CARYOLOGIA Vol. 58, no. 4: 293-299, 2005 (1240)
Cytogenetic study on three species of the genus Triatoma
(Heteroptera: Reduviidae) with emphasis on nucleolar organizer regions
Severi-Aguiar * Grasiela Dias de Campos and Maria Tercı´lia Vilela de Azeredo-Oliveira
Departamento de Biologia, Instituto de Biocieˆncias, Letras e Cieˆncias Exatas, IBILCE-UNESP, Rua Cristo´ va˜o Colombo
n°2265, Caixa Postal 136, Sa˜o Jose´ do Rio Preto, CEP 15054-000, Sa˜o Paulo, Brasil. Fax +55 17 32212380.
Abstrat — The use of banding techniques allows the recognition of chromosomal pairs and karyotypical arrangements.
However, its application in Heteroptera holocentric chromosomes is limited. Thus, little is known about their
structure, specially their Nucleolar Organizer Regions (NORs). A comparative analysis of the nucleolar characteristics
present during spermatogenesis in Triatoma platensis, Triatoma protacta and Triatoma tibiamaculata seems to indicate
that in this group of insects nucleolar fragmentation occurs after prophase I. The study of chromosomal structure
of these triatomines indicates that NORs are located at some telomeric and interstitial autosome regions and at
sexual chromosomes (X/X1X2).
Key words: holocentric chromosomes, NOR, nucleolar fragmentation, silver impregnation, spermatogenesis, triatomines.
CARYOLOGIA Vol. 58, no. 4: 300-307, 2005 (1262)
Genome interrelationship in the genus Eleusine (Poaceae) as revealed through heteroploid crosses
Devarumath Rachayya Mallikharjun1, Subhash C. Hiremath2, Satyawada Rama Rao*3, Arun Kumar3 and Suman Shivamurti Sheelavanthmath4
1 Laboratory of Cellular and Molecular Cytogenetics, Department of Botany, Delhi University, Delhi 110 007, India.
2 Department of Botany, Karnataka University, Dharwad 580 003, India.
3 Cytogenetics and Molecular Biology Laboratory, Department of Botany, J. N. V. University, Jodhpur- 342 005, India.
4 Tissue Culture Section, Vasantdada Sugar Institute, Manjari (BK), Pune 412307, India.
Abstract — Genome interrelationship in the genus Eleusine (Poaceae) has always been a matter of considerable interest
for plant breeders whose major objective was to attain genetic improvement in E. coracana (finger millet), an
important crop of Africa and south Asia. E. coracana and E. africana are the two major amphidiploid species of Eleusine
with AABB genome (2n=4x=36). In attempt to identify the A and B genome donor species, heteroploid crosses
were made involving these two tetraploid species and four diploid species viz. E. intermdia, E. indica, E. floccifolia, E.
tristachya (all with 2n=2x=18). The resultant F1 hybrids were investigated for cytomorphological details. Male meiosis
studies in pollen mother cells showed regular occurrence of expected 9II+9I at diakinesis/ metaphase I in majority
of the cells indicating the existence of complete and/or partial homology among crossing parents. The occurrence
of occasional quadrivalents had apparently no bearing on the course of meiosis owing to their scant number. Anaphase
I and II were characterized by unequal distribution and micronuclei leading to drastic reduction in pollen
stainability (2-8%) and complete seed seterlity. Our observations suggest that E. indica with AA genome is the pivotal
donor species in the evolution of E. africana and E. coracana while E. intermedia (AimAim) and E. tristachya (AtAt)
belong to A genomic group of diploid Eleusines. Further these three species form a close genetic assemblage within
the genus Eleusine. The assumption that E.floccifolia is a definite B genome donor species is now widely accepted
while E. tristachya might also be a candidate for BB genome is completely ruled out there by leaving the question
wide open regarding identity of the other B genome donor species, if any.
