions and 77 amino acid replacements were detected between coding sequences of the goldfish transferrin alleles A1 and B13. In studying the effects of natural selection on patterns of DNA sequence [19], variation within and among four populations of chinook salmon was described.…”

“…A number of transferrin variants have been identified and characterized in many different fish species that include, but not limited to the following, goldfish Carassius auratus (C. auratus) [1], crucian carp C. auratus [2], scad Trachurus trachurus L. [3], coho salmon Oncorhynchus kisutch [4], haddock Melanogrammus aeglefinus L. [5], Channa punctatus [6], European common carp Cyprinus carpio carpio L. [7], Nile tilapia Orechromis niloticus [8], and carp [9].…”

Genetic basis and breeding application of clonal diversity and dual reproduction modes in polyploid Carassius auratus gibelio

“…In China, various clones have been discriminated in natural populations by morphological phenotypes [40], allozyme markers [41], tissue graft analysis [42], serum transferrin phenotypes [43], RAPD (random amplification polymorphism of DNA) and SCAR markers [44,45], microsatellite markers [46], transferrin allele polymorphism [47][48][49], and mtDNA control region sequences [49]. Significantly, some clone-specific molecular markers have been isolated, and used to select the better strains for aquaculture cultivation of gibel carp [46,49].…”

“…Based on the discovery of dual reproduction modes of gynogenesis and sexuality and molecular marker identification in polyploid fish [43][44][45][46][47][48][49], we performed numerous mating experiments between 2 different clones [25], and found a few of preponderant individuals from the sexual mating progeny between clone D and clone A. The individuals were propagated by 6 successive generations of gynogenesis with Xingguo red common carp (Cyprinus carpio) sperm stimulation, and several hundred millions of individuals were produced in hatcheries and used for aquaculture practice.…”

Identification of One Intron Loss and Phylogenetic Evolution of Dfak Gene in the Drosophila melanogaster Species Group

“…One or two ll of the cDNA was used for amplification in a 50-ll reaction mixture containing 1· buffer, 200 lM dNTP, 0.5 lM of Fak01 primer and Fak02 primer, and 2 units of Taq DNA polymerase (Biostar). The cycling profile, cloning and sequencing analysis were performed as described previously Yang, Zhou & Gui, 2004). Act5C cDNA was amplified as a control with primers of act5c-1 (GTGAC-GAAGAAGTTGCTGCTC) and act5c-2 (AT-CTGCTGGAAGGTGGACGAC) to produce a 1063 bp fragment as expected (Parsch et al, 2001).…”