Publication: Karyotype evolution and geographical distribution of the Thai‐medaka, Oryzias minutillus, in Thailand
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Issued Date
1992
Resource Type
File Type
application/pdf
ISSN
221112
Other identifier(s)
2-s2.0-84986440287
Rights Holder(s)
Scopus
Bibliographic Citation
Journal of Fish Biology. Vol 41, No.3 (1992), p.489-497
Suggested Citation
Magtoon W., Nadee N., Higsdhitani T., Takata K., Uwa H. Karyotype evolution and geographical distribution of the Thai‐medaka, Oryzias minutillus, in Thailand. Journal of Fish Biology. Vol 41, No.3 (1992), p.489-497. doi:10.1111/j.1095-8649.1992.tb02676.x Retrieved from: https://hdl.handle.net/20.500.14740/7488
Author(s)
Abstract
The karyotype of Oryzias minutillus was examined with specimens collected from 18 localities in Thailand. Specimens from the south and the northeast had 2n = 42 acrocentric chromosomes; the arm number (NF) was 42 and NORs‐chromosomes were acrocentric type (2n = 42, NF = 42, NORs‐A). Specimens from the central and the north were characteristic by having 8‐12 large metacentric chromosomes (LM‐chromosomes). They had 2n = 28–34 chromosomes, and shared the same NF and NORs‐chromosomes of submetacentric type (2n = 34‐28, NF = 44, NORs‐SM). Specimens from the southeast had 2n = 42 or 40 chromosomes. Their karyotypes had the same NF and NORs‐chromosomes as those from the central and the north (2n = 40–42, NF = 44, NORs‐SM), though they had no, or only one pair of, LM‐chromosomes. The karyotype with 42 acrocentric chromosomes seems to be basic for O. minutillus, and consequently those with NORs‐SM and LM‐chromosomes seem to be caused through pericentric inversion and centric fusion, respectively. We confirmed that the karyotype evolution had occurred in drainage areas of the Mae Nam Chao Phraya and collaterals (the central, north and southeast). On the other hand, the basic karyotype was preserved allopatrically in the peninsula (the south) and the basin of the Mae Nam Mun, a tributary of the Mekong (the northeast). Copyright © 1992, Wiley Blackwell. All rights reserved