CARYOLOGIA Vol. 58, no. 4: 308-314, 2005 (1273)
Isochore, Intasome, Prosome, Proteasome, Proteosome, Plasmatosome, Plasome, Platysome, Primosome: a terminological comment
Battaglia* Emilio
Dipartimento di Scienze Botaniche, Via L. Ghini 5, 56126 Pisa, Italy; fax ++39050551345
Dedicated to the memory of J. William Fulbright
Abstract—The author briefly underlines the higlhly chaotic and sometimes contradictory state of affairs of current
biological terminology, historically acquired, as well as the effect of modern negligence towards the classical languages,
Greek and Latin.
In the present account, several terms of considerable biological interest such as isochore, intasome, prosome, proteasome,
proteosome, plasmatosome, plasome, platysome, primosome are taken into critical consideration, mainly from
the linguistic point of view, and a corresponding alternative terminology is brought to the attention of biologists. The
author also emphasizes the need of quoting all terms in scientific dictionaries, wether obsolete or inapropriate, together
with their paternity, in order to avoid any future re-coinage or re-proposal.
Key words: chromatinosome, chromatinsome, chromatosome, chromosome, genochore, genomere, homochoric,
heterochoric, int-some, intasome, integrasome, isochore, isogenochore, plasmatosome, plasmasome, plasmosome,
plasome, platysome, primosome, programmasome, prosoma, prosome, proteosome, proteasome, archiproteasome,
basiproteasome, deuteroproteasome, protoproteasome, multiproteasome.
CARYOLOGIA Vol. 58, no. 4: 315-319, 2005 (1324)
Meiotic analysis of two putative polyploid species of Verbenaceae from Brazil.
Dias Brandao1 Aline, Lyderson Facio Viccini2 and Shirlei Maria Recco-Pimentel1*
1 Departamento de Biologia Celular, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP
6109, 13083-863 Campinas, SP, Brazil.
2 Departamento de Biologia, Instituto de Cieˆncias Biolo´ gicas, Universidade Federal de Juiz de Fora (UFJF), CEP
36036-330 Juiz de Fora, MG, Brazil.
Abstract—The natural occurrence of hybrids and polyploids hinders the precise identification of some taxa in Verbenaceae
(Lamiales). Since meiotic studies are useful for understanding the chromosomal behavior of plant species,
we have examined the meiotic stages and chromosomal behavior of Lippia alba (Mill) N. E. Brown and Lantana camara
Plum. in Brazil. Lippia alba and Lantana camara, had normal stages of meiosis, including interphase, leptotene,
zygotene, pachytene, diplotene, initial diakinesis, diakinesis, metaphase I, anaphase I, telophase I, prophase II and
telophase II. Fifteen and 22 bivalents were observed during diplotene and diakinesis in L. alba and L. camara, respectively.
The chromosomes segregated normally during anaphase I, telophase I and II. The regular meiotic behavior
seen in L. alba and L. camara indicated that polyploidy was established by a diploid-like behavior in meiosis, although
this did not exclude a possible diploid origin.
CARYOLOGIA Vol. 58, no. 4: 320-331, 2005 (1333)
Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium
Hongguan1* Tang, Meng Lihua2*, Ao Shiqimg1 and Liu Jianquaan1,2**
1 Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000, China.
2 Qinghai-Tibet Plateau Biological Evolution and Adaptation Laboratory, Northwest Plateau Institute of Biology,
the Chinese Academy of Sciences, Xining 810001, Qinghai, China.
Abstract — Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply
within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed
to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of
its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n =
20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in
the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported.
The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric
chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly
different from that of most Allium species occurring in the plateau through a complete comparison of all available
species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure
were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this
similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum
of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly
placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing
asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately
in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the
chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary
climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant
morphology from their progenitors.
