Open AccessReduction of chromosome number in Eleocharis subarticulata (Cyperaceae) by multiple translocations
Author(s) -
DA SILVA CARLOS R. M.,
GONZÁLEZELIZONDO M. SOCORRO,
VANZELA ANDRÉ L. L.
Publication year - 2005
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1111/j.1095-8339.2005.00449.x
Subject(s) - biology , chromosomal translocation , cyperaceae , karyotype , chromatid , meiosis , chromosome , metaphase , anaphase , genetics , fluorescence in situ hybridization , microbiology and biotechnology , botany , poaceae , gene
Eleocharis subarticulata is recorded as the third species of Cyperaceae with a reduced chromosome number ( n = 3), following reports on Rhynchospora tenuis ( n = 2) and Fimbristylis umbellaris ( n = 3). For Eleocharis, the numbers recorded to date vary from 2 n = 10 to 2 n = c. 196, with x = 5 as the possible basic number. The karyotype of E. subarticulata was studied using conventional staining (mitosis and meiosis), C‐CMA 3 /DAPI banding, and FISH with 45S rDNA and telomere probes. The chromosomes showed no primary constrictions, as expected in the holocentric chromosomes of Cyperaceae. The meiotic behaviour was abnormal, with a single multivalent ring of six chromosomes at metaphase I, resulting from multiple translocations. At anaphase I six chromatids migrated to each pole, evidencing the inverted meiosis, and these groups were also visible at metaphase II. The C‐CMA 3 /DAPI banding technique showed only four terminal GC‐rich blocks. FISH with 45S rDNA probes revealed four terminal signals, probably associated with GC‐rich blocks. The telomeric probe located terminal signals in all the chromosomes, besides a hybridization site in the middle of the large pair. The occurrence of ectopic telomeric sites has not been described previously for plants with holokinetic karyotypes and with reduced chromosome numbers. These data reinforce the hypothesis of the reduction in chromosome number by multiple translocations. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 457–464.