THE STRANDEDNESS OF CHROMOSOMES: EVIDENCE FROM CHROMOSOMAL ABERRATIONS

1969 ◽  
Vol 11 (4) ◽  
pp. 783-793 ◽  
Author(s):  
John A. Heddle
Keyword(s):  
Chromosomal Aberrations ◽  
Chromosome Aberrations ◽  
Mitotic Cycle ◽  
Early Prophase ◽  
Chromosomal Replication ◽  
Chromatid Aberrations

If cells are irradiated late in the mitotic cycle (late G2 or early prophase), at the following anaphase they frequently exhibit characteristic chromosomal configurations known as sidearm bridges. These are often interpreted as sub-chromatid aberrations and are taken as evidence that chromosomes are multi-stranded. This interpretation, although recently challenged, is supported by experiments based upon the normal replication that converts chromatids to full chromosomes. The rationale is that aberrations involving only one chromatid of a chromosome are converted by replication to chromosome aberrations involving both chromatids. After replication, therefore, there should be no chromatid aberrations remaining unless the initial aberration involved less than a full chromatid. The results show that chromatid aberrations do appear after chromosomal replication: at the second mitosis after irradiation. Another experiment shows that most such chromatid aberrations are not the result of errors in the replication of previous chromatid aberrations.

scholarly journals Prevalence of chromosome anomalies in a deer farm with fertility decline in Malaysia

2020 ◽  
Vol 6 (6) ◽  
pp. FSO580
Author(s):  
Muhammad Sanusi Yahaya ◽  
Mohd Shahrom Salisi ◽  
Nur Mahiza Md Isa ◽  
Goh Yong Meng ◽  
Abdwahid Haron
Keyword(s):  
Chromosomal Aberrations ◽  
Chromosome Aberrations ◽  
Fertility Decline ◽  
Unknown Origin ◽  
Structural Rearrangements ◽  
Blood Samples ◽  
Chromosome Anomalies ◽  
Number Of Factors ◽  
Axis Axis ◽  
History Of

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.

Assessment of Persisting Chromosome Aberrations by Flow Karyotyping of Cloned Chinese Hamster Cells

1988 ◽  
Vol 43 (11-12) ◽  
pp. 948-954 ◽  
Author(s):  
Friedrich J. Otto
Keyword(s):  
Flow Cytometry ◽  
High Resolution ◽  
Cell Lines ◽  
Chromosomal Aberrations ◽  
Chromosome Aberrations ◽  
Chinese Hamster ◽  
Chinese Hamster Cells ◽  
Cell Clones ◽  
Permanent Cell

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.

Chromosome Banding and Mechanism of Chromosome Aberrations

2021 ◽  
Author(s):  
Sanjay Kumar ◽  
Asikho Kiso ◽  
N. Abenthung Kithan
Keyword(s):  
Chromosome Number ◽  
Chromosomal Aberrations ◽  
Banding Pattern ◽  
Chromosome Aberrations ◽  
Chromosome Banding ◽  
Chromosome Complement ◽  
Morphological Features ◽  
Evolutionary Trends ◽  
Chromosome Differentiation ◽  
Suitable Technique

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.

scholarly journals THE PRODUCTION OF CHROMOSOME ABERRATIONS IN VARIOUS MAMMALIAN CELLS BY TRIETHYLENEMELAMINE

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 317-326
Author(s):  
H E Luippold ◽  
P C Gooch ◽  
J G Brewen
Keyword(s):  
Dna Replication ◽  
Chromosome Aberrations ◽  
Mammalian Cells ◽  
Bone Marrow Cells ◽  
Predominant Type ◽  
Mammalian Tissues ◽  
Peripheral Leukocytes ◽  
Chromatid Aberrations ◽  
Pha Stimulation ◽  
Higher Doses

ABSTRACT The cytogenetic effects of triethylenemelamine (TEM) were studied using five different mammalian tissues. Treatments of 0.1 and 0.2 mg/kg TEM on differentiating mouse spermatogonia and bone marrow cells showed no significant differences in the frequency of chromosomal aberrations produced in these two tissues. At higher doses, however, the sensitivities of the two tissues appear to be different. The frequency of aberrations varies with time after treatment, with the greatest amount occurring at the later fixation times. Results of an experiment on primary spermatocytes indicated a correlation between the frequency of chromosome aberrations and DNA replication. Human peripheral leukocytes were utilized in an attempt to clarify the cellstage specificity of TEM-induced chromosome aberrations. Cultures were treated with TEM prior to PHA stimulation (G0), as well as various time intervals after stimulation (late G,1 S, and G2). The most sensitive stages of the cell cycle to aberration induction were later G1 and S, with chromatid aberrations the predominant type. A very low yield of chromosome damage was observed with the G0 and G1 treated stages. The experiments described tend to support the view that TEM is most effective at inducing aberrations when an intervening round of DNA replication has occurred.

scholarly journals ANALYSIS OF THE CHROMOSOME ABERRATIONS INDUCED BY X-RAYS IN SOMATIC CELLS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 77 (4) ◽  
pp. 701-719
Author(s):  
M Gatti ◽  
C Tanzarella ◽  
G Olivieri
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosome Aberrations ◽  
High Frequency ◽  
Low Frequency ◽  
X Rays ◽  
Somatic Pairing ◽  
Chromatid Aberrations ◽  
Radio Sensitivity ◽  
Two Peaks ◽  
Chromatid Exchanges

ABSTRACT A technique has been perfected for enabling good microscope preparations to be obtained from the larval ganglia of Drosophila melanogaster. This system was then tested with X-rays and an extensive series of data was obtained on the chromosome aberrations induced in the various stages of the cell cycle.—The analysis of the results obtained offers the following points of interest: (1) There exists a difference in radio-sensitivity between the two sexes. The females constantly display a greater frequency of both chromosome and chromatid aberrations. They also display a greater frequency of spontaneous aberrations. (2) In both sexes the overall chromosome damage is greater in cells irradiated in stages G2 and G1. These two peaks of greater radiosensitivity are produced by a high frequency of terminal deletions and chromatid exchanges and by a high frequency of dicentrics, respectively. (3) The aberrations are not distributed at random among the various chromosomes. On the average, the Y chromosome is found to be more resistant and the breaks are preferentially localized in the pericentromeric heterochromatin of the X chromosome and of the autosomes. (4) Somatic pairing influences the frequency and type of the chromosome aberrations induced. In this system, such an arrangement of the chromosomes results in a high frequency of exchanges and dicentrics between homologous chromosomes and a low frequency of scorable translocations. Moreover, somatic pairing, probably by preventing the formation of looped regions in the interphase chromosomes, results in the almost total absence of intrachanges at both chromosome and chromatid level.

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