CARYOLOGIA Vol. 58, no. 4: 332-338, 2005 (1335)
Karyotype analysis in Chaetanthera chilensis (Willd.) DC. And Chaetanthera ciliata Ruiz et Pavo´n (Asteraceae) by double fluorescence in situ hybridization
Baeza Perry1* Carlos Marcelo and Otto Schrader2,*
1 Departamento de Bota´nica, Universidad de Concepcio´n, Casilla 160−C, Concepcio´n, Chile.
2 Federal Centre for Breeding Research on Cultivated Plants, Institute of Horticultural Crops, Neuer Weg 22/23,
06484 Quedlinburg, Germany.
Abstract — Karyotypes of Chaetanthera ciliata and C. chilensis from Chile were examined using the location of the
5S and 18S/25S rDNA gene sequences. Signals of 5S and 18/25S rDNA are seen in 4 and 5 of the 11 chromosome
pairs in C. ciliata and C. chilensis, respectively. The reported karyotypes are symmetric with small chromosomes and
a great similarity among them. Chromosome asymmetry indexes (AsI % and A1) were similar for both species. This
report is the first on chromosome number and karyotype analysis of Chaetanthera ciliata and C. chilensis. One of the
remarkable differences between the karyotypes of C. ciliata and C. chilensis is that C. ciliata has only metacentric
chromosomes, whereas C. chilensis has a submetacentric chromosome pair. Using the FISH technique, notable differences
can be observed with respect to the position and number of rDNA sequences depending on the chromosome.
Key words: Chaetanthera, FISH, karyotype, physical mapping, South America, 5S and 18/25S rRNA gene loci.
CARYOLOGIA Vol. 58, no. 4: 339-344, 2005 (1339)
Hoplosternum littorale (Teleostei, Callichthyidae) from a Coastal River basin in Brazil − Cytogenetic analysis and gene mapping of 5S and 18S rDNA
Pazza1* Rubens, Karine Frehner Kavalco1, Lurdes Foresti de Almeida-Toledo1 and
Luiz Antonio Carlos Bertollo2
1 Universidade de Sa˜o Paulo—USP, Instituto de Biocieˆncias, Departamento de Gene´tica e Biologia Evolutiva. Rua
do Mata˜o, 277 — Edifı´cio Andre´ Dreyfus, Cidade Universita´ria, ZIP 05508090, Sa˜o Paulo — SP — Brazil. Phone:
+55(11)3091-7554.
2 Universidade Federal de Sa˜o Carlos — UFSCar — Depto. Gene´tica e Evoluc¸a˜o. Rodovia Washington Luı´s, km
235, ZIP 13565-905, Sa˜o Carlos—SP —Brazil. Phone/fax: +55 (16) 260-8377.
Abstract—Cytogenetic studies were carried out in a population of Hoplosternum littorale from a coastal river basin
in the southeastern region of Brazil. The results were identical to those of all populations already described for this
species, involving the maintenance of karyotype macrostructure and the distribution pattern of heterochromatin, as
well as its composition. The report on localization of ribosomal genes is new for this species. The diploid number
observed was 2n=60 chromosomes (6M+2SM+52A) for both sexes. A single pair of acrocentric chromosomes bearing
rDNA sites on the short arms was identified, both by silver nitrate staining and by FISH (Fluorescent in situ hybridization)
with an 18S rDNA probe. Four 5S rDNA clusters were identified using FISH methodology. C-banding
revealed a great amount of heterochromatin blocks, present in most chromosomes, preferentially located in subterminal
and interstitial regions. Four GC-rich regions were identified by chromomycin A3 staining. The data are discussed
based on ecological and genetic aspects of this fish group.
Key words: Callichthyidae, fluorescent in situ hybridization (FISH), Hoplosternum littorale, neotropical fish.
CARYOLOGIA Vol. 58, no. 4: 345-358, 2005 (1340)
Cytogenetic variability in species of genus Chironomus (Diptera, Chironomidae) from Poland
Paraskeva Michailova1*, Elz˙bieta Warchałowska-S´ liwa2, Boris Krastanov1 and Andrzej Kownacki3
1 Institute of Zoology, Bulgarian Academy of Sciences, blv. Tzar Osvoboditel 1, 1000 Sofia, Bulgaria.
2 Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, str. Slawkowska 17, 31-016 Krakow,
Poland.
3 Karol Starmach Institute of Freshwater Biology, Polish Academy of Sciences, str. Slawkowska 17, 31 − 016 Krakow,
Poland.
