The cytology of Brachycome. I. The subgenus Eubrachycome: A general survey

1970 ◽  
Vol 18 (1) ◽  
pp. 99 ◽  
Author(s):  
S Smith-White ◽  
CR Carter ◽  
HM Stace
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Base Number ◽  
Undescribed Species ◽  
General Survey ◽  
Chromosome Races ◽  
Chromosomal Change ◽  
Cytological Data ◽  
Wide Range ◽  
Annual Habit

Chromosome number determinations and cytological observations are reported for 37 recognized taxonomic species and varieties, and for a number of undescribed species and chromosome races in Eubrachycome. Additionally, chromosome numbers are reported for six species of Metabrachycome and two species of related genera. A wide range of numbers has been found. It is inferred that x = 9 is the primitive base number in the group. Eubrachycome has used various modes of chromosomal change, including polyploidy, amphidiploidy, decrease in base number, and the establishment of B. chromosomes. The present taxonomy of the group requires revision, taking into account cytological data. Primitive Eubrachycome was probably a mesic perennial. The evolution of desert species has involved reduction in chromosome number and the adoption of the annual habit, but other methods of desert adaptation have been available. Many species are chromosomally unstable, and may have been subject to catastrophic selection.

An investigation of chromosome numbers in the genus Brachiaria (Poaceae: Paniceae) in relation to morphology and taxonomy

1987 ◽  
Vol 65 (11) ◽  
pp. 2297-2309 ◽  
Author(s):  
G. P. Basappa ◽  
M. Muniyamma ◽  
C. C. Chinnappa
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Indian Subcontinent ◽  
Base Number ◽  
Chromosome Races ◽  
Morphological Studies

Determinations of chromosome number and morphological studies of 260 populations, belonging to 32 taxa, of the genus Brachiaria from the Indian subcontinent reveal that all sexually reproducing taxa have no chromosome races. Six agamic taxa, viz., B. brizantha var. brizantha (n = 27), B. brizantha var. ciliata (n = 18), B. decumbens (n = 18), B. hybrida (n = 27), B. mutica (n = 18), and B. setigera var. albistyla (n = 14), have consistently shown uniformity in chromosome numbers, based on x = 7, 8, and 9. Brachiaria setigera var. setigera, a genetically unstable apomict, is the only taxon that tends to have a heteroploid series (n = 16, 17, 18, 21, and 32). The population of B. setigera var. setigera with n = 17 is based on a secondary base number of x = 17. There are 6 diploids, 20 tetraploids, 5 hexaploids, and 3 octoploids in the genus. Aneuploidy and triploidy are characteristically absent in the genus, although their plausible existence in the B. setigera complex cannot be ruled out. In several species certain previously reported chromosome numbers that deviate from the present study are found to be the result of erroneous identifications or the result of taxonomically complex situations such as those found in B. brizantha, the B. distachya complex, and the B. ramosa complex.

scholarly journals Linking karyotypes with DNA barcodes: proposal for a new standard in chromosomal analysis with an example based on the study of Neotropical Nymphalidae (Lepidoptera)

2019 ◽  
Vol 13 (4) ◽  
pp. 435-449 ◽  
Author(s):  
Vladimir A. Lukhtanov ◽  
Yaroslavna Iashenkova
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Species Complex ◽  
Dna Barcode ◽  
Molecular Data ◽  
Published Data ◽  
Dna Barcodes ◽  
Undescribed Species ◽  
Species Identity ◽  
Chromosomal Data

Chromosomal data are important for taxonomists, cytogeneticists and evolutionary biologists; however, the value of these data decreases sharply if they are obtained for individuals with inaccurate species identification or unclear species identity. To avoid this problem, here we suggest linking each karyotyped sample with its DNA barcode, photograph and precise geographic data, providing an opportunity for unambiguous identification of described taxa and for delimitation of undescribed species. Using this approach, we present new data on chromosome number diversity in neotropical butterflies of the subfamily Biblidinae (genus Vila Kirby, 1871) and the tribe Ithomiini (genera Oleria Hübner, 1816, Ithomia Hübner, 1816, Godyris Boisduval, 1870, Hypothyris Hübner, 1821, Napeogenes Bates, 1862, Pseudoscada Godman et Salvin, 1879 and Hyposcada Godman et Salvin, 1879). Combining new and previously published data we show that the species complex Oleria onega (Hewitson, [1852]) includes three discrete chromosomal clusters (with haploid chromosome numbers n = 15, n = 22 and n = 30) and at least four DNA barcode clusters. Then we discuss how the incomplete connection between these chromosomal and molecular data (karyotypes and DNA barcodes were obtained for different sets of individuals) complicates the taxonomic interpretation of the discovered clusters.

