Further survey of chromosomal polymorphisms in the freshwater planarian Polycelis auriculata |
| |
Authors: | Wataru Teshirogi Fumio Ni-imura Sachiko Ishida |
| |
Affiliation: | (1) Department of Biology, Faculty of Science, Hirosaki University, 036 Hirosaki, Japan;(2) Laboratory of Biology, Nagano Women's Junior College, 380 Nagano, Japan |
| |
Abstract: | Although the chromosomal number of Polycelis (Seidlia) auriculata Ijima et Kaburaki is basically 2n = 6, this species shows remarkable chromosomal polymorphisms in different populations. Among worms collected at 30 stations in the central part of Japan's Main Island and in Hokkaido, we found five new karyotypes, considered to be variations of tetraploidy and diploidy: 4n?fis1. + 1 = 3SM + 2A + 3T1 + 2T2 + 4M = 14, 4n?fis2.(B) = 2SM + 2A + 4T1 + 2T2 + 4M + (0?2B) = 14 –16, 4n?fis2. + 1 = 2SM + 2A + 4T1 + 2T2+5M= 15, 4n?fis2.?2 = 2SM + 2A + 4T1 + 4M = 12, and 2nM- = 2SM + 2A = 4 (where SM = submetacentric; A = acrocentric; T1 and T2 = telocentric; M = metacentric; B = B-chromosome; fis1. and fis2. = occurrence of one or two centric fissions, respectively; and M- = deletion of a metacentric chromosome). These karyotypes exist singly in one individual or as various mixoploids within the same individual. No individual having only karyotype 2nM- has yet been found. This brings the total number of known karyotypes in P. auriculata to 17; these can be arranged in an order that we believe reflects their evolution. |
| |
Keywords: | Turbellaria chromosomal polymorphism mixoploidy differentiation of karyotype |
本文献已被 SpringerLink 等数据库收录! |
|