Abstract — Chromosome variability was analyzed in three Chironomus species: Chironomus plumosus L., Chironomus
muratensis Ryser, Scholl & Wulker, and Chironomus annularius Meigen, from the natural populations
in Poland. A comparative analysis of band sequences with other Palearctic populations was done. Chromosome
band sequences of C. plumosus and C. muratensis did not differ from other Palearctic populations. A new homozygous
band sequence was discovered in C. annularius. The ten sequences observed in the Polish populations of
C. plumosus were represented in all cytogenetically studied European populations of this species. However, these sequences
showed substantial interpopulational variation and they didn’t demonstrate any geographical gradient.
Some of the inversions in C. plumosus and C. annularius were also involved in the function of the so-called polymorphic
system. The sensitivity of important chromosome structures (BRs and NOR) in the polytene chromosomes of C.
annularius to organic contaminants in the studied area was presented. The morphology of the additional “B” chromosome
found in C. plumosus can vary in different salivary gland cells. The existence of the “B” chromosome in the C. plumosus genome was considered in the light of its selective value in the studied area.
Key words: aberrations, additional “B” chromosome, Chironomus, polymorphic system, polytene chromosomes.
CARYOLOGIA Vol. 58, no. 4: 359-366, 2005 (1346)
Cytogenetic Analysis of eight Lily Genotypes
Marasek1 Agnieszka, ElwiraS´ liwin´ska2, Teresa Orlikowska*1
1 Research Institute of Pomology and Floriculture, Pomologiczna St 18, 96 - 100, Skierniewice, Poland. Phone. 48 46
833 20 21, fax: +48 46 833 42 26, e- mail: torlikow@insad.pl. 2 Department of Genetics and Plant Breeding, University
of Technology and Agriculture, Kaliskiego St 7, 85-789 Bydgoszcz, Poland.
Abstract — Chromosomal banding markers were established for four lily species - L. candidum, L. × formolongi, L.
henryi, L. pumilum and four belonging to horticultural group Oriental hybrids - cultivars - ‘Alma Ata’, ‘Expression’,
‘Marco Polo’ and ‘Muscadet’. Banding markers were provided by Ag-NOR, CMA3/DA/DAPI and C-Giemsa stainings.
These techniques enabled to establish markers for identification from 4 to 17 out of 24 chromosomes depending
on genotype and technique. Negative DAPI bands were not always observed whereas Ag-NOR and CMA3 bands
were distinctly visible on chromosomes and co-localized the positions of secondary constrictions which enabled to
distinguish primary from secondary constrictions, even if these structures were localized close to each other. Additional
CMA3 bands were present intercalary on chromosomes. The C banding method revealed the most markers for
chromosomes identification but the technique was difficult to standardisation and results were not fully reproducible.
For each genotype tested relative DNA content was evaluated.
Key words: C-banding; CMA3/DA/DAPI banding; karyotyping; Lilium spp.; silver staining.
CARYOLOGIA Vol. 58, no. 4: 367-373, 2005 (1347)
Meiotic nuclear restitution mechanisms in a triploid lily
Errico1* Angela, Maria Cammareri2 and Clara Conicella2
1 Dept. of Soil, Plant and Environmental Sciences, University of Naples “Federico II”, Via Universita` 100, 80055
Portici, Italy.
2 CNR-IGV, Research Institute of Plant Genetics, Research Division: Portici, Via Universita` 133, 80055 Portici,
Italy.
Abstract — Chromosome number and pollen stainability were evaluated in Lilium L. species (L. formosanum, L.
miryophillum, L. regale), and in cultivars coming from Asiatic (Elite, Pollyanna, Vivaldi) and Oriental hybrid group
(Cascade, Casablanca, Galilei). All the genotypes are diploid (2n=2x=24) except cv. Elite which results triploid
(2n=3x=36). The pollen stainability ranged from 90 to 98% among diploids and from 80 to 90% in the triploid
which exhibited pollen grains of different size, as well.
