Search results for "chromosome number"

Karyotype variability and inter-population genomic differences in freshwater ostracods (Crustacea) showing geographical parthenogenesis

2018

Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820), where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH) within and among sexual and asexual populations to get insigh…

Karyological data of three Hieracium (Asteraceae) from Sicily and South Italy

2021

Chromosome numbers are given for three endemic Hieracium taxa from Sicily and Campania (Southern Italy). All the examined taxa resulted triploid (2n = 3x = 27). The triploid chromosome set found in the population of H. pallidum from Rocche dell’Argimusco (Peloritani Mountains, NE-Sicily) differs from the previous counts (2n = 4x = 36) reported for the same species from its locus classicus (Mt. Etna).

Reports (1813-1814) In: Kamari G., Blanché C., Siljak-Yakovlev S. (EDS) Mediterranean Chromosome Number Reports - 23

2013

Morphological, karyological and taxonomic remarks on Ferulago nodosa (L.) Boiss. (Apiaceae)

2012

Abstract Western (Sicilian) and eastern (Balcan-aegean) populations of the Balcan-tyrrhenian Ferulago nodosa are reported to be different in some morphological characters, and were considered different species by some authors in XIX century. In this work, fruit and pollen morphologies have been compared in Sicilian and Cretan plants; also, the chromosome number of Sicilian plants has been ascertained. Preliminary results highlight a general homogeneity between the two populations, nevertheless showing significant differences in some parameters (fruit form, pollen size). For this reason, and considering the geographic disjunction of the Sicilian plants, the two populations are proposed to be…

<i>Limonium marisolii</i> L. Llorens (Plumbaginaceae) revisited

1998

A new triploid agamic species, L. leonardi-llorensii , is described from coastal populations of South-West Mallorca. The new species is closely related, on morphological grounds, to the endemic L. marisolii L. Llorens, from which it could be distinguished by several morphological characters (leaves without papillae, longer calyx, more flowers per spikelet) and by a different chromosome number ( 2n = 26, L. leonardi-llorensii ; 2n = 27, L. marisolii ). The relationships between both species are discussed, and it is suggested that both taxa might share some common evolutionary history despite their divergent chromosome number. The origin of L. marisolii from L. leonardi-llorensii through chro…

Karyological data of four geophytes native to Tunisia

2021

Chromosome numbers were studied in four geophytes collected in Tunisia. Allium pallens was collected from Zembra island, N of Tunisia, while Drimia purpurascens, Oncostema peruvianum and Pancratium foetidum from continental Tunisia. The chromosome numbers found for Allium pallens, Drimia purpurascens, and Oncostema peruvianum coincides with the previous reports obtained from other Mediterranean populations. The chromosome number 2n = 22, found on material from Toujane is the first reported for Pancratium foetidum.

The genus Isoëtes L. (Lycophyta, Isoëtaceae): Synthesis of karyological data

2001

Summary A synthesis of relevant karyological data regarding the genus Isoetes is given, with an up-to-date check list of chromosome numbers including 152 records referring to 67 taxa (62 species and 5 infraspecific taxa) and 16 hybrids. Total of different chromosome counts (considering two or more cytotypes for certain taxa, excluding hybrids) is 80. Probable base number is x = 11, even though x = 10 and x = 12 have been proposed for certain species. On the basis of data here summarized, the mean percentage of polyploidy is 61.2%; 31 taxa are diploids (38.8%), 28 are tetraploids (35.0%), 8 are hexaploids (10.0%), with a few species each which are tri-, penta-, octo-, deca- and dodeca-ploids…

The tropical African genus Morgenia (Orthoptera, Tettigoniidae, Phaneropterinae) with emphasis on the spur at the mid tibia

2018

The authors revised the genus Morgenia Karsch, 1890 which now consists of eight species, of which three are here newly described (Morgeniaplurimaculata Massa & Moulin, sp. n., M.angustipinnata Massa, sp. n., and M.lehmannorum Heller & Massa, sp. n.). Six of the eight species occur in the Tri National Sangha (TNS) comprising Dzanga-Sangha Special Reserve and Dzanga Ndoki National Park (Central African Republic), whose high biodiversity has been recently highlighted. In particular the genus is characterised by the presence of a more or less long spur at the inner mid tibia, different in each species; in M.modulata, it moved lower down into a new position at about ¼ of tibia, w…

An updated catalogue of chromosome numbers in the genus Isoetes L. (Isoetaceae, Lycopodiophyta)

2010

Chromosomes of the Parasitic Isopod Anilocra Physodes

1996

AbstractCounts of mitotic chromosomes have allowed to determine 2n = 12 as the modal diploid number of Anilocra physodes. Application of the C-banding technique reveals that two hetero-chromatic blocks bordering the centromeric region occur in each chromosome. This supports the notion that the actual low chromosome number of A. physodes may have been derived through a process of Robertsonian fusion.