Chromosome numbers and karyotypes in the Australian Gnaphalieae and Plucheeae (Asteraceae)

1999 ◽  
Vol 12 (6) ◽  
pp. 781 ◽  
Author(s):  
K. Watanabe ◽  
P. S. Short ◽  
T. Denda ◽  
N. Konishi ◽  
M. Ito ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Base Number ◽  
Generic Delimitation ◽  
First Time

Chromosome number determinations from 152 collections representing 42 genera and 106 species of the Australian Gnaphalieae and Plucheeae are reported. The chromosome numbers of 75 of these species have not been previously counted or differ from those previously reported for species. Chromosome numbers have been documented for the first time for 14 genera: Argyroglottis (n = 12), Cephalosorus (2n = 24), Decazesia (n = 14), Dielitzia (2n = 26), Eriochlamys (n = 14), Erymophyllum (n = 11 and 14), Gilruthia (n = 13), Leucochrysum (n = 9), Myriocephalus s. str. (n = 14, 2n = 24), Polycalymma s. str. (n = 14), Pterocaulon (n = 10), Pterochaeta (n = 12), Quinetia (2n – 24) and Sondottia (2n = 6). Remaining counts augment and agree with previously reported determinations. Some problems with generic delimitation and interpretation of chromosome data are outlined. There is an array of karyotypes within the Australian Gnaphalieae and dysploidy is widespread. Polyploidy has also played an important role in the evolution of some taxa. Evidence suggests that the base number for Australian Gnaphalieae is x = 14. This may be the base number for the entire tribe.

Chromosome numbers in the Boronieae (Rutaceae) and their bearing on the evolutionary development of the tribe in the Australian flora

1954 ◽  
Vol 2 (3) ◽  
pp. 287 ◽  
Author(s):  
S Smith-White
Keyword(s):  
Chromosome Numbers ◽  
Chromosomal Instability ◽  
Chromosomal Evolution ◽  
Basic Number ◽  
Evolutionary Development ◽  
Base Number ◽  
Polyploid Species ◽  
Cytological Data ◽  
Australian Flora ◽  
Two Stages

Chromosome numbers are reported for 69 species, belonging to 11 genera of the Boronieae. In comparison with the other divisions of the Rutaceae, chromosome numbers are remarkably variable, and base numbers range from 7 to 19. Seven genera and 10 species belonging to other tribes and subfamilies of the Rutaceae are also reported. In common with the Aurantoideae, Xanthoxyleae, and Ruteae, the primitive number in the Boronieae is almost certainly 9. Chromosomal evolution has involved both aneuploidy and polyploidy. In both diploid and polyploid species, chromosome pairing is essentially regular. All the polyploids, even within recognized taxonomic species, are essentially of allopolyploid constitution. Two stages in the occurrence of polyploidy can be recognized — the first giving rise to groups of generic status, and the second to polyploid species within genera. Many genera possess chromosome numbers which could be derived by aneuploid reduction, followed by polyploidy. Some fundamental change in chromosonle structure in the primitive Boronieae stock is suggested as a cause of its early chromosomal instability. From a correlation of geographical and cytological data and inference, a hypothesis of the historical development of the Boronieae in Australia is presented. Following their isolation in the continent, and the occurrence of a fundamental reorganization in chromosome structure, a period of generic radiation, with changes in basic number, occurred before the Miocene. Particular chromosome numbers are characteristic of genera. Differences in base number rank as generic rather than as specific criteria. On this basis the accepted taxonomy is essentially sound, and only minor alterations are suggested. Crowea is established, and Eriostemon lanceolatzis is separated from its congeners. Some sections of Boronia are deserving of generic rank, and B. serrulata is wrongly placed in the section Terminales.

