Chromosome Banding and Mechanism of Chromosome Aberrations

2021 ◽  
Author(s):  
Sanjay Kumar ◽  
Asikho Kiso ◽  
N. Abenthung Kithan

Chromosome identification depends on the morphological features of the chromosome and therefore karyotype and its banding pattern analyses are the most suitable technique to identify each and every chromosome of a chromosome complement. Moreover, aberrations caused by breaks play an important role in the evolution of a chromosome set and chromosome complement by decreasing or increasing the chromosome number. Therefore, both the aspects are discussed in detail in the present chapter. At present, the chapter will highlight the karyotype and its components, karyotype trends, evolution and its role in speciation, banding pattern and techniques, chromosome differentiation and linearization, banding applications and their uses, detection and analysis of chromosomal aberrations, chromosome and chromatid types of aberrations and mechanism of the formation of chromosome aberrations and breaks for karyotype evolutionary trends.

Phytotaxa ◽  
2016 ◽  
Vol 257 (3) ◽  
pp. 280 ◽  
Author(s):  
Hao Zhou ◽  
Si-rong Yi ◽  
Qi Gao ◽  
Jie Huang ◽  
Yu-jing Wei

Aspidistra revoluta (Asparagaceae) is described and illustrated as a new species from limestone areas in southern Chongqing Municipality, China. The new species can be distinguished from the other Aspidistra species by its unique umbrella-like pistil with large revolute stigma lobes that bent downwards and touch the base of the perigone. A detailed morphological comparison among A. revoluta, A. nanchuanensis and A. carnosa is provided. The pollen grains of A. revoluta are subspherical and inaperturate, with verrucous exine. The chromosome number is 2n = 38, and the karyotype is formulated as 2n = 22m + 6sm + 10st. The average length of chromosome complement is 4.50 μm, and the karyotype asymmetry indexes A1 and A2 are respectively 0.37±0.03 and 0.49±0.01.


Crustaceana ◽  
2011 ◽  
Vol 84 (12-13) ◽  
pp. 1497-1510 ◽  
Author(s):  
M. Pavlica ◽  
M. Mcžić ◽  
G. Klobučar ◽  
M. Šrut ◽  
I. Maguire ◽  
...  

AbstractThis study reports on the chromosome number and karyological characteristics of the endangered species of European crayfish, Astacus astacus and A. leptodactylus (Decapoda, Astacidae), both native to Croatian freshwater habitats. The karyotype of A. astacus and A. leptodactylus consists of 2n = 176 and 2n = 180 chromosomes, respectively. The haploid chromosome complement of A. astacus consists of 52 metacentric, 35 metacentric-submetacentric, and 1 acrocentric chromosomes. Fluorochrome staining with 4,6-diamino-2-phenylindole (DAPI) has revealed that the karyotypes of A. astacus and A. leptodactylus are characterized by large heterochromatic blocks located at centromeric and intercalary positions on the chromosomes. Interstitial heterochromatic blocks were more frequent in A. astacus than in A. leptodactylus. In both species pairing of chromosomes in meiosis was regular with the majority of bivalents in a ring- and a dumbbell-form. Fluorescence in situ hybridization (FISH) has revealed that two 45S rDNA loci were present in the investigated species. In A. astacus one of the two 45S rDNA-bearing chromosome pairs was highly heteromorphic, exhibiting a three-fold size difference between 45S rDNA sites on homologous chromosomes. Such a size difference was significantly less pronounced in A. leptodactylus. The karyotype differences between A. astacus and A. leptodactylus suggest changes in chromosome number as well as position of repetitive DNAs have played a role in the karyotype evolution of the species of Astacus.


Genetics ◽  
1981 ◽  
Vol 97 (2) ◽  
pp. 391-414
Author(s):  
Jan Dvořák ◽  
Patrick E McGuire

ABSTRACT Wheat cultivar Chinese Spring (Triticum aestivum L. em. Thell.) was crossed with cultivars Hope, Cheyenne and Timstein. In all three hybrids, the frequencies of pollen mother cells (PMCs) with univalents at metaphase I (MI) were higher than those in the parental cultivars. No multivalents were observed in the hybrids, indicating that the cultivars do not differ by translocations. Thirty-one Chinese Spring telosomic lines were then crossed with substitution lines in which single chromosomes of the three cultivars were substituted for their Chinese Spring homologues. The telosomic lines were also crossed with Chinese Spring. Data were collected on the frequencies (% of PMCs) of pairing of the telesomes with their homologues at MI and the regularity of pairing of the remaining 20 pairs of Chinese Spring chromosomes in the monotelodisomics obtained from these crosses. The reduced MI pairing in the intercultivar hybrids was caused primarily by chromosome differentiation, rather than by specific genes. Because the differentiation involved a large part of the chromosome complement in each hybrid, it was concluded that it could not be caused by structural changes such as inversions or translocations. In each case, the differentiation appeared to be unevenly distributed among the three wheat genomes. It is proposed that the same kind of differentiation, although of greater magnitude, differentiates homoeologous chromosomes and is responsible, together with structural differentiation, for poor chromosome pairing in interspecific hybrids.