A detailed analysis of microsporogenesis was carried out in the triploid cultivar. The chromosome associations at diakinesis
were either trivalents or bivalents and univalents. Anaphases I and II exhibited lagging chromosomes and unequal
distribution of chromosomes at the two poles. Single and double bridges plus acentric fragments formed possibly
due to a paracentric inversion.
Meiotic nuclear restitution mechanisms occurred following the failure of the reductional wall or, alternatively, of the
equational wall. The analysis of sporads evidenced tetrads as well as dyads, triads and rare monads and poliads.
Key words: cytokinesis, Lilium, meiosis, pollen
CARYOLOGIA Vol. 58, no. 4: 374-379, 2005 (1353)
Functionality of major and minor 45S rDNA sites in different diploid wild species and varieties of sunflowers
De Paula Wilson B.M., Juca A.B. San-Martin, Priscila Boneventi, Jose´ Marcelo D. Torezan and Andre´ Luı´s L. Vanzela *
Laborato´ rio de Biodiversidade e Restaurac¸a˜o de Ecossistemas, Departamento de Biologia Geral, Centro de Cieˆncias
Biolo´ gicas, Universidade Estadual de Londrina, Campus Universita´rio, 86051-990, Londrina, Parana´, Brazil. Phone
and fax number: +55 43 3371 4417.
Abstract—The genus Helianthus includes diploid (2n = 2x = 34), tetraploid (2n = 4x = 68) and hexaploid (2n = 6x
= 102) species, and genome evolution based on extensive diversity due to free hybridization, introgression and polyploidy.
The wild diploid species H. debilis, H. praecox and H. nuttallii showed 2n=34 with four 45S rDNA sites. The
cultivated sunflower (H. annuus), also diploid, showed six and eight 45S rDNA sites, being six major and two minor
terminal rDNA sites. Samples were studied using C-CMA3 and NOR banding to determinate the functionality of minor
45S rDNA sites. Additionally, FISH with 45S and 5S rDNA probes were performed. Results showed that the
number and the position of 45S and 5S rDNA sites maintenance in cultivated karyotypes, but provide evidence of a
possible increasing in number of rDNA 45S sites when compared with the wild diploid species. Besides, results of
C-CMA3 and NOR banding showed that the minor sites are not associated with GC-rich heterochromatin but, even
thus, are functional.
Key words: Ag-NOR, C-CMA3 banding, FISH, Helianthus, rDNA.
CARYOLOGIA Vol. 58, no. 4: 380-386, 2005 (1356)
Karyology of four Indian snakes
Sharma * Om Parkash and Gurpreet Kour **
Department of Zoology, University of Jammu, J&K- 180006 (India)
Abstract — Cytogenetic studies were carried out on four species of Indian snakes viz Eryx conicus (Family Boidae),
Naja naja naja (Family Elapidae), Vipera russelli and Echis carinatus (Family Viperidae) collected from Jammu region
(J&K). Both E. conicus and N. n. naja show deviation from typical ophidian karyotype (2n=36), having 2n=34 (16
macro- and 18 microchromosomes, NF=42) in E. conicus and 2n=38 (16 macro- and 22 microchromosomes and
NF=50) in N. n. naja. In both the species sex chromosomes are undifferentiated. V. russelli and E. carinatus exhibited
typical ophidian karyotype viz 2n=36 (16 macro- and 20 microchromosomes) with NF=48 and 50 respectively.
They possess a well differentiated ‘ZW’ sex mechanism in female, where ‘W’ is smaller and submetacentric, a final
step in the evolution of sex chromosome in snakes and ‘Z’ is larger and metacentric.
