CYTOGENETIC STUDIES IN THE GENUS PERSEA (LAURACEAE). I. KARYOLOGY OF SEVEN SPECIES

1975 ◽  
Vol 17 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Armando Garcia V.

Chromosome number determinations were made on 137 collections of seven Persea species. Persea americana Mill., P. schiedeana Nees, and P. aff. cinerascens Rands, had a diploid number of 24 as reported earlier. The first chromosome counts for four species are reported. Persea hintonii Allen (2n = 48) is the first tetraploid species found in this genus. Persea indica (L.) Spreng. (2n = 24) is the first Old World species to have its chromosome number reported. Persea donnell-smithii Mez and P. pachypoda Nees also have the diploid number (2n = 24). One triploid (2n = 36) and one tetraploid (2n = 48) individual were found in P. americana. Based on stomatal size, their maternal plants were considered to be triploid and diploid, respectively.This is the first karyotype study in Persea and also in the family Lauraceae. The karyotype in Persea is asymmetric. The chromosomes range in size from 2.3 µm to 6.1 µm. Persea americana has one pair of satellited chromosomes, which is the largest pair, two metacentric pairs and nine submetacentric pairs. Two of the submetacentric pairs are highly heterochromatic and both are attached to the nucleolus. All the other species have karyotypes very similar to P. americana.


2018 ◽  
Vol 12 (2) ◽  
pp. 163-170
Author(s):  
Tiago Marafiga Degrandi ◽  
Jean Carlo Pedroso de Oliveira ◽  
Amanda de Araújo Soares ◽  
Mario Angel Ledesma ◽  
Iris Hass ◽  
...  

Kingfishers comprise about 115 species of the family Alcedinidae, and are an interesting group for cytogenetic studies, for they are among birds with most heterogeneous karyotypes. However, cytogenetics knowledge in Kingfishers is extremely limited. Thus, the aim of this study was to describe the karyotype structure of the Ringed Kingfisher (Megaceryletorquata Linnaeus, 1766) and Green Kingfisher (Chloroceryleamericana Gmelin, 1788) and also compare them with related species in order to identify chromosomal rearrangements. The Ringed Kingfisher presented 2n = 84 and the Green Kingfisher had 2n = 94. The increase of the chromosome number in the Green Kingfisher possibly originated by centric fissions in macrochromosomes. In addition, karyotype comparisons in Alcedinidae show a heterogeneity in the size and morphology of macrochromosomes, and chromosome numbers ranging from 2n = 76 to 132. Thus, it is possible chromosomal fissions in macrochromosomes resulted in the increase of the diploid number, whereas chromosome fusions have originated the karyotypes with low diploid number.



2021 ◽  
Vol 78 ◽  
pp. 1-13
Author(s):  
Pim H Van Caspel ◽  
Axel Dalberg Poulsen ◽  
Michael Möller

Chromosome counts were obtained from six species of Costaceae from Asia. Our count of 2n = 18 for Cheilocostus speciosus confirms previous counts, and the other five counts have been made for the first time (Cheilocostus borneensis, Cheilocostus globosus, Cheilocostus sopuensis, Costus muluensis and Paracostus sp.). These chromosome counts reveal two somatic numbers, 2n = 18 and 2n = 36, of which the former is a new diploid number for the genus Paracostus. A comprehensive review of existing counts was conducted through literature and database searches. Mapping of these on a published comprehensive phylogenetic tree suggests that the diploid count of 2n = 18 is probably ancestral in the Costaceae, with repeated parallel evolution of tetraploidy and one case of octoploidy. The existence of triploid counts in several lineages harbouring polyploids suggests that diploids and tetraploids may exist in close proximity, and that crosses or meioticirregularities may lead to triploid genotypes occurring frequently.



