Search results for "Ploidy"
showing 10 items of 299 documents
Chloroplast DNA and isozyme evidence on the evolution ofSenecio vulgaris (Asteraceae)
1997
Chloroplast DNA (cpDNA) and isozyme variation were analyzed over a range of populations of two infraspecific taxa of the tetraploidSenecio vulgaris. The isozyme data were supportive of the hypothesis that the weedy and cosmopolitanS. vulgaris var.vulgaris is an evolutionary derivative ofS. vulgaris subsp.denticulatus from the coasts of W Europe and montane altitudes in S Spain and Sicily. The two taxa exhibited a very high genetic identity with subsp.denticulatus containing slightly more isozyme diversity than was found in var.vulgaris. — Three cpDNA haplotypes (A, B, C) already known from other Mediterranean diploid species ofSenecio were resolved in var.vulgaris, and an additional fourth …
Morphological and genetic diversity within Pilosella hoppeana aggr. (Asteraceae) in Italy and taxonomic implications
2013
Morphological variation, ploidy level and genetic diversity have been studied on 10 populations of the Pilosella hoppeana aggr. from the Alps, Abruzzo, Calabria and Sicily.Chromosome counts showed that the plants from Abruzzo and those from Sicily are tetraploid (2n = 36); they are assigned to P. hoppeana subsp. macrantha. The plants from the Alps (P. hoppeana subsp. hoppeana) and those from Calabria are diploid. The Calabrian populations, previously included in P. hoppeana subsp. macrantha, are shown to belong to a separate species, P. leucopsilon. The principal component analysis, based on 25 morphological characters, allowed distinguishing clearly four groups. An allozymes study using 10…
New chromosome numbers for plant taxa endemic to the Balearic Islands
2006
Mitotic chromosome numbers are reported from 25 vascular plant taxa, endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers ofAnthyllis vulneraria subsp.balearica (2n=12),Cymbalaria fragilis (2n=56), andPolygonum romanum subsp.balearicum (2n=40) were determined for the first time. A new chromosome number was found in several populations ofAnthyllis hystrix (2n=70) suggesting that this species is decaploid, in contrast to an earlier work reporting a higher ploidy level (2n=12x=84). The new chromosome number 2n=32 was reported inHypericum hircinum subsp.cambessedesii. It is suggested that the previous count (2n=40) could be explained by the presence of a…
Karyotypes, Banding Patterns and Nuclear DNA Content inCrepidula unguiformisLamarck, 1822, andNaticarius stercusmuscarum(Gmelin, 1791) (Mollusca, Cae…
2009
ABSTRACT The chromosome complement and the nuclear DNA content in two caenogastropod species from the Mediterranean Sea, Crepidula unguiformis (Calyptraeidae) and Naticarius stercusmuscarum (Naticidae), were investigated by the application of both classical and molecular cytogenetic methods. Despite the constancy of haploid chromosome numbers (n = 17 in both species), C. unguiformis and N. stercusmuscarum show genome sizes amounting to 6.36 and 2.63 pg, respectively. Moreover, while N. stercusmuscarum resembles cytogenetically the other neotaenioglossan caenogastropods studied so far, C. unguiformis differs in: (i) number and location of rDNA clusters (ii), composition of telomeric repeats,…
Conventional karyotype, nucleolar organizer regions and genome size in five Mediterranean species of Syngnathidae (Pisces, Syngnathiformes)
1998
Conventional karyotypes, NOR-bearing chromosomes by means of silver impregnation and genome size were investigated in five Mediterranean species in three genera of the Syngnathidae. A karyotype of 48 subtelocentric-acrocentric chromosomes was found in the seahorse Hippocampus hippocampus (FN=48) while a diploid value of 44 occurred in H. guttulatus (2 sm-m+42 a; FN=46) and the pipefish Syngnathus abaster (44 a; FN=44) and S. typhle (44 a; FN=44). The pipefish Nerophis ophidion, possessing a diploid chromosomal set of 58 made up of 50 meta-submetacentric and eight subteloacrocentric elements (FN=108) and a genome size three to four times larger than those known to date, differs cytogenetical…
Chromosome studies of trematodesOpisthioglyphe ranae(Plagiorchiidae) from different populations
1995
Summary The diploid set of O. ranae from two localities, small rivers Penaquilla (Alicante province) and Gaibiel (Castellon province) in Spain, contain 22 chromosomes. The structure of karyotype was: 1st M+2nd T+3rd, 7–10 th SM+4th-6th ST+11th M-SM. Chromosomes of the first pair constitute 19.75% of the total haploid set length. A comparative karyological analysis of geographically separate O. ranae populations (from Spain, Poland and Crimea) showed the great karyological stability. Insignificant interpopulational differences in the morphology of 1st, 4th, 5th, 7th and 10th chromosome pairs were detected, which occurred as a result of small pericentric inversions.
Multiple sex-chromosome system and other karyological characterizations of Pterotrachea hippocampus (Mollusca: Mesogastropoda)
1993
Two modal diploid numbers of chromosomes were found for Pterotraches hippocampus Philippi (Mollusca: Mesogastropoda) collected from the Gulf of Palermo in 1990: 2n=31 and 32 for males and females, respectively. This, along with other karyological characteristics such as the occurrence of a trivalent configuration at diakinesis and two types of metaphase-II spreads in spermatocytes, supports the notion that a X1X2Y♂/X1X1X2X2♀ sex mechanism operates in the species investigated here. Silver nitrate procedure revealed an intraindividual variation in the Ag-staining pattern occurring in this species. The majority of the chromosome pair displayed terminal and/or interstitial heterochromatic block…
Karyotype analysis, nucleolus organizer regions and C-banding pattern of Eisenia foetida (oligochaeta, lumbricidae)
1991
The diploid number 2n=22 and haploid number n=11 found for Eisenia foetida from Palermo, Italy, confirm earlier data for this species from other localities. Analyses of silver-stained and C-banded mitotic and meiotic chromosomes suggest that a single chromosome pair has active NORs which correspond with C-positive regions. The occurrence of nucleolus activity during spermatogenesis of E. foetida is ascertained.
Functional analysis of 12 ORFs fromSaccharomyces cerevisiae chromosome II
1999
Twelve different ORFs have been deleted from the right arm of Saccharomyces cerevisiae chromosome II; namely YBR193c, YBR194w, YBR197c, YBR198c, YBR201w, YBR203w, YBR207w, YBR209w, YBR210w, YBR211c, YBR217w and YBR228w. Tetrad analysis of heterozygous deletant strains revealed that YBR193c, YBR198c and YBR211c are essential genes for vegetative growth. No effects were detected in any of the haploid deletion mutants for the rest of the ORFs with respect to growth, gross morphology or mating.
Amplified fragment length polymorphisms and sequence data in the phylogenetic analysis of polyploids: multiple origins of Veronica cymbalaria (Planta…
2007
Summary • The origin of polyploid Veronica cymbalaria (Plantaginaceae) was investigated using DNA sequence data and amplified fragment length polymorphism (AFLP) fingerprints to reveal the parentage of this taxon. The use of AFLP fingerprints in phylogenetic analysis is problematic and various methods have therefore been compared. • DNA sequence data (for the internal transcribed spacer (ITS) region and the plastid trnL-F region (trnL intron, 3’exon, and trnL-F spacer)) and polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis of the ITS region suggested a reliable hypothesis for the evolution of the V. cymbalaria complex. This hypothesis allowed evaluation …