Key Words: Boidae, Cytogenetics, Elapidae, Microchromosomes, Viperidae
CARYOLOGIA Vol. 58, no. 4: 387-395, 2005 (1358)
Comparative cytogenetics of nine species of Hypoptopomatinae (Teleostei: Siluriformes: Loricariidae): the importance of structural rearrangements in chromosome evolution
Ferreira Daniela Cristina, Ma´rcio Ce´sar Chiachio, Adriana Kazue Takako, Artur Antonio Andreata, Fausto Foresti and Claudio Oliveira *
Universidade Estadual Paulista, Instituto de Biocieˆncias, Departamento de Morfologia, 18618-000, Botucatu, SP,
Brazil
Abstract — Fishes of the subfamily Hypoptopomatinae are very common and found in the lowlands of cis-Andean
South America from Venezuela to the north of Argentina. With the main objective of contributing for a better understanding
of the importance of chromosome rearrangements in the loricariid evolution, cytogenetic analyses were
conducted in nine species of Hypoptopomatinae. The results showed a marked gross karyotypic conservation with
the presence of 2n=54 chromosomes in all species analyzed. The main differences were found in the karyotypic formulae
level. Most species had a single interstitial Ag-NORs, however terminal Ag-NORs were observed in three species.
One species exhibited two Ag-NOR-bearing chromosome pairs. The distribution of C-band positive segments
was species specific but chromosome markers were observed among the species analyzed. The gross cytogenetic
characteristics observed among the Hypoptopomatinae species are similar to those observed in other primitive Loricariidae
species suggesting that small changes, mainly paracentric and pericentric inversion were the main events in
the karyotypic evolution of this fish group.
Key words: Ag-NORs, C-band, chromosome evolution, fish cytogenetics, karyotypes.
CARYOLOGIA Vol. 58, no. 4: 396-402, 2005 (1366)
Abnormal meiotic behavior in Brachiaria brizantha (Poaceae) leading to microspore degeneration
Mendes Vieira1 Daniela, Andrea Beatriz Mendes Bonato1, Maria Suely Pagliarini1* and Cacilda Borges Do Valle2
1 Department of Cell Biology and Genetics, State University of Maringa´, 87020-900 Maringa´ PR Brazil.
2 Embrapa Beef Cattle, P.O. Box 154, 79002-970 Campo Grande MS Brazil.
Abstract — The current paper reports an original abnormality recorded in one accession of Brachiaria brizantha
(B003) of the Brazilian germplasm collection for the genus Brachiaria maintained at Embrapa Beef Cattle. Among 25
inflorescences analyzed, 15 presented an abnormality affecting several phases of microsporogenesis. The abnormality
appeared after nucleolus disintegration at diakinesis and was recorded till the end of meiosis. In affected inflorescences,
bivalents were not able to congregate in a metaphase plate, remaining scattered or sometimes grouped in the
cytoplasm. They then gave rise to pycnotic nuclei of different sizes that were later rejoined into telophase nuclei allocated
peripherically. Anaphases I were never seen. After the first cytokinesis, the meiocytes entered meiosis II. In
prophase II, nuclei presented abnormal positions. In metaphase II, once more, metaphase plates were not observed
and chromosomes were grouped into two small and pycnotic nuclei sometimes irregularly located. From telophase
II, independently of nuclei position, some meiocytes underwent the second cytokinesis, but the majority of meiotic
products was characterized by dyads. Independently of the origins, microspores degenerated as soon as they were
released, acquiring irregular shapes, and becoming intensely stained. At the end, nuclei degenerated and microspores
gave rise to an amorphous mass. Pollen grains were not found in the affected inflorescences. The importance
of this abnormality for Brachiaria breeding is discussed.
Key words: apoptosis, Brachiaria brizantha, grass, microspore degeneration, microsporogenesis, spindle, sterility.
CARYOLOGIA Vol. 58, no. 4: 403-409, 2005 (1378)
Low chromosome number angiosperms
Cremonini Roberto
Department of Botanical Sciences, University of Pisa, Via L. Ghini 5, 56126 Pisa, Italy; fax 039 050 2215380; e-mail:
cremonio@dsb.unipi.it
Abstract—Plant with very low chromosome number are of interest for the analysis of the structure of chromosome
and chromatin organization. Many studies have been carried out on the evolution of the karyotype in the Angiosperms
with only two chromosomes in their haploid complement. The results of these analyses in the five Angiosperms
with 2n=4 have been reported with the aim to provide further insight into the origin and the organization
of their chromosomes.
Key words: Brachycome, Colpodium, Haplopappus, Ornitogalum, plant chromosomes, Zingeria.