2019 ◽  
Vol 13 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Bruno Cansanção Silva ◽  
Lucas Henrique Bonfim Souza ◽  
Juliana Chamorro-Rengifo ◽  
Douglas Araujo

Phaneropterinae is the largest subfamily of Tettigoniidae, distributed across the globe. There are few cytogenetic studies regarding this group, as in the case of the genus group Aniarae, which represents only two karyotyped species. The current study aims to analyze cytogenetically three species of Hyperophora Brunner von Wattenwyl, 1878 from Brazil. The male diploid number of Hyperophoraminor Brunner von Wattenwyl, 1891 and Hyperophoramajor Brunner von Wattenwyl, 1878 is 2n♂= 31, whereas Hyperophorabrasiliensis Brunner von Wattenwyl, 1878 has shown 2n♂= 29. These three species possess an X0 sex chromosome system and telo/acrocentric chromosome morphology. The only species found in the Pantanal biome, H.brasiliensis, can be chromosomally distinguished from the Cerrado biome species H.major and H.minor, due to the difference in chromosome number (2n♂= 29 and 2n♂= 31, respectively).



1988 ◽  
Vol 9 (3) ◽  
pp. 301-310 ◽  
Author(s):  
E. Solleder ◽  
M. Schmid

The karotypes of nine species of the family Agamidae were analyzed with various banding techniques and conventional cytogenetic stainings. Whereas the examined species of the genera Calotes and Leiolepis exhibit conservative karyotypes, the chromosome number and chromosome morphology varies considerably within the genus Agama. This is attributed to centric fusions between telocentric chromosomes and pericentric inversions within the chromosomes. None of the species demonstrated multiple quinacrine banding patterns in the euchromatic segments of the metaphase chromosomes. This is probably due to the special DNA organization in these organisms.



Author(s):  
Walia Gurinder Kaur ◽  
Chahal Sarabjit Singh ◽  
Singh Navdeep

Male germ cell chromosomes of Burmagomphus divaricatus, Burmagomphus pyramidalis and Burmagomphus sivalikensis of family Gomphidae have been investigated by using conventional staining, C-banding, silver nitrate staining and sequence specific staining. The species were collected from Punjab and Himachal Pradesh, India. All the species possess the chromosome number 2n = 23 which is the type number of the family. Terminal C bands and NOR’s are present at the autosomal bivalents and X chromosome is C positive and NOR rich in all the three species, while m bivalents show variation in distribution of C- heterochromatin and NOR’s. In the sequence specific staining, whole complement shows bright DAPI signals in B. divaricatus, bright CMA3 signals in B. pyramidalis and both DAPI and CMA3 signals in B. sivalikensis.



1973 ◽  
Vol 51 (2) ◽  
pp. 179-186 ◽  
Author(s):  
H.-C. Lim ◽  
V. R. Vickery ◽  
D. K. McE. Kevan

Twelve species of Gryllinae were studied to determine the number, morphology and behavior of their chromosomes. The male diploid numbers ranged from 19 to 31. Gryllus campestris and a population of "G. bimaculatus" from Singapore showed anomalies in chromosome behavior and structure, including breaks, stickiness, C-mitosis, polyploidy, lagging, unequal segregation and non-disjunction in the former and many aberrations and loss of fertility in the latter. One or two B-chromosomes occurred in some individuals of G. veletis, the chromosome number of this species thus varying from 2n ♀ = 29 to 31. In the Gryllinae, karyotypic differences are shown to be more useful than chromosome number at the species level; differences in chromosome number are useful taxonomically at the generic level, when combined with differences in karyotypes.



Zootaxa ◽  
2009 ◽  
Vol 2315 (1) ◽  
pp. 39-46 ◽  
Author(s):  
MARIA G. POGGIO ◽  
MARIA J. BRESSA ◽  
ALBA G. PAPESCHI ◽  
OSVALDO DI IORIO ◽  
PAOLA TURIENZO

The Cimicidae (Hemiptera) are known to be blood ectoparasites primarily on birds and bats. Three species of the subfamily Haematosiphoninae are known from Argentina: Acanthocrios furnarii, Ornithocoris toledoi, and Psitticimex uritui; all feed on diverse avian hosts. The chromosome number and male meiosis of A. furnarii, and P. uritui from new Argentinean samples are analyzed and compared with previous data. The sample of A. furnarii described by Ueshima (1966) with 2n = 32 + XY (male), strikingly differs from the present results (2n = 10 + XY, male). The diploid number of P. uritui agree with the previously reported by Ueshima (1966), 2n = 28 + X 1 X 2 Y (male). Taxonomical implications about the identity of A. furnarii are discussed and the mechanisms of the karyotype evolution of species belonging to Haematosiphoninae are proposed.



