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Figure 1. Main steps leading from the Kiss gene to the Kp(10) peptide. ORF, open reading frame; UTR, un-translated region; CDS, coding sequence; SP, signal peptide; Kp, mature kisspeptin. Predicted ORF sequence containing Kp(10) is represented as a red line. The intron and exon represented in blue have been observed in some mammalian Kiss1 genes including human Kiss1, pig Kiss1, and mouse Kiss1.
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Figure 2. Proposed origin of osteichthyan Kissr tetra-paralogons. The paralogous genes of each of the eight identified families delineate four paralogons in the spotted gar, coelacanth, and human genomes and a duplicated tetra-paralogon in the zebrafish genome. This suggests a common origin of the four Kissr before the two whole genome duplication rounds (1R and 2R) which occurred in the early vertebrate history. This also suggests no impact of the teleost-specific 3R on Kissr number in current teleosts. Chr, chromosome; LG, linkage group.
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Figure 3. Current status and proposed evolutionary history of Kissr genes (A) versus Kiss genes (B). (1) Vertebrates, (2) gnathostomes, (3) osteichthyans, (4) actinopterygians, (5) sarcopterygians, (6) teleosts, (7) tetrapods, (8) amniotes, (9) euteleosts, (10) diapsides, (11) mammals. The names of the current representative species of each phylum are given at the end of the final branches, together with the symbol of the Kiss and Kissr genes they possess. These hypotheses assume the presence of four Kiss and four Kissr paralogs in the vertebrate lineage resulting from the two rounds of vertebrate whole genome duplication. Multiple subsequent gene loss events are indicated in the various lineages.
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Figure 4. Sequence alignment of vertebrate Kp(10). At each position, identical amino-acids are shaded in dark gray and similar amino-acids in light gray. Newly identified sequences are underlined and unique sequences are marked by an asterisk.
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Figure 5. Conserved genomic synteny of osteichthyan Kiss. Genomic synteny maps comparing the orthologs of Kiss1
(A), Kiss2
(B), Kiss3
(C), Kiss4
(D), and their neighboring genes. Analyses were performed on the genomes of human (Homo sapiens), platypus (Ornithorhynchus anatinus), lizard (Anolis carolinensis), chicken (Gallus gallus), Xenopus
(Xenopus tropicalis), coelacanth (Latimeria chalumnae), spotted gar (Lepisosteus oculatus), zebrafish (Danio rerio), stickleback (Gasterosteus aculeatus), and European eel (Anguilla anguilla). This map was established using the PhyloView of Genomicus v67.01 web site, manual annotation of the European eel genome using CLC DNA Workbench 6 software and the gene annotation of the coelacanth and spotted gar genomic databases. Kiss genes are named according to our proposed nomenclature (Kiss1 to Kiss4). The other genes are named after their human orthologs according to the Human Genome Naming Consortium (HGNC). Orthologs of each gene are shown in the same color. The direction of arrows indicates the gene orientation, with the position of the gene (in 10−6 base pairs) indicated below. The full gene names and detailed genomic locations are given in Table S1 in Supplementary Material. Chr, chromosome; LG, linkage group; Gr, group; Sc, scaffold; Cg, contig.
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Figure 6. Proposed origin of osteichthyan Kiss tetra-paralogons. The paralogous genes of each of the 11 identified families delineate four paralogons in spotted gar, coelacanth, and human genomes and a duplicated tetra-paralogon in the zebrafish genome. This suggests a common origin of the three Kiss before the two whole genome duplication rounds (1R and 2R) which occurred in the early vertebrate history. This also suggests no impact of the teleost-specific 3R on Kiss number in current teleost species. Chr, chromosome; LG, linkage group.
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Figure A1. Prediction of two Kiss ORFs from the European eel genome. Nucleotide and deduced amino-acid sequences of the ORF encoding the European eel Kp1(10) (A) and Kp2(10) (B). Nucleotides (top) are numbered from 5′ to 3′. The amino-acid residues (bottom) are numbered beginning with the first amino-acid residue encoded by the ORF. The asterisk (*) indicates the stop codon. The predicted Kp(10) are underlined. The amino-acids of the C-terminal α-amidation and cleavage site are shaded in gray.
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Figure A2. Prediction of two Kiss ORFs from the spotted gar genome. Nucleotide and deduced amino-acid sequences of the ORF encoding the spotted gar Kp1(10) (A) and Kp2(10) (B). Nucleotides (top) are numbered from 5′ to 3′. The amino-acid residues (bottom) are numbered beginning with the first amino-acid residue encoded by the ORF. The asterisk (*) indicates the stop codon. The predicted Kp(10) are underlined. The amino-acids of the C-terminal α-amidation and cleavage site are shaded in gray.
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Figure A3. Prediction of three Kiss ORFs from the coelacanth genome. Nucleotide and deduced amino-acid sequences of the ORF encoding the coelacanth Kp1(10) (A), Kp2(10) (B), and Kp3(10) (C). Nucleotides (top) are numbered from 5′ to 3′. The amino-acid residues (bottom) are numbered beginning with the first amino-acid residue encoded by the ORF. The asterisk (*) indicates the stop codon. The predicted Kp(10) are underlined. The amino-acids of the C-terminal α-amidation and cleavage site are shaded in gray.
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Figure A4. Prediction of a third Kiss ORF from the elephant shark genome. Nucleotide and deduced amino-acid sequences of the ORF encoding the elephant shark Kp3(10). Nucleotides (top) are numbered from 5′ to 3′. The amino-acid residues (bottom) are numbered beginning with the first amino-acid residue encoded by the ORF. The asterisk (*) indicates the stop codon. The predicted Kp(10) is underlined. The amino-acids of the C-terminal α-amidation and cleavage site are shaded in gray.
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