Phylogenetics and chromosomal evolution in the Poaceae (grasses)

2004 ◽  
Vol 52 (1) ◽  
pp. 13 ◽  
Author(s):  
Khidir W. Hilu
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Chromosome Doubling ◽  
Chromosomal Evolution ◽  
Basic Chromosome Number ◽  
Basic Chromosome ◽  
Wide Range ◽  
The Family

The wide range in basic chromosome number (x = 2–18) and prevalence of polyploidy and hybridisation have resulted in contrasting views on chromosomal evolution in Poaceae. This study uses information on grass chromosome number and a consensus phylogeny to determine patterns of chromosomal evolution in the family. A chromosomal parsimony hypothesis is proposed that underscores (1) the evolution of the Joinvilleaceae/Ecdeiocoleaceae/Poaceae lineage from Restionaceae ancestors with x = 9, (2) aneuploid origin of x�=�11 in Ecdeiocoleaceae and Poaceae (Streptochaeta, Anomochlooideae), (3) reduction to x = 9, followed by chromosome doubling within Anomochlooideae to generate the x = 18 in Anomochloa, and (4) aneuploid increase from the ancestral x = 11 to x = 12 in Pharoideae and Puelioideae, and further diversification in remaining taxa (Fig. 3b). Higher basic chromosome numbers are maintained in basal taxa of all grass subfamilies, whereas smaller numbers are found in terminal species. This finding refutes the 'secondary polyploidy hypothesis', but partially supports the 'reduction hypothesis' previously proposed for chromosomal evolution in the Poaceae.

scholarly journals Genome size, chromosome number determination, and analysis of the repetitive elements in Cissus quadrangularis

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8201
Author(s):  
Duncan Kiragu Gichuki ◽  
Lu Ma ◽  
Zhenfei Zhu ◽  
Chang Du ◽  
Qingyun Li ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Chromosome Numbers ◽  
Arid Regions ◽  
Repetitive Elements ◽  
Repeat Elements ◽  
Cissus Quadrangularis ◽  
Wide Range ◽  
The Family ◽  
Animal Medicine

Cissus quadrangularis (Vitaceae) is a perennial climber endemic to Africa and is characterized by succulent angular stems. The plant grows in arid and semi-arid regions of Africa especially in the African savanna. The stem of C. quadrangularis has a wide range of applications in both human and animal medicine, but there is limited cytogenetic information available for this species. In this study, the chromosome number, genome size, and genome composition for C. quadrangularis were determined. Flow cytometry results indicated that the genome size of C. quadrangularis is approximately 2C = 1.410 pg. Fluorescence microscopy combined with DAPI stain showed the chromosome numbers to be 2n = 48. It is likely that C. quadrangularis has a tetraploid genome after considering the basic chromosome numbers in Cissus genus (n = 10, 11, or 12). A combination of low-throughput genome sequencing and bioinformatics analysis allowed identification and quantification of repetitive elements that make up about 52% of the C. quadrangularis genome, which was dominated by LTR-retrotransposons. Two LTR superfamilies were identified as Copia and Gypsy, with 24% and 15% of the annotated clusters, respectively. The comparison of repeat elements for C. quadrangularis, Vitis vinifera, and four other selected members in the Cissus genus revealed a high diversity in the repetitive element components, which could suggest recent amplification events in the Cissus genus. Our data provides a platform for further studies on the phylogeny and karyotype evolution in this genus and in the family Vitaceae.

Chromosome numbers and the taxonomy of North American Agalinis (Scrophulariaceae)

1984 ◽  
Vol 62 (3) ◽  
pp. 454-456 ◽  
Author(s):  
Judith M. Canne
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Base Number ◽  
Chromosome Counts ◽  
Base Chromosome Number ◽  
First Time

Chromosome counts are provided for 25 populations representing 18 species of Agalinis Raf. Chromosome numbers are reported for the first time for A. pinetorum, A. laxa, A. acuta, A. gattingeri, and A. skinneriana. The base chromosome number for section Linifoliae, section Heterophyllae, section Purpureae subsections Purpureae and Setaceae, and section Tenuifoliae is established at x = 14. Section Erectae and section Purpureae subsection Pedunculares have a base number of x = 13.