1959 ◽  
Vol 37 (5) ◽  
pp. 1063-1070 ◽  
Author(s):  
William F. Grant

Spontaneous triploid hybrids (2n = 49) were discovered between Amaranthus spinosus L. (2n = 34), a diploid species, and A. dubius Mart. ex Thellung (2n = 64) which was found to be a tetraploid. Meiosis in the hybrids was irregular and 15 univalents were most frequently found along with the bivalents pairing apparently allosyndetically (15 I's + 17 II's = 2n = 49) at metaphase I. Univalents were excluded from the telophase nuclei in both meiotic divisions resulting in supernumerary microspores and in a reduction in the mean size of the microspores. Consequently, the triploids were largely sterile and the few undersized seeds produced failed to germinate. Seed weight, seed volume, stomatal size, and pollen grain size were proportional to chromosome number in the parents only, not in their hybrids. Since A. dubius exhibits typical bivalent behavior in synapsis, it is considered to be an allotetraploid in which A. spinosus has been one progenitor. It is suggested that the diploid A. quitensis H. B. K. (2n = 32) might be the other progenitor, but from chromosome number relationships and morphological considerations more than two species may be involved. As a result of the high sterility of the triploids, gene exchange between the parental species must be of a very limited nature.



Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 882-889 ◽  
Author(s):  
Catherine M. Shanahan

Male scorpions from Australian species of the family Buthidae exhibit a unique combination of cytogenetic features including achiasmate meiosis, holocentric chromosomes, and extensive interchange heterozygosity. Chromosome number is highly conserved, with all species having a basic diploid number of 2n = 14. There is evidence that inbreeding has contributed to the establishment of populations with interchange heterozygotes, some exhibiting rings of up to 12 chromosomes. Although most populations contain both structural homozygotes and interchange heterozygotes, one population may exhibit fixed heterozygosity. It is argued that the interchange heterozygosity observed in buthids is of adaptive significance.Key words: interchange, chromosome polymorphism, achiasmate meiosis, holocentric chromosomes.



2019 ◽  
Vol 159 (1) ◽  
pp. 32-38
Author(s):  
Igor C.A. Seligmann ◽  
Ivanete O. Furo ◽  
Michelly S. dos Santos ◽  
Marcella M. Tagliarini ◽  
Cristiane C.D. Araujo ◽  
...  

Despite the variation observed in the diploid chromosome number of storks (Ciconiiformes, Ciconiidae), from 2n = 52 to 2n = 78, most reports have relied solely on analyses by conventional staining. As most species have similar macrochromosomes, some authors propose that karyotype evolution involves mainly fusions between microchromosomes, which are highly variable in species with different diploid numbers. In order to verify this hypothesis, in this study, the karyotypes of 2 species of storks from South America with different diploid numbers, the jabiru (Jabiru mycteria, 2n = 56) and the maguary stork (Ciconia maguary, 2n = 72), were analyzed by chromosome painting using whole chromosome probes from the macrochromosomes of Gallus gallus (GGA) and Leucopternis albicollis (LAL). The results revealed that J. mycteria and C. maguary share synteny within chromosome pairs 1-9 and Z. The syntenies to the macrochromosomes of G. gallus are conserved, except for GGA4, which is homologous to 2 different pairs, as in most species of birds. A fusion of GGA8 and GGA9 was observed in both species. Additionally, chromosomes corresponding to GGA4p and GGA6 are fused to other segments that did not hybridize to any of the macrochromosome probes used, suggesting that these segments correspond to microchromosomes. Hence, our data corroborate the proposed hypothesis that karyotype evolution is based on fusions involving microchromosomes. In view of the morphological constancy of the macrochromosome pairs in most Ciconiidae, we propose a putative ancestral karyotype for the family, including the GGA8/GGA9 fusion, and a diploid number of 2n = 78. The use of probes for microchromosome pairs should be the next step in identifying other synapomorphies that may help to clarify the phylogeny of this family.



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