Hereditas ◽  
2009 ◽  
Vol 76 (2) ◽  
pp. 305-314 ◽  
Author(s):  
LIISA HALKKA ◽  
O. HALKKA ◽  
U. SKARÉN ◽  
VERONICA SÖDERLUND

1976 ◽  
Vol 54 (10) ◽  
pp. 1135-1139 ◽  
Author(s):  
W. Michael Dennis

Cytological studies were made on the following taxa: C. addisonii, C. filifera, C. glaucophylla, C. pitcheri, C. reticulata, C. texensis, C. versicolor, and C. viorna. All species were found to have a somatic chromosome number of 16 with a uniform karyotype consisting of five pairs of metacentric chromosomes with centromeres in the median region and three pairs of acrocentric chromosomes, two pairs with centromeres in the terminal region and one pair with centromeres in the subterminal region. These findings agree with reports of chromosome number and karyotype for other species of Clematis and suggest a marked stability of chromosome complement in the genus.


Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 589-593 ◽  
Author(s):  
C. Pedersen ◽  
P. Langridge

Using the Aegilops tauschii clone pAs1 together with the barley clone pHvG38 for two-colour fluorescence in situ hybridization (FISH) the entire chromosome complement of hexaploid wheat was identified. The combination of the two probes allowed easy discrimination of the three genomes of wheat. The banding pattern obtained with the pHvG38 probe containing the GAA-satellite sequence was identical to the N-banding pattern of wheat. A detailed idiogram was constructed, including 73 GAA bands and 48 pAs1 bands. Identification of the wheat chromosomes by FISH will be particularly useful in connection with the physical mapping of other DNA sequences to chromosomes, or for chromosome identification in general, as an alternative to C-banding.Key words: Triticum aestivum, chromosome identification, fluorescence in situ hybridization, repetitive DNA sequences.


1970 ◽  
Vol 40 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Syeda Sharmeen Sultana ◽  
Hosne Ara ◽  
Sheikh Shamimul Alam

Alocasia fallax Schott and A. odora (Roxb.) Koch (Araceae) were investigated cytogenetically to confirm their taxonomic status. There is no report of 2n chromosome number for A. fallax in the available literature and internet information. Therefore the 2n chromosome number (2n = 28) found in this study is probably the first report for A. fallax. Alocasia odora showed exactly double 2n chromosome number (2n = 56) from A. fallax. In addition to chromosome number, the other karyotypic features of A. odora were exactly double for that of A. fallax. The centromeric formulae of A. fallax was 24 m + 4 sm whereas it is just double in A. odora. Total length of 2n chromosome complement of A. odora (62.58 μm) was almost double to A. fallax. The range of chromosomal length of the two species was almost same. Moreover, A. odora plant is much taller than A. fallax. All of these data suggests that A. odora might be an autotetraploid of A. fallax which in course of evolution had undergone some changes in GC-rich repeats. Key words: Alocasia; CMA; Karyotype analysis DOI: http://dx.doi.org/10.3329/bjb.v40i1.7998 Bangladesh J. Bot. 40(1): 53-56, 2011 (June)


2020 ◽  
Vol 6 (6) ◽  
pp. FSO580
Author(s):  
Muhammad Sanusi Yahaya ◽  
Mohd Shahrom Salisi ◽  
Nur Mahiza Md Isa ◽  
Goh Yong Meng ◽  
Abdwahid Haron

Background: A number of factors are known to reduce fertility rate in animals and one of the important categories of such factors is chromosome anomalies. They can occur with or without causing phenotypic abnormalities on animals; in some cases, they may directly affect meiosis, gametogenesis and the viability of conceptus. In many instances, balanced structural rearrangements can be transmitted to offspring, affecting fertility in subsequent generations. Aim: This work investigated the occurrence of chromosome aberrations in Rusa timorensis, Rusa unicolor and Axis axis raised in a nucleus deer farm in Malaysia with a history of declining fertility of unknown origin. Materials & methods: Blood samples were collected from 60 animals through venipuncture, cultured for 72 h and arrested at metaphase. SmartType® and Ideokar® software were used to karyotype the chromosomes. Results: We found 15 out of the 60 animals screened from both sexes harbor some form of chromosome aberration. Chromosomal aberrations exist at the rate of 25% and may not be unconnected with the observed reduced fertility on the farm. Further investigations should be carried out, especially on the offspring of the studied animals to transmission of these aberrations. The animals that are confirmed to transmit the chromosomal aberrations should be culled to arrest the propagation of their abnormalities.


1988 ◽  
Vol 43 (11-12) ◽  
pp. 948-954 ◽  
Author(s):  
Friedrich J. Otto

Abstract A preparation, staining and measuring protocol for high resolution flow cytometry of chromosomes was developed. This method allows us to identify all chromosome types and is suited for characterization of permanent cell lines and cell clones by establishing their flow karyotypes. In cell clones this procedure can be used for the detection of chromosomal aberrations which appear spontaneously or are induced by mutagen treatment and persist in the cell population.


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