摘要:

A variety of plant species and cultivars were stained for chromocenters using the barium hydroxide, sodium saline citrate (SSC), Giemsa procedure (DNA denaturation, incubation-renaturation, staining), in order to test the hypothesis that larger (biomass) species have larger, more numerous, and more intensely-staining chromocenters. In all species and cultivars examined, results confirmed the hypothesis. Since chromocenters are believed to be composed primarily of heterochromatin/repetitive DNA (which has been postulated to shorten the cell cycle), it is likely that chromocenters modulate species size/biomass. Among closely related species, larger/more biomassive cultivars contained larger, more numerous, and more intensely-staining chromocenters than smaller/less biomassive cultivars.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797365

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

Karyotypes of five males and four females of Eurasian (Siberian) flying squirrel,Pteromys volans orii, were analyzed with G-, C-, Ag-NOR staining methods. Fluorescencein situhybridization (FISH) was applied to the location of 18S and 28S ribosomal RNA genes. The diploid chromosome number of this species was 2n= 38 with the arm number (NF) of 68. C-bands were located at the centromeric region of all chromosome pairs. Nucleolus organizer regions (NORs) appeared in the short arm of chromosome 17, and the location of Ag-NORs was indistinguishable from the site of the rRNA genes. The size variation of NORs was observed in each individual, indicating heteromorphism of NORs in this species.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797366

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

New crossing and selfing experiments withinAchillea millefoliumagg. (Compositae) succeeded with tetraploid individuals ofA. ceretanica-4 x,A. collina, A. pratensisand F1hybrids. Chromosome numbers of 105 out of 785 individuals including F1, BC, S1offsprings and free pollinated F1progenies were studied. Generally, plants were tetraploid, but occasionally aneuploids and a near-pentaploid plant originated from crossing and selfing experiments withA. ceretanica-4xandA. collina.The high degree of selfincompatibility withinAchillea millefoliumagg. is confirmed.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797367

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

The chromosomes of 346 specimens ofMytilus galloprovincialis, collected at four NW Iberian peninsula sites, were studied using a C-banding technique. Polymorphism for C-banding was detected. According to the banding patterns, three classes of mussels could be distinguished: 1) individuals showing two pairs of submeta/subtelocentric chromosomes bearing NOR-associated heterochromatic regions terminal to their long arms, 2) mussels presenting additional C-bands located at other positions on the NOR-bearing chromosomes or on other chromosomes, and 3) mosaic mussels. The location of the additional C-band positive regions was similar in the four populations studied.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797368

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

A karyometric analysis of the olive fly,Bactrocera oleae, was carried out. Results obtained showed that the diploid set ofB. oleaeis composed of 12 chromosomes. The haploid karyotype is composed of 4 submetacentric and 1 metacentric autosomes, a dot-like Y chromosome and a submetacentric or metacentric X chromosome. A polymorphism is present on the X chromosome and it is due to a satellite on the short arm of the chromosome. A secondary constriction is present on the third pair of chromosomes. Study of specimens collected from different localities in Central Italy, Sardinia and Southern Italy showed that as concerns the satellite polymorphism, only females from Southern Italy are not in Hardy Weinberg balance. This female population seems to have an excess of homozygous specimens (with or without satellite) while there appear to be fewer heterozygous specimens than expected. C-banding revealed centromeric bands on the five pairs of autosomes, a subcentromeric band on the long arm of the second pair, the short arm entirely banded and a large subcentromeric band on the X chromosome. The Y chromosome was completely banded.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797369

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

Chromosome numbers for six species ofMonoxia(Coleoptera: Chrysomelidae: Galerucinae) fall in two main groups: species with 9 or 10 bivalents and species with 16 or 19 bivalents. The sex determination system is Xyr(possibly neoXY). The intrageneric classification ofMonoxiais now based on congruent cytological, morphological, and host plant feeding information.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797370

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

Peripheral blood cultures from 16 goats (Capra hircus, 2n= 60) were set up to arrange GTG-, GBG-, RBA-, and RBG-banded karyotypes at the prometaphase state according to the goat RBA-standard karyotype. Only the position of chromosomes 4 and 6, as well as that of chromosomes 25 and 29, were inverted according to the cattle standard and to cattle rob (1;29) p-arms. G-and R-banded ideogrammatic representations of goat chromosomes are also repoted using only one common banding nomenclature.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797371

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

Karyotypes of 13 species from Taiwan (9 species) and from Holland (4 species) belonging to the families Aphalaridae, Psyllidae, Homotomodae, Carsidaridae, and Triozidae are described for the first time. Karyotypes ofBactericera maura, Cacopsylla hippophaeus, Dynopsylla pinnativena, Leptynoptera sulfurea, Macrohomotoma gladiata, Paurocepbala chonchainensis, P. sauteri, P. trematos, Sympauropsylla triozoneura, andTenaphalara acutipenniswere 2n= 24 + X0. However, the karyotypes of three species are as follows:Cacopsylla sorbi2n= 20 + XY,Heteropsylla cubana2n= 24 + XY, andTrioza remota2n= 14+ X0.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797372

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

Seven entities ofHieraciumsubg.Hieraciumgrowing in the volcanic area of Mt Amiata were investigated from a karyological viewpoint. Three ploidy levels were found, all with 9 as base number:H. racemosumandH. virgaurea, which belong to the sect.ItalicaFries have 2n= 18 chromosomes with a variable number of terminal satellites;H. sabaudum, H. umbellatum, H. murorumandH. grovesianumhave 2n= 27 chromosomes and probably are agamospermic entities maintaining their morphological identity thanks to the absence of gene-exchange (H. sabaudum-H. umbellatum) or maybe ecological differentiation (H. murorum-H. grovesianum); finallyH. neuropicola, a representative of theH. pallidumgroup that colonizes the trachytic rocks on the top of the mountain, is characterized by a tetraploid set of 36 chromosomes. The finding of diploid populations appears worth evidencing because it provides confirmatory data to the hypothesis of the existence of diploid, maybe sexual and amphimictic cytotypes in Southern Europe. The presence of tri- and tetravalents in respectively triploid and tetraploid entities suggests their autoploid origin.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797373

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor

摘要:

This article reviews the types of numerical variation in chromosomes, with special emphasis on those organisms which have holocentric chromosomes. Terminological aspects are discussed with reference to monocentric as well as holocentric chromosomes. The termsymploidy(partial or total) is proposed to include ploidy levels generated by fusion of some or all of the set of chromosomes.

ISSN:0008-7114    

DOI:10.1080/00087114.1996.10797374

出版商:Taylor & Francis    

年代:1996

数据来源: Taylor