Fig 1.
The nuclear DNA content of L. morii.
Nuclei from each tissue were isolated from the same three individuals, propidium iodide-stained and analyzed by flow cytometry. Chicken erythrocytes (2C = 2.50 pg DNA) and zebrafish erythrocytes (2C = 3.223 pg DNA) served as independent internal reference standards. (A, B) Sperm nuclear DNA content with chicken erythrocytes (A) and zebrafish erythrocytes (B). An asterisk marks a peak corresponding to spermatogonia or sperm doublets. (C, D) Erythrocyte nuclear DNA content with chicken erythrocytes (C) and zebrafish erythrocytes (D). The horizontal axis represents the fluorescence value of cells, which is directly proportional to DNA content within the same sample. The vertical axis represents the number of single cells detected.
Fig 2.
Karyotype analysis of L. morii.
Colchicine was injected into adult L. morii to arrest cell division at metaphase. The gills and intestine were separated, Giemsa stained and observed through high magnification microscopy. The gill (A) and intestine (B) chromosome numbers were 2n = 132 and 2n = 131, respectively. Two more individuals were tested, and the chromosome numbers ranged from 130 to 132.
Fig 3.
Amplification of 96 pairs of EcoRI-MseI fragments.
According to the number, clarity and distribution range of the bands, we screened 7 primer combinations (with an asterisk) to analyze polymorphism: E01/M12 (EcoRI+AAC/MseI+CCT), E05/M04 (EcoRI+AGA/MseI+CAT), E02/M01 (EcoRI+AAC/MseI+CAA), E06/M01 (EcoRI+AGT/MseI+CAA), E03/M06 (EcoRI+ACA/MseI+CCT), E07/M01 (EcoRI+ATC/MseI+CAA), E04/M01 (EcoRI+ACT/MseI+CAA). The primer pairs are listed in Table 2. The molecular weight size range of the fingerprints is from 20 to 500 nucleotides.
Table 1.
AFLP polymorphism rates for L. morii.
Table 2.
Adapters and primers used in AFLP analysis.
Table 3.
SNPs in five selected introns of L. morii and B. belcheri.
Fig 4.
Structure of the L. morii mitochondrial noncoding region (A) and a phylogenetic tree based on this region (B).
The tree was constructed using the maximum likelihood method with the Tamura—Nei substitution model. The mitochondrial noncoding region sequences of P. marinus, Lethenteron reissneri, Lethenteron japonicum, Lampetra fluviatilis, Lampetra aepyptera, Lampetra appendix, Ichthyomyzon unicuspis, Ichthyomyzon fossor, and Geotria australis were obtained from the NCBI database with accession numbers NC_001626.1, KC353466.1, KC353468.1, Y18683.1, NC_026917.1, NC_025583.1, NC_025553.1, NC_025552.1, and NC_029404.1, respectively.
Table 4.
Primers used to amplify genomic and mitochondrial fragments.