The cytology of Brachycome. II. The subgenus Metabrachycome: a general survey

1978 ◽  
Vol 26 (5) ◽  
pp. 699 ◽  
Author(s):  
CR Carter
Keyword(s):  
Chromosomal Rearrangements ◽  
Base Number ◽  
Ecological Diversity ◽  
Chromosome Counts ◽  
General Survey ◽  
Species Complexes ◽  
Wide Range ◽  
Relationship Of ◽  
The Relationship ◽  
Western Australian

Chromosome counts for 12 of the 17 known species of Metabrachycome are reported. All species have x = 9. Nine species are diploid (2n = 18), and the other three species show intraspecific polyploidy on base x = 9. Two of these three have a sexual diploid within the complex. The polyploids are probably apomictic. G. L. Davis recognized morphological 'varieties' within each of the three polyploid species complexes, but the relationship of these varieties to the various ploid levels is unclear. Metabrachycome, which is primarily Western Australian, exhibits a wide range of morphological and ecological diversity, yet it is chromosomally very conservative, with no change in chromosome base number, and no obvious karyotype differentiation. This contrasts sharply with the primarily eastern Eubrachycome which is extremely labile chromosomally, with base numbers ranging from n = 2 ton = 15. It is suggested that the more stable environment in Western Australia since the mid Tertiary may have been less conducive to the establishment and maintenance of chromosomal rearrangements.

CYTOGENETICS OF SOME SPECIES AND NATURAL HYBRIDS IN PROSOPIS (LEGUMINOSAE)

1975 ◽  
Vol 17 (2) ◽  
pp. 253-262 ◽  
Author(s):  
J. H. Hunziker ◽  
L. Poggio ◽  
C. A. Naranjo ◽  
R. A. Palacios ◽  
A. B. Andrada
Keyword(s):  
Chromosome Number ◽  
Interspecific Hybrids ◽  
Vegetative Reproduction ◽  
General Lack ◽  
Cytological Data ◽  
Natural Hybrids ◽  
Regular Meiosis ◽  
Putative Hybrids

Cytological results on 12 species and 4 putative hybrids of Prosopis are presented. Of these, 5 species and 4 hybrids have been hitherto unknown cytologically. The following species proved to be diploid (2n = 28) and constitute new chromosome number determinations for the genus: P. algarobilla Griseb., P. hassleri Harms, P. nigra (Griseb.) Hieron., P. patagonica Speg., P. tamarugo Phil. The diploid nature of some races of P. juliflora (Sw.) DC. is established; apparently under this taxon there are also tetraploid populations. The following putative interspecific hybrids showed regular meiosis with formation of 14 bivalents: P. vinalillo Stuck. (P. ruscifolia × P. alba?), P. alba × P. nigra? and P. hassleri × P. ruscifolia?.So far 28 taxa of the genus have been studied cytologically; 27 of these are diploid. The scarcity of polyploidy in the genus (3.5%) might be a consequence of the almost general lack of means of vegetative reproduction and of the absence of chromosome repatterning in primary speciation. Results of other authors concerning cytological data are also discussed.

A natural intergeneric hybrid of Gesneriaceae from Brazil

Phytotaxa ◽  
2021 ◽  
Vol 497 (2) ◽  
pp. 79-96
Author(s):  
ANDRÉA ONOFRE DE ARAUJO ◽  
MAURO PEIXOTO ◽  
CINTIA NEVES DE SOUZA ◽  
EDUARDO CUSTÓDIO GASPARINO ◽  
JULIANA TOLEDO FARIA ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Intergeneric Hybrid ◽  
Morphological Characters ◽  
Natural Hybrid ◽  
Pollen Data ◽  
Cytological Data ◽  
High Viability ◽  
Structural Abnormalities

A natural hybrid between Goyazia and Mandirola (Gloxiniinae, Gesneriaceae) from Cerrado (Brazil) is here described, supported by pollen morphology, cytological data and morphological characters. The microsporogenesis of Mandirola hirsuta and that of the hybrid were analyzed in order to evaluate the cytogenetic characteristics. The haploid chromosome numbers observed were n = 12 for M. hirsuta and n = 11, 13, 16 and 26 for the hybrid. Structural abnormalities (monads, dyads, triads and micronuclei) were observed at the final of the hybrid’s meiosis. High viability rates of the pollen were recorded for Goyazia and Mandirola (>90%) and low viability for the hybrid (34.7%). The pollen grains were acetolyzed, measured and photographed for pollen morphology analysis. Quantitative pollen data were analyzed through descriptive and multivariate statistics. The hybrid has intermediate pollen characteristics between G. petraea and M. hirsuta; it is more related to G. petraea by the measures of diameters and ectoapertures; it is more similar to M. hirsuta mainly regarding the microreticulum on the mesocolpium region. The hybrid and Mandirola share vegetative and flower size, while the colors of the hybrid are similar to Goyazia. Pollen morphology, cytological data and morphological characters brought clear evidence for the recognition of the intergeneric hybrid, which we named as Goydirola x punctata.

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