Comparative study of four Mystus species (Bagridae, Siluriformes) from Thailand: insights into their karyotypic diversity

Abstract

Karyotypes of four catfishes of the genus Mystus Scopoli, 1777 (family Bagridae), M. atrifasciatus Fowler, 1937, M. mysticetus Roberts, 1992, M. singaringan (Bleeker, 1846) and M. wolffii (Bleeker, 1851), were analysed by conventional and Ag-NOR banding as well as fluorescence in situ hybridization (FISH) techniques. Microsatellite d(GC)15, d(CAA)10, d(CAT)10 and d(GAA)10 repeat probes were applied in FISH. The obtained data revealed that the four studied species have different chromosome complements. The diploid chromosome numbers (2n) and the fundamental numbers (NF) range between 52 and 102, 54 and 104, 56 and 98, or 58 and 108 in M. mysticetus, M. atrifasciatus, M. singaringan or M. wolffii, respectively. Karyotype formulae of M. mysticetus, M. atrifasciatus, M. singaringan and M. wolffii are 24m+26sm+4a, 26m+24sm+2a, 24m+18sm+14a and 30m+22sm+6a, respectively. A single pair of NORs was identified adjacent to the telomeres of the short arm of chromosome pairs 3 (metacentric) in M. atrifasciatus, 20 (submetacentric) in M. mysticetus, 15 (submetacentric) in M. singaringan, and 5 (metacentric) in M. wolffii. The d(GC)15, d(CAA)10, d(CAT)10 and d(GAA)10 repeats were abundantly distributed in species-specific patterns. Overall, we present a comparison of cytogenetic and molecular cytogenetic patterns of four species from genus Mystus providing insights into their karyotype diversity in the genus.

Comparative cytogenetic analysis of fishes in the genus Trichopodus (Osphronemidae) in Thailand

“…The NORs are used as markers to detect species-specific character and indicate intra-and interspecies chromosomal polymorphism in many groups of fishes (Cioffi et at. 2015;Phimphan et al 2015;Sarasan et al 2018;Kasiroek et al 2017;Yeesin et al 2021). The Ag-NOR positions were shown on the single chromosome pair.…”

Are scattered microsatellites weak chromosomal markers? Guided mapping reveals new insights into Trachelyopterus (Siluriformes: Auchenipteridae) diversity

“…One of the most challenging problems in expanding the use of microsatellites in fish cytogenetics is the scattered distribution pattern (e.g., [34][35][36], Table 1), because this type of array exhibit apparently random signals on the chromosomes. As a consequence, in most species without B or sex chromosomes, it hampers the description of useful distribution patterns to discuss evolutionary aspects as well as the comparison between karyotypes, often leading to oversimplified interpretations that simply label it as widely distributed or scattered.…”