Fig. 8

Analysis of centromeres of channel catfish and blue catfish. A Southern blot analysis of channel catfish genomic DNA digested with Xba I restriction endonuclease (adopted from [25]), showing tandem structure as a ladder was produced with incremental amounts of Xba I enzyme (Lanes 1–6). The molecular weight standards are indicated on the right margin. B Fluorescence in situ hybridization of Xba elements labeled with digoxigenin and detected with FITC-labeled anti-digoxigenin on channel catfish metaphase chromosomes (2n = 58), adopted from Quiniou et al. [26]. C Comparison of relative centromeric locations and sizes of channel catfish (orange) and blue catfish (blue) chromosome scaffolds. Note that the relative size of centromeres was amplified by × 2 to clearly show the difference between channel catfish and blue catfish. D Quantitative real-time PCR using Xba element-specific primers. The Ct values of 8.96 10.43, and 24.63 were observed for channel catfish Xba (orange), blue catfish Xba (blue), and a single-copy microsatellite marker (gray), respectively. E Divergence rates of Xba elements of channel catfish (orange) and blue catfish (blue) as denoted by the Xba elements as a percentage of total genomic repeats versus substitution rate (% substitution per site)